step 8: harden docs and prepare rebuilt beta

AGENTS.md

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+# AGENTS.md
+
+## Current status
+
+Step 8 complete.
+
+## Completed steps
+
+Step 1 - Public API contract and pure core.
+Step 2 - Thread-safe state, commands, overlays, and cache model.
+Step 3 - Widget shell, sizing system, and GUI-thread frame pump.
+Step 4 - Tile manager, persistent cache, and asynchronous loading.
+Step 5 - Interaction: pan, zoom, and view commands.
+Step 6 - Overlay rendering and runtime update stress tests.
+Step 7 - Layers, provider switching, and clearing APIs.
+Step 8 - Documentation, hardening, and internal release.
+
+## Current step
+
+Internal rebuilt beta prepared.
+
+## Design decisions
+
+- Package is managed with uv.
+- Public import is `import dpg_map as dpgm`.
+- Dear PyGui calls are GUI-thread-only.
+- Runtime public calls enqueue commands or update logical state.
+- Overlay updates must not reset center/zoom.
+- The widget uses child_window + measured-size drawlist.
+- Tiles use a memory cache and persistent disk cache.
+- Tile providers are interchangeable.
+
+## Known issues
+
+None yet.
+
+## Commands used
+
+- Read `STEPS.md`, `FEATURES.md`, and `ARCHITECTURE.md`.
+- Created initial package, examples, tests, and agent-log structure.
+- Implemented public exports, exceptions, common types, tile provider registry, projection helpers, cache dataclasses, and GUI-dependent API stubs.
+- Added Step 1 tests for imports, providers, projection, and cache dataclasses.
+- Implemented global configuration, logical MapState, map registry, and current map context stack.
+- Implemented DirtyFlags, MapCommand, CommandKind, and coalescing MapCommandQueue.
+- Implemented logical marker, polyline, trajectory, and layer state models.
+- Implemented public runtime overlay/view/layer/provider/cache/debug wrappers against logical state without Dear PyGui calls.
+- Implemented memory cache metadata, disk cache path generation, metadata read/write, disk size scanning, and prune planning.
+- Added Step 2 tests for command coalescing, overlay/view isolation, copied trajectory inputs, coordinate length validation, layer state, disk path generation, and prune ordering.
+- Implemented `map_widget(...)` as a Dear PyGui child-window plus drawlist shell.
+- Implemented GUI-thread renderer frame pump that schedules frame callbacks, drains command queues, measures size, resizes the drawlist, and draws a placeholder background/attribution.
+- Implemented sizing helpers for measured size, last non-zero size preservation, visibility transitions, effective draw size, and resize dirty flags.
+- Implemented map interaction hit-rectangle calculation.
+- Implemented TileID, TileStatus, Tile, visible tile calculation, and TileManager.
+- Implemented asynchronous tile worker queue for disk reads, HTTP fetches, and image decoding.
+- Implemented provider-namespaced persistent cache writes, access metadata updates, clearing, and LRU pruning.
+- Implemented memory tile cache with visible-tile protection and deferred GUI-thread texture deletion.
+- Integrated tile result processing, stale generation/provider rejection, texture creation, and tile drawing into the GUI-thread renderer.
+- Added OpenStreetMap User-Agent warning/fallback and configured examples with example user agents.
+- Added Step 3 examples for basic map, window sizing, child-window sizing, table sizing, and hidden-tab sizing.
+- Added Step 4 cache stress example.
+- Added Step 3 tests for sizing transitions, zero-size preservation, resize dirty flags, command drain ordering, and hit rectangles.
+- Added Step 4 tests for visible tile calculation, stale result rejection, protected memory eviction, and tile image decoding.
+- Ran a Dear PyGui context smoke check for `map_widget` child-window/drawlist creation.
+- Ran `uv run pytest`.
+- Ran `uv run ruff check .`.
+- Ran `uv run ruff format .`.
+- Ran `uv run ruff format --check .`.
+- Ran `uv run pyright`.
+- Ran `uv run pytest`.
+- Ran `uv run ruff check .`.
+- Ran `uv run ruff format .`.
+- Ran `uv run ruff format --check .`.
+- Ran `uv run pyright`.
+- Ran a Dear PyGui context smoke check for `map_widget` child-window/drawlist/texture-registry creation.
+- Implemented left mouse drag panning using the measured drawlist rectangle.
+- Implemented mouse wheel zoom around the cursor.
+- Implemented projection-backed `screen_to_latlon`, `latlon_to_screen`, and zoom-fitting `fit_bounds`.
+- Attached Dear PyGui mouse handlers through the map handler registry.
+- Added interaction debug state for active drag and last mouse position.
+- Added Step 5 tests for pan, cursor zoom, view conversion, bounds fitting, and overlay/view isolation.
+- Added Pyright virtualenv settings so `uv run pyright` resolves installed dependencies.
+- Ran `uv run pytest`.
+- Ran `uv run ruff check .`.
+- Ran `uv run ruff format --check .`.
+- Ran `uv run pyright`.
+- Ran a Dear PyGui context smoke check for `map_widget` child-window/drawlist/texture-registry/handler-registry creation.
+- Implemented Dear PyGui draw-layer bookkeeping for background, tiles, overlays, and attribution.
+- Rendered markers, polylines, and trajectories from GUI-thread overlay snapshots.
+- Isolated overlay redraws so they clear only the overlay draw layer and do not clear tile draw commands or textures.
+- Added live background-thread marker and trajectory stress examples.
+- Added Step 6 tests for overlay draw-layer isolation, overlay-only dirty flags, threaded update coalescing, and view/drag-state isolation.
+- Updated `README.md` with Step 6 overlay rendering behavior and examples.
+- Ran `uv run ruff format .`.
+- Ran `uv run pytest`.
+- Ran `uv run pyright`.
+- Ran `uv run ruff check .`.
+- Ran `uv run ruff format --check .`.
+- Ran a Dear PyGui context smoke check for `map_widget` with marker, polyline, and trajectory overlays.
+- Added `z_index` support for `add_layer`, layer visibility/clearing tests, and cache-safe map-wide memory clearing.
+- Implemented provider switching that validates providers, clamps zoom to the new provider range, preserves overlays/center, increments generation, and queues GUI-thread tile invalidation.
+- Implemented provider-scoped disk cache clearing and cache-size scanning.
+- Exported `CacheStats` publicly.
+- Added `examples/custom_provider.py` and cache control/stat buttons to `examples/cache_stress.py`.
+- Updated `README.md` with Step 7 behavior and examples.
+- Added Step 7 tests for provider switch tile invalidation, provider-scoped disk clearing, queued disk clear commands, layer z-order updates, and public exports.
+- Ran `uv run ruff format .`.
+- Ran `uv run pytest`.
+- Ran `uv run ruff check .`.
+- Ran `uv run ruff format --check .`.
+- Ran `uv run pyright`.
+- Ran `uv run python -c "import dpg_map as dpgm; print(dpgm.list_providers())"`.
+- Added docstrings for public API functions.
+- Rewrote `README.md` with uv install, local editable dependency, basic usage, sizing, live update, custom provider, cache, OpenStreetMap, and thread-safety documentation.
+- Added Step 8 hardening tests for unknown maps, overlays, providers, invalid coordinates, mismatched coordinate lengths, empty trajectory support, deleted overlays, provider switching while tiles are loading, overlay updates during dragging, and public docstrings.
+- Bumped package version to `0.3.0b1` and updated the fallback OpenStreetMap User-Agent version.
+- Ran `uv run pytest`.
+- Ran `uv run ruff format .`.
+- Ran `uv run ruff check .`.
+- Ran `uv run ruff format --check .`.
+- Ran `uv run pyright`.
+- Tested editable install from `/tmp/dpg-map-editable-test` with `uv add --editable /home/hector/projects/dpg-map`.
+- Ran editable install import check: `uv run python -c "import dpg_map as dpgm; print(dpgm.list_providers())"`.
+- Ran `uv run python -m py_compile` across all example files.
+- Started `examples/basic_map.py` under a 5-second timeout; it launched without terminal errors and was stopped by timeout because the GUI loop blocks.
+- Ran `uv sync`.
+
+## Next action
+
+Commit and tag `v0.3.0b1`.

README.md

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+# dpg-map
+
+`dpg-map` is a Dear PyGui map widget for XYZ raster tiles and geographic overlays.
+
+The rebuilt beta exposes a stable public import:
+
+```python
+import dpg_map as dpgm
+```
+
+## Install
+
+Use `uv` for development and dependency management:
+
+```bash
+uv sync
+uv run pytest
+```
+
+From another local project, add this package as an editable dependency:
+
+```bash
+uv add --editable ../dpg-map
+uv run python -c "import dpg_map as dpgm; print(dpgm.list_providers())"
+```
+
+## Basic Map
+
+```python
+from typing import Any
+
+import dearpygui.dearpygui as _dpg
+import dpg_map as dpgm
+
+dpg: Any = _dpg
+
+dpgm.configure(user_agent="my-app/0.1 contact@example.com")
+
+dpg.create_context()
+dpg.create_viewport(title="Map", width=1000, height=700)
+
+with dpg.window(label="Map", width=-1, height=-1):
+    with dpgm.map_widget(tag="map", center=(47.9029, 1.9093), zoom=15, width=-1, height=-1):
+        dpgm.add_marker("vehicle", lat=47.9029, lon=1.9093, label="Vehicle")
+
+dpg.setup_dearpygui()
+dpg.show_viewport()
+dpg.start_dearpygui()
+dpg.destroy_context()
+```
+
+## Sizing
+
+The widget is a Dear PyGui `child_window` containing a measured drawlist. The child keeps the requested Dear PyGui sizing intent while the drawlist uses concrete measured pixels.
+
+Supported sizing modes:
+
+- `width=0` and `height=0` keep Dear PyGui default sizing.
+- `width=-1` and `height=-1` fill available space where Dear PyGui supports it.
+- Positive dimensions request fixed sizes.
+- `autosize_x` and `autosize_y` are passed to the child window.
+- Hidden layouts preserve the last non-zero measured size until visible again.
+
+Examples:
+
+```bash
+uv run python examples/sizing_window.py
+uv run python examples/sizing_child.py
+uv run python examples/sizing_table.py
+uv run python examples/hidden_tab.py
+```
+
+## Live Updates
+
+Runtime overlay updates are safe to call from background threads. They update logical state and enqueue renderer commands; Dear PyGui drawing, texture, handler, and viewport calls stay on the GUI thread.
+
+Live marker update:
+
+```python
+dpgm.add_marker("vehicle", lat=47.9029, lon=1.9093, map_tag="map")
+dpgm.update_marker("vehicle", lat=current_lat, lon=current_lon, map_tag="map")
+```
+
+Live trajectory update:
+
+```python
+dpgm.add_trajectory("track", points=[], map_tag="map")
+dpgm.update_trajectory("track", points=tuple(points), map_tag="map")
+```
+
+Stress examples:
+
+```bash
+uv run python examples/markers_live_thread.py
+uv run python examples/trajectory_live_thread.py
+```
+
+## Providers
+
+OpenStreetMap is registered as `osm` by default. Custom XYZ providers can be registered and selected at runtime:
+
+```python
+provider = dpgm.TileProvider(
+    name="custom",
+    url_template="https://example.com/{z}/{x}/{y}.png",
+    attribution="Tiles (c) Example",
+)
+dpgm.register_provider(provider)
+dpgm.set_provider("custom", map_tag="map")
+```
+
+Provider switching preserves overlays and center, clamps zoom to the new provider range, increments the tile generation, and ignores stale tile results from the previous provider.
+
+Example:
+
+```bash
+uv run python examples/custom_provider.py
+```
+
+## Cache
+
+Tiles use an in-memory cache and a persistent provider-namespaced disk cache.
+
+```python
+dpgm.configure(
+    user_agent="my-app/0.1 contact@example.com",
+    cache_dir=".tile-cache",
+    memory_cache_max_tiles=512,
+    disk_cache_max_bytes=2_000_000_000,
+)
+
+stats = dpgm.get_cache_stats(map_tag="map")
+dpgm.clear_memory_cache(map_tag="map")
+dpgm.clear_disk_cache(provider="osm")
+```
+
+`disk_cache_max_bytes=None` disables the disk size limit. Memory cache clears are routed through the renderer command queue so texture deletion happens on the GUI thread. Disk cache clears can target all providers or a single provider namespace.
+
+Cache example:
+
+```bash
+uv run python examples/cache_stress.py
+```
+
+## OpenStreetMap Usage
+
+The default OpenStreetMap provider requires attribution and should use an application-specific `User-Agent`.
+
+```python
+dpgm.configure(user_agent="my-product/1.0 contact@example.com")
+```
+
+If no user agent is configured, `dpg-map` emits a runtime warning and falls back to a package user agent. Applications are responsible for displaying provider attribution in accordance with provider terms; the renderer draws the provider attribution text on the map.
+
+## Thread-Safety Contract
+
+Public runtime functions are intended to be callable from non-GUI threads unless explicitly documented otherwise. They acquire map locks briefly, update logical state, and/or enqueue commands.
+
+Thread-safe runtime areas include:
+
+- view updates: `set_center`, `set_zoom`, `set_view`, `fit_bounds`
+- overlay updates: `add_marker`, `update_marker`, `update_trajectory`, `delete_overlay`
+- layer updates: `add_layer`, `show_layer`, `hide_layer`, `clear_layer`
+- provider/cache updates: `set_provider`, `clear_memory_cache`, `clear_disk_cache`
+
+`map_widget(...)` creates Dear PyGui items and must be used on the GUI thread inside an active Dear PyGui context.
+
+## Examples
+
+```bash
+uv run python examples/basic_map.py
+uv run python examples/cache_stress.py
+uv run python examples/custom_provider.py
+uv run python examples/markers_live_thread.py
+uv run python examples/trajectory_live_thread.py
+```

examples/.gitkeep

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+

examples/basic_map.py

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+from typing import Any
+
+import dearpygui.dearpygui as _dpg
+
+import dpg_map as dpgm
+
+dpg: Any = _dpg
+
+
+def main() -> None:
+    dpgm.configure(user_agent="dpg-map basic example")
+
+    dpg.create_context()
+    dpg.create_viewport(title="dpg-map basic", width=900, height=600)
+
+    with (
+        dpg.window(label="Map", width=-1, height=-1),
+        dpgm.map_widget(tag="map", center=(47.9029, 1.9093), zoom=15, width=-1, height=-1),
+    ):
+        dpgm.add_marker("vehicle", lat=47.9029, lon=1.9093)
+
+    dpg.setup_dearpygui()
+    dpg.show_viewport()
+    dpg.start_dearpygui()
+    dpg.destroy_context()
+
+
+if __name__ == "__main__":
+    main()

examples/cache_stress.py

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+from pathlib import Path
+from typing import Any
+
+import dearpygui.dearpygui as _dpg
+
+import dpg_map as dpgm
+
+dpg: Any = _dpg
+
+
+def main() -> None:
+    cache_dir = Path(__file__).resolve().parent / ".tile-cache"
+    dpgm.configure(
+        cache_dir=cache_dir,
+        memory_cache_max_tiles=32,
+        disk_cache_max_bytes=30_000_000,
+        prefetch_margin_tiles=1,
+        user_agent="dpg-map cache_stress example",
+    )
+
+    dpg.create_context()
+    dpg.create_viewport(title="dpg-map cache stress", width=1000, height=700)
+
+    def clear_memory() -> None:
+        dpgm.clear_memory_cache(map_tag="cache-map")
+
+    def clear_disk() -> None:
+        dpgm.clear_disk_cache(map_tag="cache-map")
+
+    def refresh_stats() -> None:
+        stats = dpgm.get_cache_stats(map_tag="cache-map")
+        dpg.set_value(
+            "cache-stats",
+            (
+                f"memory {stats.memory_tiles}/{stats.memory_max_tiles} tiles | "
+                f"disk {stats.disk_bytes // 1024} KiB | "
+                f"hits m:{stats.memory_hits} d:{stats.disk_hits}"
+            ),
+        )
+
+    with (
+        dpg.window(label="Cache Stress", width=-1, height=-1),
+    ):
+        with dpg.group(horizontal=True):
+            dpg.add_button(label="Clear Memory", callback=clear_memory)
+            dpg.add_button(label="Clear Disk", callback=clear_disk)
+            dpg.add_button(label="Stats", callback=refresh_stats)
+            dpg.add_text("", tag="cache-stats")
+        with dpgm.map_widget(
+            tag="cache-map",
+            center=(47.9029, 1.9093),
+            zoom=14,
+            width=-1,
+            height=-1,
+        ):
+            dpgm.add_marker("start", lat=47.9029, lon=1.9093, label="Orleans")
+
+    dpg.setup_dearpygui()
+    dpg.show_viewport()
+    dpg.start_dearpygui()
+    dpg.destroy_context()
+
+
+if __name__ == "__main__":
+    main()

examples/custom_provider.py

@@ -0,0 +1,52 @@
+from typing import Any
+
+import dearpygui.dearpygui as _dpg
+
+import dpg_map as dpgm
+
+dpg: Any = _dpg
+
+
+def main() -> None:
+    dpgm.configure(user_agent="dpg-map custom_provider example")
+    provider = dpgm.TileProvider(
+        name="carto-light",
+        url_template="https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}{r}.png",
+        subdomains=("a", "b", "c", "d"),
+        attribution="(c) OpenStreetMap contributors (c) CARTO",
+        file_extension="png",
+    )
+    if "carto-light" not in dpgm.list_providers():
+        dpgm.register_provider(provider)
+
+    dpg.create_context()
+    dpg.create_viewport(title="dpg-map custom provider", width=900, height=600)
+
+    def use_osm() -> None:
+        dpgm.set_provider("osm", map_tag="custom-provider-map")
+
+    def use_carto() -> None:
+        dpgm.set_provider("carto-light", map_tag="custom-provider-map")
+
+    with dpg.window(label="Custom Provider", width=-1, height=-1):
+        with dpg.group(horizontal=True):
+            dpg.add_button(label="OSM", callback=use_osm)
+            dpg.add_button(label="Carto", callback=use_carto)
+        with dpgm.map_widget(
+            tag="custom-provider-map",
+            provider="carto-light",
+            center=(47.9029, 1.9093),
+            zoom=13,
+            width=-1,
+            height=-1,
+        ):
+            dpgm.add_marker("orleans", lat=47.9029, lon=1.9093, label="Orleans")
+
+    dpg.setup_dearpygui()
+    dpg.show_viewport()
+    dpg.start_dearpygui()
+    dpg.destroy_context()
+
+
+if __name__ == "__main__":
+    main()

examples/hidden_tab.py

@@ -0,0 +1,27 @@
+from typing import Any
+
+import dearpygui.dearpygui as _dpg
+
+import dpg_map as dpgm
+
+dpg: Any = _dpg
+
+
+def main() -> None:
+    dpg.create_context()
+    dpg.create_viewport(title="dpg-map hidden tab", width=900, height=600)
+
+    with dpg.window(label="Hidden Tab Sizing", width=-1, height=-1), dpg.tab_bar():
+        with dpg.tab(label="First"):
+            dpg.add_text("Switch to the map tab.")
+        with dpg.tab(label="Map"), dpgm.map_widget(tag="map-hidden-tab", width=-1, height=500):
+            dpgm.add_marker("tab-marker", lat=35.0, lon=139.0)
+
+    dpg.setup_dearpygui()
+    dpg.show_viewport()
+    dpg.start_dearpygui()
+    dpg.destroy_context()
+
+
+if __name__ == "__main__":
+    main()

examples/markers_live_thread.py

@@ -0,0 +1,66 @@
+from __future__ import annotations
+
+from math import cos, sin
+from threading import Event, Thread
+from time import sleep
+from typing import Any
+
+import dearpygui.dearpygui as _dpg
+
+import dpg_map as dpgm
+
+dpg: Any = _dpg
+
+
+def main() -> None:
+    dpgm.configure(user_agent="dpg-map markers_live_thread example")
+    stop = Event()
+
+    dpg.create_context()
+    dpg.create_viewport(title="dpg-map live markers", width=1000, height=700)
+
+    with (
+        dpg.window(label="Live Markers", width=-1, height=-1),
+        dpgm.map_widget(
+            tag="live-markers-map", center=(47.9029, 1.9093), zoom=15, width=-1, height=-1
+        ),
+    ):
+        for index in range(12):
+            dpgm.add_marker(
+                f"vehicle-{index}",
+                lat=47.9029,
+                lon=1.9093,
+                label=str(index + 1),
+                show_label=True,
+                color=(240, 92, 70, 255),
+            )
+
+    def update_markers() -> None:
+        tick = 0
+        while not stop.is_set():
+            for index in range(12):
+                angle = tick * 0.08 + index * 0.52
+                radius = 0.0015 + (index % 4) * 0.0002
+                dpgm.update_marker(
+                    f"vehicle-{index}",
+                    lat=47.9029 + sin(angle) * radius,
+                    lon=1.9093 + cos(angle) * radius,
+                    map_tag="live-markers-map",
+                )
+            tick += 1
+            sleep(1 / 30)
+
+    worker = Thread(target=update_markers, name="dpg-map-live-markers", daemon=True)
+    worker.start()
+    try:
+        dpg.setup_dearpygui()
+        dpg.show_viewport()
+        dpg.start_dearpygui()
+    finally:
+        stop.set()
+        worker.join(timeout=1.0)
+        dpg.destroy_context()
+
+
+if __name__ == "__main__":
+    main()

examples/sizing_child.py

@@ -0,0 +1,28 @@
+from typing import Any
+
+import dearpygui.dearpygui as _dpg
+
+import dpg_map as dpgm
+
+dpg: Any = _dpg
+
+
+def main() -> None:
+    dpg.create_context()
+    dpg.create_viewport(title="dpg-map child sizing", width=900, height=600)
+
+    with (
+        dpg.window(label="Nested Child", width=-1, height=-1),
+        dpg.child_window(width=-1, height=420),
+        dpgm.map_widget(tag="map-child", width=-1, height=-1),
+    ):
+        dpgm.add_marker("inside-child", lat=47.0, lon=2.0)
+
+    dpg.setup_dearpygui()
+    dpg.show_viewport()
+    dpg.start_dearpygui()
+    dpg.destroy_context()
+
+
+if __name__ == "__main__":
+    main()

examples/sizing_table.py

@@ -0,0 +1,33 @@
+from typing import Any
+
+import dearpygui.dearpygui as _dpg
+
+import dpg_map as dpgm
+
+dpg: Any = _dpg
+
+
+def main() -> None:
+    dpg.create_context()
+    dpg.create_viewport(title="dpg-map table sizing", width=1000, height=600)
+
+    with (
+        dpg.window(label="Table Layout", width=-1, height=-1),
+        dpg.table(header_row=True, resizable=True, policy=dpg.mvTable_SizingStretchProp),
+    ):
+        dpg.add_table_column(label="Map")
+        dpg.add_table_column(label="Controls")
+        with dpg.table_row():
+            with dpg.table_cell(), dpgm.map_widget(tag="map-table", width=-1, height=500):
+                dpgm.add_marker("table-marker", lat=51.5, lon=-0.1)
+            with dpg.table_cell():
+                dpg.add_text("Resize the window and table columns.")
+
+    dpg.setup_dearpygui()
+    dpg.show_viewport()
+    dpg.start_dearpygui()
+    dpg.destroy_context()
+
+
+if __name__ == "__main__":
+    main()

examples/sizing_window.py

@@ -0,0 +1,27 @@
+from typing import Any
+
+import dearpygui.dearpygui as _dpg
+
+import dpg_map as dpgm
+
+dpg: Any = _dpg
+
+
+def main() -> None:
+    dpg.create_context()
+    dpg.create_viewport(title="dpg-map window sizing", width=900, height=600)
+
+    with (
+        dpg.window(label="Fill Window", width=-1, height=-1),
+        dpgm.map_widget(tag="map-window", width=-1, height=-1),
+    ):
+        dpgm.add_marker("center", lat=0.0, lon=0.0)
+
+    dpg.setup_dearpygui()
+    dpg.show_viewport()
+    dpg.start_dearpygui()
+    dpg.destroy_context()
+
+
+if __name__ == "__main__":
+    main()

examples/trajectory_live_thread.py

@@ -0,0 +1,76 @@
+from __future__ import annotations
+
+from collections import deque
+from math import cos, sin
+from threading import Event, Thread
+from time import sleep
+from typing import Any
+
+import dearpygui.dearpygui as _dpg
+
+import dpg_map as dpgm
+
+dpg: Any = _dpg
+
+
+def main() -> None:
+    dpgm.configure(user_agent="dpg-map trajectory_live_thread example")
+    stop = Event()
+    points: deque[tuple[float, float]] = deque(maxlen=240)
+
+    dpg.create_context()
+    dpg.create_viewport(title="dpg-map live trajectory", width=1000, height=700)
+
+    with (
+        dpg.window(label="Live Trajectory", width=-1, height=-1),
+        dpgm.map_widget(
+            tag="live-trajectory-map",
+            center=(47.9029, 1.9093),
+            zoom=15,
+            width=-1,
+            height=-1,
+        ),
+    ):
+        dpgm.add_trajectory(
+            "track",
+            points=[],
+            color=(250, 190, 80, 255),
+            thickness=3.0,
+            show_points=True,
+            point_stride=12,
+        )
+        dpgm.add_marker(
+            "head",
+            lat=47.9029,
+            lon=1.9093,
+            color=(72, 205, 154, 255),
+            radius=6,
+        )
+
+    def update_trajectory() -> None:
+        tick = 0
+        while not stop.is_set():
+            angle = tick * 0.06
+            lat = 47.9029 + sin(angle) * 0.0016 + sin(angle * 2.7) * 0.00025
+            lon = 1.9093 + cos(angle) * 0.0016
+            points.append((lat, lon))
+            snapshot = tuple(points)
+            dpgm.update_trajectory("track", points=snapshot, map_tag="live-trajectory-map")
+            dpgm.update_marker("head", lat=lat, lon=lon, map_tag="live-trajectory-map")
+            tick += 1
+            sleep(1 / 20)
+
+    worker = Thread(target=update_trajectory, name="dpg-map-live-trajectory", daemon=True)
+    worker.start()
+    try:
+        dpg.setup_dearpygui()
+        dpg.show_viewport()
+        dpg.start_dearpygui()
+    finally:
+        stop.set()
+        worker.join(timeout=1.0)
+        dpg.destroy_context()
+
+
+if __name__ == "__main__":
+    main()

pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "dpg-map"
-version = "0.1.0"
+version = "0.3.0b1"
-description = "Add your description here"
+description = "Dear PyGui map widget for XYZ raster tiles and geographic overlays"
 readme = "README.md"
 authors = [
     { name = "Hector van der Aa", email = "hector@h3cx.dev" }
@@ -27,3 +27,15 @@ dev = [
     "pytest>=9.0.3",
     "ruff>=0.15.14",
 ]
+
+[tool.ruff]
+line-length = 100
+target-version = "py311"
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "UP", "B", "SIM"]
+
+[tool.pyright]
+typeCheckingMode = "basic"
+venvPath = "."
+venv = ".venv"

src/dpg_map/__init__.py

@@ -1,2 +1,89 @@
+"""Public API for dpg-map."""
+
+from .api import (
+    add_layer,
+    add_marker,
+    add_polyline,
+    add_trajectory,
+    clear_disk_cache,
+    clear_layer,
+    clear_map,
+    clear_memory_cache,
+    configure,
+    delete_overlay,
+    fit_bounds,
+    get_cache_stats,
+    get_center,
+    get_map_debug_state,
+    get_zoom,
+    hide_layer,
+    latlon_to_screen,
+    screen_to_latlon,
+    set_center,
+    set_marker_label,
+    set_marker_position,
+    set_overlay_show,
+    set_polyline_points,
+    set_provider,
+    set_view,
+    set_zoom,
+    show_layer,
+    update_marker,
+    update_polyline,
+    update_trajectory,
+)
+from .cache import CacheStats
+from .providers import (
+    TileProvider,
+    get_provider,
+    list_providers,
+    register_provider,
+    unregister_provider,
+)
+from .widget import map_widget
+
+__all__ = [
+    "CacheStats",
+    "TileProvider",
+    "add_layer",
+    "add_marker",
+    "add_polyline",
+    "add_trajectory",
+    "clear_disk_cache",
+    "clear_layer",
+    "clear_map",
+    "clear_memory_cache",
+    "configure",
+    "delete_overlay",
+    "fit_bounds",
+    "get_cache_stats",
+    "get_center",
+    "get_map_debug_state",
+    "get_provider",
+    "get_zoom",
+    "hide_layer",
+    "latlon_to_screen",
+    "list_providers",
+    "map_widget",
+    "register_provider",
+    "screen_to_latlon",
+    "set_center",
+    "set_marker_label",
+    "set_marker_position",
+    "set_overlay_show",
+    "set_polyline_points",
+    "set_provider",
+    "set_view",
+    "set_zoom",
+    "show_layer",
+    "unregister_provider",
+    "update_marker",
+    "update_polyline",
+    "update_trajectory",
+]
+
+
 def main() -> None:
-    print("Hello from dpg-map!")
+    """Console entry point placeholder."""
+
+    print("dpg-map")

src/dpg_map/api.py

@@ -0,0 +1,662 @@
+"""Public API wrappers for dpg-map."""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+from dataclasses import asdict
+from math import isfinite
+from pathlib import Path
+from typing import Any
+
+from .cache import CacheStats, clear_disk_cache_path, disk_cache_root, disk_cache_size_bytes
+from .commands import CommandKind, MapCommand
+from .exceptions import (
+    CoordinateError,
+    InvalidProviderError,
+    MapNotFoundError,
+    OverlayNotFoundError,
+)
+from .interaction import latlon_to_screen_in_state, screen_to_latlon_in_state
+from .overlays import LayerState, MarkerOverlay, Overlay, PolylineOverlay, TrajectoryOverlay
+from .projection import latlon_to_world
+from .providers import TileProvider, get_provider
+from .sizing import effective_draw_size
+from .state import (
+    DirtyFlags,
+    configure_state,
+    find_map_for_overlay,
+    get_config,
+    get_map_state,
+    list_map_states,
+    mark_dirty,
+)
+from .types import Bounds, LatLon, Point, Tag
+
+
+def _validate_latlon(lat: float, lon: float) -> LatLon:
+    lat_value = float(lat)
+    lon_value = float(lon)
+    if not isfinite(lat_value) or not isfinite(lon_value):
+        raise CoordinateError("coordinates must be finite numbers")
+    if lat_value < -90.0 or lat_value > 90.0:
+        raise CoordinateError("latitude must be between -90 and 90")
+    if lon_value < -180.0 or lon_value > 180.0:
+        raise CoordinateError("longitude must be between -180 and 180")
+    return (lat_value, lon_value)
+
+
+def _points_from_inputs(
+    points: Sequence[LatLon] | None = None,
+    *,
+    lats: Sequence[float] | None = None,
+    lons: Sequence[float] | None = None,
+) -> tuple[LatLon, ...]:
+    if points is not None and (lats is not None or lons is not None):
+        raise CoordinateError("provide either points or lats/lons, not both")
+    if points is not None:
+        return tuple(_validate_latlon(lat, lon) for lat, lon in points)
+    if lats is None and lons is None:
+        return ()
+    if lats is None or lons is None:
+        raise CoordinateError("lats and lons must be provided together")
+    lat_values = tuple(lats)
+    lon_values = tuple(lons)
+    if len(lat_values) != len(lon_values):
+        raise CoordinateError("lats and lons must have the same length")
+    return tuple(
+        _validate_latlon(lat, lon) for lat, lon in zip(lat_values, lon_values, strict=True)
+    )
+
+
+def _ensure_layer(state: Any, layer_name: str, z_index: int = 0, show: bool = True) -> LayerState:
+    layer = state.layers.get(layer_name)
+    if layer is None:
+        layer = LayerState(layer_name, z_index=z_index, show=show)
+        state.layers[layer_name] = layer
+    return layer
+
+
+def _overlay_payload(overlay: Overlay) -> dict[str, Any]:
+    return {"tag": overlay.tag, "overlay": asdict(overlay)}
+
+
+def _queue(state: Any, kind: CommandKind, payload: dict[str, Any]) -> None:
+    state.command_queue.put(MapCommand(kind=kind, map_tag=state.tag, payload=payload))
+
+
+def configure(
+    *,
+    user_agent: str | None = None,
+    cache_dir: str | Path | None = None,
+    default_provider: str | TileProvider = "osm",
+    memory_cache_max_tiles: int = 512,
+    disk_cache_max_bytes: int | None = 2_000_000_000,
+    prefetch_margin_tiles: int = 1,
+    tile_worker_count: int = 4,
+    overlay_update_policy: str = "coalesce",
+    debug: bool = False,
+) -> None:
+    """Configure package-wide defaults used by subsequently created maps."""
+
+    configure_state(
+        user_agent=user_agent,
+        cache_dir=cache_dir,
+        default_provider=default_provider,
+        memory_cache_max_tiles=memory_cache_max_tiles,
+        disk_cache_max_bytes=disk_cache_max_bytes,
+        prefetch_margin_tiles=prefetch_margin_tiles,
+        tile_worker_count=tile_worker_count,
+        overlay_update_policy=overlay_update_policy,
+        debug=debug,
+    )
+
+
+def set_center(lat: float, lon: float, *, map_tag: Tag | None = None) -> None:
+    """Set a map center without changing its zoom."""
+
+    set_view(center=_validate_latlon(lat, lon), map_tag=map_tag)
+
+
+def get_center(*, map_tag: Tag | None = None) -> LatLon:
+    """Return the current logical center of a map."""
+
+    state = get_map_state(map_tag)
+    with state.lock:
+        return state.center
+
+
+def set_zoom(zoom: int, *, map_tag: Tag | None = None) -> None:
+    """Set a map zoom, clamped to the map/provider zoom range."""
+
+    set_view(zoom=zoom, map_tag=map_tag)
+
+
+def get_zoom(*, map_tag: Tag | None = None) -> int:
+    """Return the current logical zoom of a map."""
+
+    state = get_map_state(map_tag)
+    with state.lock:
+        return state.zoom
+
+
+def set_view(
+    *,
+    center: LatLon | None = None,
+    zoom: int | None = None,
+    map_tag: Tag | None = None,
+) -> None:
+    """Set map center and/or zoom as one logical view update."""
+
+    state = get_map_state(map_tag)
+    with state.lock:
+        payload: dict[str, Any] = {}
+        if center is not None:
+            state.center = _validate_latlon(center[0], center[1])
+            payload["center"] = state.center
+        if zoom is not None:
+            state.zoom = max(state.min_zoom, min(state.max_zoom, int(zoom)))
+            payload["zoom"] = state.zoom
+        if not payload:
+            return
+        mark_dirty(state, DirtyFlags.VIEW | DirtyFlags.TILES | DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.SET_VIEW, payload)
+
+
+def fit_bounds(bounds: Bounds, *, map_tag: Tag | None = None) -> None:
+    """Set center and zoom so geographic bounds fit the current draw area."""
+
+    (south_west, north_east) = bounds
+    south, west = _validate_latlon(south_west[0], south_west[1])
+    north, east = _validate_latlon(north_east[0], north_east[1])
+    south, north = min(south, north), max(south, north)
+    state = get_map_state(map_tag)
+    with state.lock:
+        width, height = effective_draw_size(state)
+        padding = 32
+        usable_width = max(1, width - padding * 2)
+        usable_height = max(1, height - padding * 2)
+        tile_size = state.provider.tile_size
+        target_zoom = state.min_zoom
+        for candidate_zoom in range(state.max_zoom, state.min_zoom - 1, -1):
+            west_x, north_y = latlon_to_world(north, west, candidate_zoom, tile_size)
+            east_x, south_y = latlon_to_world(south, east, candidate_zoom, tile_size)
+            world_size = tile_size * (2**candidate_zoom)
+            x_span = abs(east_x - west_x)
+            x_span = min(x_span, world_size - x_span)
+            y_span = abs(south_y - north_y)
+            if x_span <= usable_width and y_span <= usable_height:
+                target_zoom = candidate_zoom
+                break
+    set_view(center=((south + north) / 2.0, (west + east) / 2.0), zoom=target_zoom, map_tag=map_tag)
+
+
+def screen_to_latlon(x: float, y: float, *, map_tag: Tag | None = None) -> LatLon:
+    """Convert map-local screen coordinates to latitude/longitude."""
+
+    state = get_map_state(map_tag)
+    return screen_to_latlon_in_state(state, float(x), float(y))
+
+
+def latlon_to_screen(lat: float, lon: float, *, map_tag: Tag | None = None) -> Point:
+    """Convert latitude/longitude to map-local screen coordinates."""
+
+    lat_value, lon_value = _validate_latlon(lat, lon)
+    state = get_map_state(map_tag)
+    return latlon_to_screen_in_state(state, lat_value, lon_value)
+
+
+def add_marker(
+    tag: Tag,
+    *,
+    lat: float,
+    lon: float,
+    label: str | None = None,
+    layer: str = "default",
+    show: bool = True,
+    map_tag: Tag | None = None,
+    **kwargs: Any,
+) -> Tag:
+    """Add or replace a marker overlay and return its tag."""
+
+    state = get_map_state(map_tag)
+    color = kwargs.get("color", (255, 80, 80, 255))
+    radius = float(kwargs.get("radius", 5.0))
+    show_label = bool(kwargs.get("show_label", False))
+    user_data = kwargs.get("user_data")
+    callback = kwargs.get("callback")
+    with state.lock:
+        marker = MarkerOverlay(
+            tag=tag,
+            map_tag=state.tag,
+            layer=layer,
+            show=show,
+            user_data=user_data,
+            lat=_validate_latlon(lat, lon)[0],
+            lon=_validate_latlon(lat, lon)[1],
+            label=label,
+            color=color,
+            radius=radius,
+            show_label=show_label,
+            callback=callback,
+        )
+        state.overlays[tag] = marker
+        _ensure_layer(state, layer).overlay_tags.add(tag)
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.ADD_OVERLAY, _overlay_payload(marker))
+    return tag
+
+
+def add_polyline(
+    tag: Tag,
+    *,
+    points: Sequence[LatLon] | None = None,
+    lats: Sequence[float] | None = None,
+    lons: Sequence[float] | None = None,
+    layer: str = "default",
+    show: bool = True,
+    map_tag: Tag | None = None,
+    **kwargs: Any,
+) -> Tag:
+    """Add or replace a polyline overlay and return its tag."""
+
+    state = get_map_state(map_tag)
+    copied_points = _points_from_inputs(points, lats=lats, lons=lons)
+    with state.lock:
+        polyline = PolylineOverlay(
+            tag=tag,
+            map_tag=state.tag,
+            layer=layer,
+            show=show,
+            user_data=kwargs.get("user_data"),
+            points=copied_points,
+            color=kwargs.get("color", (80, 180, 255, 255)),
+            thickness=float(kwargs.get("thickness", 2.0)),
+            closed=bool(kwargs.get("closed", False)),
+            simplify=bool(kwargs.get("simplify", True)),
+        )
+        state.overlays[tag] = polyline
+        _ensure_layer(state, layer).overlay_tags.add(tag)
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.ADD_OVERLAY, _overlay_payload(polyline))
+    return tag
+
+
+def add_trajectory(
+    tag: Tag,
+    *,
+    points: Sequence[LatLon] | None = None,
+    lats: Sequence[float] | None = None,
+    lons: Sequence[float] | None = None,
+    layer: str = "default",
+    show: bool = True,
+    map_tag: Tag | None = None,
+    **kwargs: Any,
+) -> Tag:
+    """Add or replace a trajectory overlay and return its tag."""
+
+    state = get_map_state(map_tag)
+    copied_points = _points_from_inputs(points, lats=lats, lons=lons)
+    timestamps = kwargs.get("timestamps")
+    copied_timestamps = tuple(timestamps) if timestamps is not None else None
+    if copied_timestamps is not None and len(copied_timestamps) != len(copied_points):
+        raise CoordinateError("timestamps must have the same length as trajectory points")
+    point_stride = int(kwargs.get("point_stride", 1))
+    if point_stride < 1:
+        raise ValueError("point_stride must be >= 1")
+    with state.lock:
+        trajectory = TrajectoryOverlay(
+            tag=tag,
+            map_tag=state.tag,
+            layer=layer,
+            show=show,
+            user_data=kwargs.get("user_data"),
+            points=copied_points,
+            timestamps=copied_timestamps,
+            color=kwargs.get("color", (255, 180, 60, 255)),
+            thickness=float(kwargs.get("thickness", 2.0)),
+            show_points=bool(kwargs.get("show_points", False)),
+            point_stride=point_stride,
+        )
+        state.overlays[tag] = trajectory
+        _ensure_layer(state, layer).overlay_tags.add(tag)
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.ADD_OVERLAY, _overlay_payload(trajectory))
+    return tag
+
+
+def update_marker(
+    tag: Tag,
+    *,
+    lat: float | None = None,
+    lon: float | None = None,
+    label: str | None = None,
+    map_tag: Tag | None = None,
+    **kwargs: Any,
+) -> None:
+    """Update marker properties without changing the map view."""
+
+    state = find_map_for_overlay(tag, map_tag)
+    with state.lock:
+        overlay = state.overlays.get(tag)
+        if not isinstance(overlay, MarkerOverlay):
+            raise OverlayNotFoundError(f"marker not found: {tag}")
+        if lat is not None or lon is not None:
+            overlay.lat, overlay.lon = _validate_latlon(
+                overlay.lat if lat is None else lat,
+                overlay.lon if lon is None else lon,
+            )
+        if label is not None:
+            overlay.label = label
+        if "show" in kwargs:
+            overlay.show = bool(kwargs["show"])
+        if "color" in kwargs:
+            overlay.color = kwargs["color"]
+        if "radius" in kwargs:
+            overlay.radius = float(kwargs["radius"])
+        overlay.touch()
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.UPDATE_OVERLAY, _overlay_payload(overlay))
+
+
+def update_polyline(
+    tag: Tag,
+    *,
+    points: Sequence[LatLon] | None = None,
+    lats: Sequence[float] | None = None,
+    lons: Sequence[float] | None = None,
+    map_tag: Tag | None = None,
+    **kwargs: Any,
+) -> None:
+    """Update polyline properties without changing the map view."""
+
+    state = find_map_for_overlay(tag, map_tag)
+    with state.lock:
+        overlay = state.overlays.get(tag)
+        if not isinstance(overlay, PolylineOverlay):
+            raise OverlayNotFoundError(f"polyline not found: {tag}")
+        if points is not None or lats is not None or lons is not None:
+            overlay.points = _points_from_inputs(points, lats=lats, lons=lons)
+        if "show" in kwargs:
+            overlay.show = bool(kwargs["show"])
+        if "color" in kwargs:
+            overlay.color = kwargs["color"]
+        if "thickness" in kwargs:
+            overlay.thickness = float(kwargs["thickness"])
+        overlay.touch()
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.UPDATE_OVERLAY, _overlay_payload(overlay))
+
+
+def update_trajectory(
+    tag: Tag,
+    *,
+    points: Sequence[LatLon] | None = None,
+    lats: Sequence[float] | None = None,
+    lons: Sequence[float] | None = None,
+    map_tag: Tag | None = None,
+    **kwargs: Any,
+) -> None:
+    """Update trajectory properties without changing the map view."""
+
+    state = find_map_for_overlay(tag, map_tag)
+    with state.lock:
+        overlay = state.overlays.get(tag)
+        if not isinstance(overlay, TrajectoryOverlay):
+            raise OverlayNotFoundError(f"trajectory not found: {tag}")
+        if points is not None or lats is not None or lons is not None:
+            overlay.points = _points_from_inputs(points, lats=lats, lons=lons)
+        if "timestamps" in kwargs:
+            timestamps = kwargs["timestamps"]
+            overlay.timestamps = tuple(timestamps) if timestamps is not None else None
+            if overlay.timestamps is not None and len(overlay.timestamps) != len(overlay.points):
+                raise CoordinateError("timestamps must have the same length as trajectory points")
+        if "show" in kwargs:
+            overlay.show = bool(kwargs["show"])
+        if "color" in kwargs:
+            overlay.color = kwargs["color"]
+        if "thickness" in kwargs:
+            overlay.thickness = float(kwargs["thickness"])
+        overlay.touch()
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.UPDATE_OVERLAY, _overlay_payload(overlay))
+
+
+def set_marker_position(tag: Tag, lat: float, lon: float, *, map_tag: Tag | None = None) -> None:
+    """Set a marker latitude/longitude."""
+
+    update_marker(tag, lat=lat, lon=lon, map_tag=map_tag)
+
+
+def set_marker_label(tag: Tag, label: str, *, map_tag: Tag | None = None) -> None:
+    """Set a marker label."""
+
+    update_marker(tag, label=label, map_tag=map_tag)
+
+
+def set_polyline_points(
+    tag: Tag,
+    points: Sequence[LatLon],
+    *,
+    map_tag: Tag | None = None,
+) -> None:
+    """Replace a polyline point sequence."""
+
+    update_polyline(tag, points=points, map_tag=map_tag)
+
+
+def set_overlay_show(tag: Tag, show: bool, *, map_tag: Tag | None = None) -> None:
+    """Show or hide an overlay without deleting it."""
+
+    state = find_map_for_overlay(tag, map_tag)
+    with state.lock:
+        overlay = state.overlays.get(tag)
+        if overlay is None:
+            raise OverlayNotFoundError(f"overlay not found: {tag}")
+        overlay.show = bool(show)
+        overlay.touch()
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.UPDATE_OVERLAY, _overlay_payload(overlay))
+
+
+def delete_overlay(tag: Tag, *, map_tag: Tag | None = None) -> None:
+    """Delete an overlay from its map and layer."""
+
+    state = find_map_for_overlay(tag, map_tag)
+    with state.lock:
+        overlay = state.overlays.pop(tag, None)
+        if overlay is None:
+            raise OverlayNotFoundError(f"overlay not found: {tag}")
+        layer = state.layers.get(overlay.layer)
+        if layer is not None:
+            layer.overlay_tags.discard(tag)
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.DELETE_OVERLAY, {"tag": tag})
+
+
+def _cache_target_states(map_tag: Tag | None) -> list[Any]:
+    if map_tag is not None:
+        return [get_map_state(map_tag)]
+    try:
+        return [get_map_state(None)]
+    except MapNotFoundError:
+        return list_map_states()
+
+
+def add_layer(
+    name: str,
+    *,
+    z_index: int | None = None,
+    show: bool = True,
+    map_tag: Tag | None = None,
+) -> None:
+    """Create or update a logical overlay layer."""
+
+    state = get_map_state(map_tag)
+    with state.lock:
+        layer = _ensure_layer(
+            state,
+            name,
+            z_index=len(state.layers) if z_index is None else int(z_index),
+            show=show,
+        )
+        if z_index is not None:
+            layer.z_index = int(z_index)
+        layer.show = show
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(
+            state,
+            CommandKind.ADD_LAYER,
+            {"name": name, "show": show, "z_index": layer.z_index},
+        )
+
+
+def show_layer(name: str, *, map_tag: Tag | None = None) -> None:
+    """Show all overlays assigned to a layer."""
+
+    state = get_map_state(map_tag)
+    with state.lock:
+        _ensure_layer(state, name).show = True
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.SET_LAYER_VISIBILITY, {"name": name, "show": True})
+
+
+def hide_layer(name: str, *, map_tag: Tag | None = None) -> None:
+    """Hide all overlays assigned to a layer."""
+
+    state = get_map_state(map_tag)
+    with state.lock:
+        _ensure_layer(state, name).show = False
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.SET_LAYER_VISIBILITY, {"name": name, "show": False})
+
+
+def clear_layer(name: str, *, map_tag: Tag | None = None) -> None:
+    """Delete all overlays assigned to a layer."""
+
+    state = get_map_state(map_tag)
+    with state.lock:
+        layer = _ensure_layer(state, name)
+        for overlay_tag in tuple(layer.overlay_tags):
+            state.overlays.pop(overlay_tag, None)
+        layer.overlay_tags.clear()
+        mark_dirty(state, DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.CLEAR_LAYER, {"name": name})
+
+
+def clear_map(*, map_tag: Tag | None = None) -> None:
+    """Delete all overlays and invalidate map tile resources."""
+
+    state = get_map_state(map_tag)
+    with state.lock:
+        state.overlays.clear()
+        for layer in state.layers.values():
+            layer.overlay_tags.clear()
+        state.generation += 1
+        mark_dirty(state, DirtyFlags.OVERLAYS | DirtyFlags.TILES)
+        _queue(state, CommandKind.CLEAR_MAP, {})
+
+
+def set_provider(provider: str | TileProvider, *, map_tag: Tag | None = None) -> None:
+    """Switch a map to another tile provider while preserving overlays."""
+
+    if isinstance(provider, str):
+        provider_obj = get_provider(provider)
+    elif isinstance(provider, TileProvider):
+        provider_obj = provider
+    else:
+        raise InvalidProviderError("provider must be a provider name or TileProvider")
+    state = get_map_state(map_tag)
+    with state.lock:
+        if state.provider == provider_obj:
+            return
+        state.provider = provider_obj
+        state.min_zoom = provider_obj.min_zoom
+        state.max_zoom = provider_obj.max_zoom
+        state.zoom = max(state.min_zoom, min(state.max_zoom, state.zoom))
+        state.generation += 1
+        mark_dirty(state, DirtyFlags.PROVIDER | DirtyFlags.TILES | DirtyFlags.OVERLAYS)
+        _queue(state, CommandKind.SET_PROVIDER, {"provider": provider_obj.name})
+
+
+def clear_memory_cache(*, map_tag: Tag | None = None) -> None:
+    """Clear decoded in-memory tile data through the renderer command queue."""
+
+    for state in _cache_target_states(map_tag):
+        with state.lock:
+            state.generation += 1
+            mark_dirty(state, DirtyFlags.TILES)
+            _queue(state, CommandKind.CLEAR_MEMORY_CACHE, {})
+
+
+def clear_disk_cache(provider: str | None = None, *, map_tag: Tag | None = None) -> None:
+    """Clear persistent tile cache data globally or for one map/provider."""
+
+    if provider is not None:
+        get_provider(provider)
+    if map_tag is None:
+        clear_disk_cache_path(get_config().cache_dir, provider=provider)
+        return
+    state = get_map_state(map_tag)
+    with state.lock:
+        state.generation += 1
+        mark_dirty(state, DirtyFlags.TILES)
+        _queue(state, CommandKind.CLEAR_DISK_CACHE, {"provider": provider})
+
+
+def get_cache_stats(*, map_tag: Tag | None = None) -> CacheStats:
+    """Return memory and disk cache diagnostics."""
+
+    config = get_config()
+    if map_tag is None:
+        cache_dir = config.cache_dir
+        return CacheStats(
+            memory_max_tiles=config.memory_cache_max_tiles,
+            disk_bytes=disk_cache_size_bytes(cache_dir),
+            disk_max_bytes=config.disk_cache_max_bytes,
+            disk_path=disk_cache_root(cache_dir),
+        )
+    state = get_map_state(map_tag)
+    with state.lock:
+        tile_snapshot = state.tile_manager.snapshot()
+        return CacheStats(
+            memory_tiles=tile_snapshot.memory_tiles,
+            memory_max_tiles=config.memory_cache_max_tiles,
+            memory_hits=tile_snapshot.memory_hits,
+            memory_misses=tile_snapshot.memory_misses,
+            disk_bytes=disk_cache_size_bytes(state.cache_dir),
+            disk_max_bytes=config.disk_cache_max_bytes,
+            disk_hits=tile_snapshot.disk_hits,
+            disk_misses=tile_snapshot.disk_misses,
+            disk_path=disk_cache_root(state.cache_dir),
+        )
+
+
+def get_map_debug_state(*, map_tag: Tag | None = None) -> dict[str, Any]:
+    """Return a diagnostic snapshot for a map."""
+
+    state = get_map_state(map_tag)
+    with state.lock:
+        return {
+            "tag": state.tag,
+            "center": state.center,
+            "zoom": state.zoom,
+            "requested_size": (state.requested_width, state.requested_height),
+            "measured_size": (state.measured_width, state.measured_height),
+            "visible": state.is_visible,
+            "provider": state.provider.name,
+            "overlay_count": len(state.overlays),
+            "layers": {
+                name: {
+                    "show": layer.show,
+                    "z_index": layer.z_index,
+                    "overlay_count": len(layer.overlay_tags),
+                }
+                for name, layer in state.layers.items()
+            },
+            "dirty_flags": int(state.dirty),
+            "pending_command_count": len(state.command_queue),
+            "generation": state.generation,
+            "active_drag": state.interaction.active_drag,
+            "last_mouse_position": state.interaction.last_mouse_position,
+            "tiles": asdict(state.tile_manager.snapshot()),
+        }

src/dpg_map/cache.py

@@ -0,0 +1,301 @@
+"""Memory and disk cache helpers."""
+
+from __future__ import annotations
+
+import json
+import shutil
+from dataclasses import asdict, dataclass, field
+from pathlib import Path
+from time import time
+from typing import Any
+
+from platformdirs import user_cache_dir
+
+from .exceptions import CacheError
+
+
+@dataclass(frozen=True, slots=True)
+class CacheStats:
+    """Public cache statistics snapshot."""
+
+    memory_tiles: int = 0
+    memory_max_tiles: int = 0
+    memory_hits: int = 0
+    memory_misses: int = 0
+    disk_bytes: int = 0
+    disk_max_bytes: int | None = None
+    disk_hits: int = 0
+    disk_misses: int = 0
+    disk_path: Path | None = None
+
+
+@dataclass(slots=True)
+class MemoryCacheConfig:
+    """Initial memory cache configuration."""
+
+    max_tiles: int = 512
+
+
+@dataclass(slots=True)
+class DiskCacheConfig:
+    """Initial persistent disk cache configuration."""
+
+    path: Path | None = None
+    max_bytes: int | None = 2_000_000_000
+
+
+@dataclass(slots=True)
+class MemoryCacheEntry:
+    """Metadata for one in-memory tile."""
+
+    tile_id: object
+    size_bytes: int = 0
+    last_accessed_at: float = field(default_factory=time)
+    protected: bool = False
+    texture_tag: object | None = None
+
+
+@dataclass(slots=True)
+class MemoryCacheModel:
+    """Small LRU metadata model for decoded/runtime tiles."""
+
+    max_tiles: int = 512
+    entries: dict[object, MemoryCacheEntry] = field(default_factory=dict)
+    hits: int = 0
+    misses: int = 0
+
+    def record_access(self, tile_id: object) -> MemoryCacheEntry | None:
+        """Mark an entry as recently used and return it if present."""
+
+        entry = self.entries.get(tile_id)
+        if entry is None:
+            self.misses += 1
+            return None
+        self.hits += 1
+        entry.last_accessed_at = time()
+        return entry
+
+    def put(self, entry: MemoryCacheEntry) -> None:
+        """Insert or replace entry metadata."""
+
+        entry.last_accessed_at = time()
+        self.entries[entry.tile_id] = entry
+
+    def plan_evictions(self) -> list[object]:
+        """Return tile IDs that can be evicted without touching GUI resources."""
+
+        overflow = len(self.entries) - self.max_tiles
+        if overflow <= 0:
+            return []
+        candidates = [entry for entry in self.entries.values() if not entry.protected]
+        candidates.sort(key=lambda entry: entry.last_accessed_at)
+        return [entry.tile_id for entry in candidates[:overflow]]
+
+
+@dataclass(frozen=True, slots=True)
+class DiskCacheMetadata:
+    """Persistent metadata stored next to a tile file."""
+
+    url: str = ""
+    etag: str | None = None
+    last_modified: str | None = None
+    expires: str | None = None
+    downloaded_at: float = 0.0
+    last_accessed_at: float = 0.0
+    size_bytes: int = 0
+
+
+@dataclass(frozen=True, slots=True)
+class DiskCacheEntry:
+    """Scanned disk cache file plus metadata."""
+
+    tile_path: Path
+    metadata_path: Path
+    metadata: DiskCacheMetadata
+
+
+def default_cache_dir() -> Path:
+    """Return the default persistent cache directory."""
+
+    return Path(user_cache_dir("dpg-map", appauthor=False))
+
+
+def disk_cache_root(cache_dir: str | Path | None = None) -> Path:
+    """Resolve the disk cache root path."""
+
+    return Path(cache_dir).expanduser() if cache_dir is not None else default_cache_dir()
+
+
+def tile_cache_path(
+    cache_dir: str | Path | None,
+    provider_name: str,
+    z: int,
+    x: int,
+    y: int,
+    extension: str | None = None,
+) -> Path:
+    """Return the provider-namespaced persistent tile path."""
+
+    ext = (extension or "png").lstrip(".")
+    safe_provider = provider_name.replace("/", "_")
+    return disk_cache_root(cache_dir) / safe_provider / str(z) / str(x) / f"{y}.{ext}"
+
+
+def tile_metadata_path(tile_path: Path) -> Path:
+    """Return the metadata path for a tile path."""
+
+    return tile_path.with_suffix(".json")
+
+
+def read_disk_metadata(path: Path) -> DiskCacheMetadata:
+    """Read a metadata JSON file, returning defaults for missing metadata."""
+
+    if not path.exists():
+        return DiskCacheMetadata()
+    try:
+        raw: dict[str, Any] = json.loads(path.read_text(encoding="utf-8"))
+    except OSError as exc:
+        raise CacheError(f"could not read cache metadata: {path}") from exc
+    except json.JSONDecodeError as exc:
+        raise CacheError(f"invalid cache metadata JSON: {path}") from exc
+
+    return DiskCacheMetadata(
+        url=str(raw.get("url", "")),
+        etag=raw.get("etag"),
+        last_modified=raw.get("last_modified"),
+        expires=raw.get("expires"),
+        downloaded_at=float(raw.get("downloaded_at", 0.0)),
+        last_accessed_at=float(raw.get("last_accessed_at", 0.0)),
+        size_bytes=int(raw.get("size_bytes", 0)),
+    )
+
+
+def write_disk_metadata(path: Path, metadata: DiskCacheMetadata) -> None:
+    """Write metadata JSON next to a tile file."""
+
+    try:
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_text(json.dumps(asdict(metadata), sort_keys=True), encoding="utf-8")
+    except OSError as exc:
+        raise CacheError(f"could not write cache metadata: {path}") from exc
+
+
+def touch_disk_metadata(path: Path, *, accessed_at: float | None = None) -> None:
+    """Update only the last access timestamp for a metadata file."""
+
+    metadata = read_disk_metadata(path)
+    write_disk_metadata(
+        path,
+        DiskCacheMetadata(
+            url=metadata.url,
+            etag=metadata.etag,
+            last_modified=metadata.last_modified,
+            expires=metadata.expires,
+            downloaded_at=metadata.downloaded_at,
+            last_accessed_at=time() if accessed_at is None else accessed_at,
+            size_bytes=metadata.size_bytes,
+        ),
+    )
+
+
+def scan_disk_cache(cache_dir: str | Path | None) -> list[DiskCacheEntry]:
+    """Scan tile files under a disk cache root."""
+
+    root = disk_cache_root(cache_dir)
+    if not root.exists():
+        return []
+    entries: list[DiskCacheEntry] = []
+    for path in root.rglob("*"):
+        if not path.is_file() or path.suffix == ".json":
+            continue
+        metadata_path = tile_metadata_path(path)
+        metadata = read_disk_metadata(metadata_path)
+        size_bytes = metadata.size_bytes or path.stat().st_size
+        if size_bytes != metadata.size_bytes:
+            metadata = DiskCacheMetadata(
+                url=metadata.url,
+                etag=metadata.etag,
+                last_modified=metadata.last_modified,
+                expires=metadata.expires,
+                downloaded_at=metadata.downloaded_at,
+                last_accessed_at=metadata.last_accessed_at,
+                size_bytes=size_bytes,
+            )
+        entries.append(DiskCacheEntry(path, metadata_path, metadata))
+    return entries
+
+
+def disk_cache_size_bytes(
+    cache_dir: str | Path | None,
+    *,
+    provider: str | None = None,
+) -> int:
+    """Return total bytes for cached tile files, optionally scoped to one provider."""
+
+    if provider is None:
+        return sum(entry.metadata.size_bytes for entry in scan_disk_cache(cache_dir))
+    safe_provider = provider.replace("/", "_")
+    provider_root = disk_cache_root(cache_dir) / safe_provider
+    if not provider_root.exists():
+        return 0
+    return sum(entry.metadata.size_bytes for entry in scan_disk_cache(provider_root))
+
+
+def plan_disk_prune(
+    cache_dir: str | Path | None,
+    max_bytes: int | None,
+    *,
+    protected_paths: set[Path] | None = None,
+) -> list[Path]:
+    """Return tile paths that should be pruned by LRU order without deleting them."""
+
+    if max_bytes is None:
+        return []
+    protected = {path.resolve() for path in protected_paths or set()}
+    entries = scan_disk_cache(cache_dir)
+    total = sum(entry.metadata.size_bytes for entry in entries)
+    if total <= max_bytes:
+        return []
+
+    candidates = [entry for entry in entries if entry.tile_path.resolve() not in protected]
+    candidates.sort(key=lambda entry: entry.metadata.last_accessed_at)
+    prune: list[Path] = []
+    for entry in candidates:
+        if total <= max_bytes:
+            break
+        prune.append(entry.tile_path)
+        total -= entry.metadata.size_bytes
+    return prune
+
+
+def prune_disk_cache(
+    cache_dir: str | Path | None,
+    max_bytes: int | None,
+    *,
+    protected_paths: set[Path] | None = None,
+) -> list[Path]:
+    """Delete LRU tile files until the cache fits the configured limit."""
+
+    planned = plan_disk_prune(cache_dir, max_bytes, protected_paths=protected_paths)
+    for path in planned:
+        metadata_path = tile_metadata_path(path)
+        try:
+            path.unlink(missing_ok=True)
+            metadata_path.unlink(missing_ok=True)
+        except OSError as exc:
+            raise CacheError(f"could not prune cached tile: {path}") from exc
+    return planned
+
+
+def clear_disk_cache_path(cache_dir: str | Path | None, *, provider: str | None = None) -> None:
+    """Remove persistent tile cache files under a cache root."""
+
+    root = disk_cache_root(cache_dir)
+    if provider is not None:
+        root = root / provider.replace("/", "_")
+    if not root.exists():
+        return
+    try:
+        shutil.rmtree(root)
+    except OSError as exc:
+        raise CacheError(f"could not clear disk cache: {root}") from exc

src/dpg_map/commands.py

@@ -0,0 +1,113 @@
+"""Command models for GUI-thread rendering work."""
+
+from __future__ import annotations
+
+from collections import OrderedDict, deque
+from dataclasses import dataclass, field
+from enum import Enum
+from threading import RLock
+from time import monotonic
+from typing import Any
+
+from .types import Tag
+
+
+class CommandKind(Enum):
+    """Commands that the GUI thread can apply in order."""
+
+    SET_VIEW = "set_view"
+    SET_PROVIDER = "set_provider"
+    ADD_OVERLAY = "add_overlay"
+    UPDATE_OVERLAY = "update_overlay"
+    DELETE_OVERLAY = "delete_overlay"
+    SET_LAYER_VISIBILITY = "set_layer_visibility"
+    ADD_LAYER = "add_layer"
+    CLEAR_LAYER = "clear_layer"
+    CLEAR_MAP = "clear_map"
+    CLEAR_MEMORY_CACHE = "clear_memory_cache"
+    CLEAR_DISK_CACHE = "clear_disk_cache"
+
+
+@dataclass(frozen=True, slots=True)
+class MapCommand:
+    """A command submitted from public API calls to the GUI-thread renderer."""
+
+    kind: CommandKind
+    map_tag: Tag
+    payload: dict[str, Any] = field(default_factory=dict)
+    created_at: float = field(default_factory=monotonic)
+
+
+class MapCommandQueue:
+    """Thread-safe command queue with bounded coalescing for high-rate updates."""
+
+    _VIEW_KEY = "__view__"
+
+    def __init__(self) -> None:
+        self._lock = RLock()
+        self._ordered: deque[MapCommand] = deque()
+        self._overlay_updates: OrderedDict[tuple[Tag, Tag], MapCommand] = OrderedDict()
+        self._view_updates: OrderedDict[Tag, MapCommand] = OrderedDict()
+
+    def put(self, command: MapCommand) -> None:
+        """Queue a command, coalescing update commands where ordering permits."""
+
+        with self._lock:
+            if command.kind is CommandKind.UPDATE_OVERLAY:
+                overlay_tag = command.payload.get("tag")
+                if overlay_tag is None:
+                    self._ordered.append(command)
+                    return
+                key = (command.map_tag, overlay_tag)
+                self._ordered.append(command)
+                self._overlay_updates[key] = command
+                return
+
+            if command.kind is CommandKind.SET_VIEW:
+                self._ordered.append(command)
+                self._view_updates[command.map_tag] = command
+                return
+
+            self._ordered.append(command)
+
+    def drain(self) -> list[MapCommand]:
+        """Return pending commands in render order and clear the queue."""
+
+        with self._lock:
+            drained: list[MapCommand] = []
+            while self._ordered:
+                command = self._ordered.popleft()
+                if command.kind is CommandKind.UPDATE_OVERLAY:
+                    overlay_tag = command.payload.get("tag")
+                    if not isinstance(overlay_tag, str | int):
+                        drained.append(command)
+                        continue
+                    key = (command.map_tag, overlay_tag)
+                    latest = self._overlay_updates.get(key)
+                    if latest is command:
+                        drained.append(command)
+                        del self._overlay_updates[key]
+                    continue
+
+                if command.kind is CommandKind.SET_VIEW:
+                    latest = self._view_updates.get(command.map_tag)
+                    if latest is command:
+                        drained.append(command)
+                        del self._view_updates[command.map_tag]
+                    continue
+
+                drained.append(command)
+
+            return drained
+
+    def __len__(self) -> int:
+        with self._lock:
+            return len(self._ordered)
+
+    def clear(self) -> None:
+        """Drop all pending commands."""
+
+        with self._lock:
+            self._ordered.clear()
+            self._overlay_updates.clear()
+            self._view_updates.clear()

src/dpg_map/diagnostics.py

@@ -0,0 +1 @@
+"""Diagnostics and debug state helpers."""

src/dpg_map/draw_layers.py

@@ -0,0 +1,46 @@
+"""Draw layer bookkeeping helpers."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any
+
+from .types import Tag
+
+
+@dataclass(frozen=True, slots=True)
+class DrawLayerTags:
+    """Internal Dear PyGui draw layer tags for one map."""
+
+    background: str
+    tiles: str
+    overlays: str
+    attribution: str
+
+
+def draw_layer_tags(map_tag: Tag) -> DrawLayerTags:
+    """Return stable internal draw layer tags for a map."""
+
+    return DrawLayerTags(
+        background=f"{map_tag}##layer-background",
+        tiles=f"{map_tag}##layer-tiles",
+        overlays=f"{map_tag}##layer-overlays",
+        attribution=f"{map_tag}##layer-attribution",
+    )
+
+
+def ensure_draw_layers(dpg: Any, *, drawlist_tag: Tag, map_tag: Tag) -> DrawLayerTags:
+    """Create draw layers if needed and return their tags."""
+
+    tags = draw_layer_tags(map_tag)
+    for layer_tag in (tags.background, tags.tiles, tags.overlays, tags.attribution):
+        if not dpg.does_item_exist(layer_tag):
+            dpg.add_draw_layer(parent=drawlist_tag, tag=layer_tag)
+    return tags
+
+
+def clear_draw_layer(dpg: Any, layer_tag: Tag) -> None:
+    """Clear one draw layer without touching sibling layers."""
+
+    if dpg.does_item_exist(layer_tag):
+        dpg.delete_item(layer_tag, children_only=True)

src/dpg_map/exceptions.py

@@ -0,0 +1,49 @@
+"""Public exception types for dpg-map."""
+
+
+class DpgMapError(Exception):
+    """Base exception for all public dpg-map errors."""
+
+
+class DpgMapNotImplementedError(DpgMapError, NotImplementedError):
+    """Raised by public APIs that are intentionally stubbed during the rebuild."""
+
+
+class ProviderError(DpgMapError):
+    """Base exception for tile provider errors."""
+
+
+class ProviderExistsError(ProviderError):
+    """Raised when registering a provider name that already exists."""
+
+
+class ProviderNotFoundError(ProviderError):
+    """Raised when a requested tile provider is not registered."""
+
+
+class InvalidProviderError(ProviderError, ValueError):
+    """Raised when a tile provider definition is invalid."""
+
+
+class ProjectionError(DpgMapError, ValueError):
+    """Raised when geographic projection input is invalid."""
+
+
+class MapNotFoundError(DpgMapError, KeyError):
+    """Raised when a requested map tag is not registered."""
+
+
+class OverlayNotFoundError(DpgMapError, KeyError):
+    """Raised when a requested overlay tag is not registered."""
+
+
+class CoordinateError(DpgMapError, ValueError):
+    """Raised when geographic coordinate input is invalid."""
+
+
+class ThreadingError(DpgMapError):
+    """Raised when an operation violates dpg-map threading rules."""
+
+
+class CacheError(DpgMapError):
+    """Raised when cache metadata or paths cannot be handled."""

src/dpg_map/interaction.py

@@ -0,0 +1,233 @@
+"""Map interaction state and handlers."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from math import isfinite
+from typing import Any
+
+from .commands import CommandKind, MapCommand
+from .projection import latlon_to_world, screen_to_world, world_to_latlon
+from .sizing import effective_draw_size
+from .state import DirtyFlags, MapState, mark_dirty
+from .types import LatLon, Point
+
+
+@dataclass(frozen=True, slots=True)
+class HitRect:
+    """Screen-space rectangle used for map interaction tests."""
+
+    x: float
+    y: float
+    width: float
+    height: float
+
+    @property
+    def right(self) -> float:
+        return self.x + self.width
+
+    @property
+    def bottom(self) -> float:
+        return self.y + self.height
+
+    def contains(self, x: float, y: float) -> bool:
+        return self.x <= x <= self.right and self.y <= y <= self.bottom
+
+
+def calculate_hit_rect(state: MapState, drawlist_pos: tuple[float, float]) -> HitRect:
+    """Return the map interaction rectangle for a drawlist position."""
+
+    width, height = effective_draw_size(state)
+    return HitRect(float(drawlist_pos[0]), float(drawlist_pos[1]), float(width), float(height))
+
+
+def screen_to_latlon_in_state(state: MapState, x: float, y: float) -> LatLon:
+    """Convert map-local screen coordinates to latitude/longitude."""
+
+    with state.lock:
+        width, height = effective_draw_size(state)
+        center = state.center
+        zoom = state.zoom
+        tile_size = state.provider.tile_size
+    world_x, world_y = screen_to_world(
+        float(x),
+        float(y),
+        center=center,
+        zoom=zoom,
+        width=width,
+        height=height,
+        tile_size=tile_size,
+    )
+    return world_to_latlon(world_x, world_y, zoom, tile_size)
+
+
+def latlon_to_screen_in_state(state: MapState, lat: float, lon: float) -> Point:
+    """Convert latitude/longitude to map-local screen coordinates."""
+
+    with state.lock:
+        width, height = effective_draw_size(state)
+        center = state.center
+        zoom = state.zoom
+        tile_size = state.provider.tile_size
+    world_x, world_y = latlon_to_world(lat, lon, zoom, tile_size)
+    center_x, center_y = latlon_to_world(center[0], center[1], zoom, tile_size)
+    return (world_x - center_x + width / 2.0, world_y - center_y + height / 2.0)
+
+
+def pan_state_by_pixels(state: MapState, dx: float, dy: float) -> LatLon:
+    """Pan the map by a mouse drag delta in screen pixels."""
+
+    with state.lock:
+        if dx == 0 and dy == 0:
+            return state.center
+        center = state.center
+        zoom = state.zoom
+        tile_size = state.provider.tile_size
+        world_size = tile_size * (2**zoom)
+        center_x, center_y = latlon_to_world(center[0], center[1], zoom, tile_size)
+        new_x = (center_x - dx) % world_size
+        new_y = min(max(center_y - dy, 0.0), float(world_size))
+        state.center = world_to_latlon(new_x, new_y, zoom, tile_size)
+        mark_dirty(state, DirtyFlags.VIEW | DirtyFlags.TILES | DirtyFlags.OVERLAYS)
+        state.command_queue.put(
+            MapCommand(
+                kind=CommandKind.SET_VIEW,
+                map_tag=state.tag,
+                payload={"center": state.center},
+            )
+        )
+        return state.center
+
+
+def zoom_state_at_screen_point(
+    state: MapState,
+    *,
+    screen_x: float,
+    screen_y: float,
+    delta: float,
+) -> int:
+    """Zoom the map around a map-local screen point where possible."""
+
+    if delta == 0 or not isfinite(delta):
+        with state.lock:
+            return state.zoom
+
+    with state.lock:
+        old_zoom = state.zoom
+        new_zoom = max(state.min_zoom, min(state.max_zoom, old_zoom + (1 if delta > 0 else -1)))
+        if new_zoom == old_zoom:
+            return old_zoom
+
+        width, height = effective_draw_size(state)
+        tile_size = state.provider.tile_size
+        anchor_latlon = screen_to_latlon_in_state(state, screen_x, screen_y)
+        anchor_x, anchor_y = latlon_to_world(
+            anchor_latlon[0],
+            anchor_latlon[1],
+            new_zoom,
+            tile_size,
+        )
+        world_size = tile_size * (2**new_zoom)
+        center_x = (anchor_x - (screen_x - width / 2.0)) % world_size
+        center_y = min(max(anchor_y - (screen_y - height / 2.0), 0.0), float(world_size))
+
+        state.zoom = new_zoom
+        state.center = world_to_latlon(center_x, center_y, new_zoom, tile_size)
+        mark_dirty(state, DirtyFlags.VIEW | DirtyFlags.TILES | DirtyFlags.OVERLAYS)
+        state.command_queue.put(
+            MapCommand(
+                kind=CommandKind.SET_VIEW,
+                map_tag=state.tag,
+                payload={"center": state.center, "zoom": state.zoom},
+            )
+        )
+        return state.zoom
+
+
+def handle_mouse_down(state: MapState, mouse_pos: tuple[float, float], hit_rect: HitRect) -> None:
+    """Begin a drag if the left mouse button starts inside the map rectangle."""
+
+    with state.lock:
+        if not state.is_visible or not hit_rect.contains(mouse_pos[0], mouse_pos[1]):
+            state.interaction.active_drag = False
+            state.interaction.last_mouse_position = None
+            return
+        state.interaction.active_drag = True
+        state.interaction.last_mouse_position = mouse_pos
+
+
+def handle_mouse_drag(state: MapState, mouse_pos: tuple[float, float]) -> None:
+    """Update center from a mouse drag event."""
+
+    with state.lock:
+        if not state.interaction.active_drag:
+            return
+        last_pos = state.interaction.last_mouse_position
+        state.interaction.last_mouse_position = mouse_pos
+    if last_pos is None:
+        return
+    pan_state_by_pixels(state, mouse_pos[0] - last_pos[0], mouse_pos[1] - last_pos[1])
+
+
+def handle_mouse_release(state: MapState) -> None:
+    """End any active drag."""
+
+    with state.lock:
+        state.interaction.active_drag = False
+        state.interaction.last_mouse_position = None
+
+
+def handle_mouse_wheel(
+    state: MapState,
+    *,
+    mouse_pos: tuple[float, float],
+    wheel_delta: float,
+    hit_rect: HitRect,
+) -> None:
+    """Apply wheel zoom when the cursor is over the concrete map rectangle."""
+
+    if not hit_rect.contains(mouse_pos[0], mouse_pos[1]):
+        return
+    zoom_state_at_screen_point(
+        state,
+        screen_x=mouse_pos[0] - hit_rect.x,
+        screen_y=mouse_pos[1] - hit_rect.y,
+        delta=wheel_delta,
+    )
+
+
+def update_drag_from_button_state(
+    state: MapState,
+    *,
+    mouse_pos: tuple[float, float],
+    hit_rect: HitRect,
+    is_down: bool,
+) -> None:
+    """Poll left-button state and keep drag interaction moving."""
+
+    with state.lock:
+        active_drag = state.interaction.active_drag
+
+    if not is_down:
+        if active_drag:
+            handle_mouse_release(state)
+        return
+
+    if active_drag:
+        handle_mouse_drag(state, mouse_pos)
+        return
+
+    if hit_rect.contains(mouse_pos[0], mouse_pos[1]):
+        handle_mouse_down(state, mouse_pos, hit_rect)
+
+
+def wheel_delta_from_app_data(app_data: Any) -> float:
+    """Normalize Dear PyGui mouse wheel callback data."""
+
+    if isinstance(app_data, int | float):
+        return float(app_data)
+    if isinstance(app_data, (list, tuple)) and app_data:
+        value = app_data[-1]
+        if isinstance(value, int | float):
+            return float(value)
+    return 0.0

src/dpg_map/overlays.py

@@ -0,0 +1,72 @@
+"""Logical overlay models."""
+
+from __future__ import annotations
+
+from collections.abc import Callable
+from dataclasses import dataclass, field
+from typing import Any
+
+from .types import Color, LatLon, Tag
+
+
+@dataclass(slots=True)
+class Overlay:
+    """Base logical overlay state."""
+
+    tag: Tag
+    map_tag: Tag
+    layer: str
+    show: bool = True
+    user_data: Any = None
+    revision: int = 0
+
+    def touch(self) -> None:
+        """Mark this overlay as changed."""
+
+        self.revision += 1
+
+
+@dataclass(slots=True)
+class MarkerOverlay(Overlay):
+    """Logical marker overlay."""
+
+    lat: float = 0.0
+    lon: float = 0.0
+    label: str | None = None
+    color: Color = (255, 80, 80, 255)
+    radius: float = 5.0
+    show_label: bool = False
+    callback: Callable[..., Any] | None = None
+
+
+@dataclass(slots=True)
+class PolylineOverlay(Overlay):
+    """Logical polyline overlay."""
+
+    points: tuple[LatLon, ...] = ()
+    color: Color = (80, 180, 255, 255)
+    thickness: float = 2.0
+    closed: bool = False
+    simplify: bool = True
+
+
+@dataclass(slots=True)
+class TrajectoryOverlay(Overlay):
+    """Logical trajectory overlay."""
+
+    points: tuple[LatLon, ...] = ()
+    timestamps: tuple[float, ...] | None = None
+    color: Color = (255, 180, 60, 255)
+    thickness: float = 2.0
+    show_points: bool = False
+    point_stride: int = 1
+
+
+@dataclass(slots=True)
+class LayerState:
+    """Logical layer visibility and ordering state."""
+
+    name: str
+    z_index: int = 0
+    show: bool = True
+    overlay_tags: set[Tag] = field(default_factory=set)

src/dpg_map/projection.py

@@ -0,0 +1,92 @@
+"""Web Mercator projection helpers."""
+
+from __future__ import annotations
+
+import math
+
+from .exceptions import ProjectionError
+from .types import LatLon, Point
+
+WEB_MERCATOR_MAX_LAT = 85.05112878
+DEFAULT_TILE_SIZE = 256
+
+
+def clamp_latitude(lat: float) -> float:
+    """Clamp latitude to the Web Mercator representable range."""
+
+    return min(max(lat, -WEB_MERCATOR_MAX_LAT), WEB_MERCATOR_MAX_LAT)
+
+
+def map_size(zoom: int, tile_size: int = DEFAULT_TILE_SIZE) -> int:
+    """Return square pixel size of the full world at a zoom level."""
+
+    if zoom < 0:
+        raise ProjectionError("zoom must be >= 0")
+    if tile_size <= 0:
+        raise ProjectionError("tile_size must be > 0")
+    return tile_size * (2**zoom)
+
+
+def latlon_to_world(lat: float, lon: float, zoom: int, tile_size: int = DEFAULT_TILE_SIZE) -> Point:
+    """Project latitude/longitude to world pixel coordinates."""
+
+    size = map_size(zoom, tile_size)
+    lat = clamp_latitude(lat)
+    lon = ((lon + 180.0) % 360.0) - 180.0
+
+    sin_lat = math.sin(math.radians(lat))
+    x = (lon + 180.0) / 360.0 * size
+    y = (0.5 - math.log((1.0 + sin_lat) / (1.0 - sin_lat)) / (4.0 * math.pi)) * size
+    return (x, y)
+
+
+def world_to_latlon(x: float, y: float, zoom: int, tile_size: int = DEFAULT_TILE_SIZE) -> LatLon:
+    """Unproject world pixel coordinates to latitude/longitude."""
+
+    size = map_size(zoom, tile_size)
+    lon = x / size * 360.0 - 180.0
+    n = math.pi - 2.0 * math.pi * y / size
+    lat = math.degrees(math.atan(math.sinh(n)))
+    return (lat, lon)
+
+
+def latlon_to_tile(lat: float, lon: float, zoom: int) -> tuple[int, int, int]:
+    """Return the XYZ tile coordinate containing a latitude/longitude point."""
+
+    x, y = latlon_to_world(lat, lon, zoom)
+    scale = 2**zoom
+    tile_x = min(max(int(x // DEFAULT_TILE_SIZE), 0), scale - 1)
+    tile_y = min(max(int(y // DEFAULT_TILE_SIZE), 0), scale - 1)
+    return (tile_x, tile_y, zoom)
+
+
+def world_to_screen(
+    world_x: float,
+    world_y: float,
+    *,
+    center: LatLon,
+    zoom: int,
+    width: int,
+    height: int,
+    tile_size: int = DEFAULT_TILE_SIZE,
+) -> Point:
+    """Convert world pixels to screen pixels for a centered viewport."""
+
+    center_x, center_y = latlon_to_world(center[0], center[1], zoom, tile_size)
+    return (world_x - center_x + width / 2.0, world_y - center_y + height / 2.0)
+
+
+def screen_to_world(
+    screen_x: float,
+    screen_y: float,
+    *,
+    center: LatLon,
+    zoom: int,
+    width: int,
+    height: int,
+    tile_size: int = DEFAULT_TILE_SIZE,
+) -> Point:
+    """Convert screen pixels to world pixels for a centered viewport."""
+
+    center_x, center_y = latlon_to_world(center[0], center[1], zoom, tile_size)
+    return (screen_x + center_x - width / 2.0, screen_y + center_y - height / 2.0)

src/dpg_map/providers.py

@@ -0,0 +1,145 @@
+"""Tile provider definitions and registry."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from string import Formatter
+from threading import RLock
+
+from .exceptions import InvalidProviderError, ProviderExistsError, ProviderNotFoundError
+
+_REQUIRED_TEMPLATE_FIELDS = frozenset({"x", "y", "z"})
+_OPTIONAL_TEMPLATE_FIELDS = frozenset({"s", "r", "ext"})
+
+
+@dataclass(frozen=True, slots=True)
+class TileProvider:
+    """XYZ raster tile provider definition."""
+
+    name: str
+    url_template: str
+    min_zoom: int = 0
+    max_zoom: int = 19
+    tile_size: int = 256
+    attribution: str = ""
+    headers: dict[str, str] = field(default_factory=dict)
+    subdomains: tuple[str, ...] = ()
+    retina: bool = False
+    file_extension: str | None = None
+
+    def __post_init__(self) -> None:
+        name = self.name.strip()
+        if not name:
+            raise InvalidProviderError("provider name must not be empty")
+        if name != self.name:
+            object.__setattr__(self, "name", name)
+
+        if not self.url_template.strip():
+            raise InvalidProviderError("provider url_template must not be empty")
+
+        fields = {
+            field_name
+            for _, field_name, _, _ in Formatter().parse(self.url_template)
+            if field_name is not None and field_name != ""
+        }
+        missing = _REQUIRED_TEMPLATE_FIELDS - fields
+        if missing:
+            missing_text = ", ".join(sorted(missing))
+            raise InvalidProviderError(f"provider url_template missing field(s): {missing_text}")
+
+        unknown = fields - _REQUIRED_TEMPLATE_FIELDS - _OPTIONAL_TEMPLATE_FIELDS
+        if unknown:
+            unknown_text = ", ".join(sorted(unknown))
+            raise InvalidProviderError(
+                f"provider url_template contains unknown field(s): {unknown_text}"
+            )
+
+        if self.min_zoom < 0:
+            raise InvalidProviderError("provider min_zoom must be >= 0")
+        if self.max_zoom < self.min_zoom:
+            raise InvalidProviderError("provider max_zoom must be >= min_zoom")
+        if self.tile_size <= 0:
+            raise InvalidProviderError("provider tile_size must be > 0")
+
+        object.__setattr__(self, "headers", dict(self.headers))
+        object.__setattr__(self, "subdomains", tuple(self.subdomains))
+
+    def build_url(self, *, x: int, y: int, z: int) -> str:
+        """Build a concrete tile URL for an XYZ tile coordinate."""
+
+        if z < self.min_zoom or z > self.max_zoom:
+            raise InvalidProviderError(
+                f"zoom {z} is outside provider range {self.min_zoom}-{self.max_zoom}"
+            )
+
+        subdomain = ""
+        if self.subdomains:
+            subdomain = self.subdomains[(x + y + z) % len(self.subdomains)]
+
+        retina_suffix = "@2x" if self.retina else ""
+        extension = self.file_extension or ""
+        return self.url_template.format(
+            x=x,
+            y=y,
+            z=z,
+            s=subdomain,
+            r=retina_suffix,
+            ext=extension,
+        )
+
+
+OSM = TileProvider(
+    name="osm",
+    url_template="https://tile.openstreetmap.org/{z}/{x}/{y}.png",
+    min_zoom=0,
+    max_zoom=19,
+    tile_size=256,
+    attribution="\u00a9 OpenStreetMap contributors",
+)
+
+_providers: dict[str, TileProvider] = {OSM.name: OSM}
+_providers_lock = RLock()
+
+
+def register_provider(provider: TileProvider, *, replace: bool = False) -> None:
+    """Register a tile provider by name."""
+
+    if not isinstance(provider, TileProvider):
+        raise InvalidProviderError("provider must be a TileProvider")
+
+    with _providers_lock:
+        if provider.name in _providers and not replace:
+            raise ProviderExistsError(f"provider already registered: {provider.name}")
+        _providers[provider.name] = provider
+
+
+def unregister_provider(name: str) -> None:
+    """Remove a registered tile provider."""
+
+    with _providers_lock:
+        if name not in _providers:
+            raise ProviderNotFoundError(f"provider not registered: {name}")
+        del _providers[name]
+
+
+def get_provider(name: str) -> TileProvider:
+    """Return a registered tile provider."""
+
+    with _providers_lock:
+        try:
+            return _providers[name]
+        except KeyError as exc:
+            raise ProviderNotFoundError(f"provider not registered: {name}") from exc
+
+
+def get_default_provider() -> TileProvider:
+    """Return the default OpenStreetMap provider."""
+
+    return get_provider(OSM.name)
+
+
+def list_providers() -> list[str]:
+    """List registered provider names in stable sorted order."""
+
+    with _providers_lock:
+        return sorted(_providers)

src/dpg_map/renderer.py

@@ -0,0 +1,490 @@
+"""GUI-thread renderer implementation."""
+
+from __future__ import annotations
+
+from collections.abc import Callable
+from dataclasses import replace
+from typing import Any
+
+from .commands import CommandKind, MapCommand
+from .draw_layers import DrawLayerTags, clear_draw_layer, ensure_draw_layers
+from .interaction import HitRect, calculate_hit_rect, update_drag_from_button_state
+from .overlays import MarkerOverlay, Overlay, PolylineOverlay, TrajectoryOverlay
+from .projection import latlon_to_world
+from .sizing import SizeMeasurement, apply_size_measurement
+from .state import DirtyFlags, MapState
+from .tiles import Tile, VisibleTile
+from .types import Color, LatLon
+
+
+class MapRenderer:
+    """GUI-thread renderer for the map widget shell and tile layer."""
+
+    def __init__(self, state: MapState, dpg: Any) -> None:
+        self.state = state
+        self._dpg = dpg
+        self._layers: DrawLayerTags | None = None
+        self.last_drained_commands: tuple[MapCommand, ...] = ()
+        self.last_hit_rect: HitRect | None = None
+        self.last_overlay_count: int = 0
+
+    def schedule_next_frame(self) -> None:
+        """Schedule this renderer to run on the next Dear PyGui frame."""
+
+        with self.state.lock:
+            if self.state.frame_scheduled:
+                return
+            self.state.frame_scheduled = True
+        frame = self._dpg.get_frame_count() + 1
+        self._dpg.set_frame_callback(frame, self._frame_callback)
+
+    def _frame_callback(self, sender: Any | None = None, app_data: Any | None = None) -> None:
+        _ = (sender, app_data)
+        with self.state.lock:
+            self.state.frame_scheduled = False
+        if not self._dpg.does_item_exist(self.state.drawlist_tag):
+            return
+        self.render_frame()
+        self.schedule_next_frame()
+
+    def render_frame(self) -> None:
+        """Drain pending commands, refresh size, process tiles, and redraw."""
+
+        commands = drain_renderer_commands(self.state)
+        self.last_drained_commands = tuple(commands)
+        self._update_size_from_dpg()
+        self._poll_mouse_drag()
+
+        with self.state.lock:
+            dirty = self.state.dirty
+            draw_tiles = bool(dirty & (DirtyFlags.SIZE | DirtyFlags.TILES | DirtyFlags.PROVIDER))
+            draw_overlays = bool(dirty & (DirtyFlags.SIZE | DirtyFlags.OVERLAYS))
+            visible = self.state.is_visible
+            width = self.state.measured_width or self.state.last_nonzero_width
+            height = self.state.measured_height or self.state.last_nonzero_height
+            provider_attribution = self.state.provider.attribution
+            provider = self.state.provider
+            center = self.state.center
+            zoom = self.state.zoom
+            generation = self.state.generation
+            cache_dir = self.state.cache_dir
+            overlays = tuple(
+                _copy_overlay_for_render(overlay) for overlay in self.state.overlays.values()
+            )
+            layers = {
+                name: (layer.show, layer.z_index) for name, layer in self.state.layers.items()
+            }
+            self.state.dirty = DirtyFlags.NONE
+
+        accepted_tiles = self.state.tile_manager.drain_results(
+            generation=generation,
+            provider_name=provider.name,
+        )
+        self._delete_evicted_textures()
+        for tile in accepted_tiles:
+            self._ensure_texture(tile)
+
+        visible_tiles: list[VisibleTile] = []
+        if visible and width > 0 and height > 0:
+            visible_tiles = self.state.tile_manager.request_visible_tiles(
+                center=center,
+                zoom=zoom,
+                width=width,
+                height=height,
+                provider=provider,
+                generation=generation,
+                cache_dir=cache_dir,
+                margin=self._prefetch_margin(),
+            )
+
+        if visible and (draw_tiles or accepted_tiles):
+            self._draw_tile_layer(
+                visible_tiles=visible_tiles,
+                width=width,
+                height=height,
+                attribution=provider_attribution,
+                tile_size=provider.tile_size,
+            )
+        if visible and draw_overlays:
+            self._draw_overlay_layer(
+                overlays=overlays,
+                layers=layers,
+                center=center,
+                zoom=zoom,
+                width=width,
+                height=height,
+                tile_size=provider.tile_size,
+            )
+
+    def _update_size_from_dpg(self) -> None:
+        width, height = self._measure_child_content()
+        visible = bool(self._dpg.is_item_shown(self.state.child_window_tag))
+        with self.state.lock:
+            update = apply_size_measurement(
+                self.state,
+                SizeMeasurement(width=width, height=height, visible=visible),
+            )
+            draw_width = update.effective_width
+            draw_height = update.effective_height
+        self._dpg.configure_item(self.state.drawlist_tag, width=draw_width, height=draw_height)
+        draw_pos = tuple(
+            float(value) for value in self._dpg.get_item_rect_min(self.state.drawlist_tag)
+        )
+        with self.state.lock:
+            self.last_hit_rect = calculate_hit_rect(self.state, (draw_pos[0], draw_pos[1]))
+
+    def _poll_mouse_drag(self) -> None:
+        if self.last_hit_rect is None:
+            return
+        try:
+            is_down = bool(self._dpg.is_mouse_button_down(self._dpg.mvMouseButton_Left))
+            mouse_pos = self._dpg.get_mouse_pos(local=False)
+        except Exception:
+            return
+        update_drag_from_button_state(
+            self.state,
+            mouse_pos=(float(mouse_pos[0]), float(mouse_pos[1])),
+            hit_rect=self.last_hit_rect,
+            is_down=is_down,
+        )
+
+    def _measure_child_content(self) -> tuple[int, int]:
+        try:
+            width, height = self._dpg.get_item_rect_size(self.state.child_window_tag)
+        except Exception:
+            return (0, 0)
+        return (max(0, int(width)), max(0, int(height)))
+
+    def _draw_tile_layer(
+        self,
+        *,
+        visible_tiles: list[VisibleTile],
+        width: int,
+        height: int,
+        attribution: str,
+        tile_size: int,
+    ) -> None:
+        width = max(1, int(width))
+        height = max(1, int(height))
+        layers = self._ensure_draw_layers()
+        clear_draw_layer(self._dpg, layers.background)
+        clear_draw_layer(self._dpg, layers.tiles)
+        clear_draw_layer(self._dpg, layers.attribution)
+        self._dpg.draw_rectangle(
+            (0, 0),
+            (width, height),
+            parent=layers.background,
+            color=(54, 68, 78, 255),
+            fill=(29, 38, 45, 255),
+        )
+        for visible_tile in visible_tiles:
+            tile = self.state.tile_manager.get_ready_tile(visible_tile.tile_id)
+            if tile is None or tile.texture_tag is None:
+                continue
+            screen_x = visible_tile.screen_x
+            screen_y = visible_tile.screen_y
+            self._dpg.draw_image(
+                tile.texture_tag,
+                (screen_x, screen_y),
+                (screen_x + tile_size, screen_y + tile_size),
+                parent=layers.tiles,
+            )
+        label = attribution or "Map tiles"
+        text_y = max(28, height - 24)
+        self._dpg.draw_text(
+            (12, text_y),
+            label,
+            parent=layers.attribution,
+            color=(172, 184, 192, 255),
+            size=12,
+        )
+
+    def _draw_overlay_layer(
+        self,
+        *,
+        overlays: tuple[Overlay, ...],
+        layers: dict[str, tuple[bool, int]],
+        center: LatLon,
+        zoom: int,
+        width: int,
+        height: int,
+        tile_size: int,
+    ) -> None:
+        draw_layers = self._ensure_draw_layers()
+        clear_draw_layer(self._dpg, draw_layers.overlays)
+        if width <= 0 or height <= 0:
+            self.last_overlay_count = 0
+            return
+
+        center_x, center_y = latlon_to_world(center[0], center[1], zoom, tile_size)
+        visible_overlays = [
+            overlay
+            for overlay in overlays
+            if overlay.show and layers.get(overlay.layer, (True, 0))[0]
+        ]
+        visible_overlays.sort(key=lambda overlay: layers.get(overlay.layer, (True, 0))[1])
+        drawn = 0
+        for overlay in visible_overlays:
+            if isinstance(overlay, MarkerOverlay):
+                self._draw_marker_overlay(
+                    overlay, center_x, center_y, zoom, width, height, tile_size
+                )
+                drawn += 1
+            elif isinstance(overlay, PolylineOverlay):
+                self._draw_polyline_overlay(
+                    overlay,
+                    center_x,
+                    center_y,
+                    zoom,
+                    width,
+                    height,
+                    tile_size,
+                    draw_layers.overlays,
+                )
+                drawn += 1
+            elif isinstance(overlay, TrajectoryOverlay):
+                self._draw_trajectory_overlay(
+                    overlay,
+                    center_x,
+                    center_y,
+                    zoom,
+                    width,
+                    height,
+                    tile_size,
+                    draw_layers.overlays,
+                )
+                drawn += 1
+        self.last_overlay_count = drawn
+
+    def _draw_marker_overlay(
+        self,
+        overlay: MarkerOverlay,
+        center_x: float,
+        center_y: float,
+        zoom: int,
+        width: int,
+        height: int,
+        tile_size: int,
+    ) -> None:
+        layers = self._ensure_draw_layers()
+        x, y = _latlon_to_screen(
+            overlay.lat,
+            overlay.lon,
+            center_x,
+            center_y,
+            zoom,
+            width,
+            height,
+            tile_size,
+        )
+        radius = max(1.0, float(overlay.radius))
+        self._dpg.draw_circle(
+            (x, y),
+            radius,
+            parent=layers.overlays,
+            color=(255, 255, 255, 230),
+            fill=_rgba(overlay.color),
+            thickness=1.5,
+            segments=20,
+        )
+        if overlay.show_label and overlay.label:
+            self._dpg.draw_text(
+                (x + radius + 4.0, y - 7.0),
+                overlay.label,
+                parent=layers.overlays,
+                color=(245, 248, 250, 255),
+                size=12,
+            )
+
+    def _draw_polyline_overlay(
+        self,
+        overlay: PolylineOverlay,
+        center_x: float,
+        center_y: float,
+        zoom: int,
+        width: int,
+        height: int,
+        tile_size: int,
+        parent: str,
+    ) -> None:
+        points = _screen_points(
+            overlay.points,
+            center_x=center_x,
+            center_y=center_y,
+            zoom=zoom,
+            width=width,
+            height=height,
+            tile_size=tile_size,
+        )
+        if len(points) < 2:
+            return
+        self._dpg.draw_polyline(
+            points,
+            parent=parent,
+            closed=overlay.closed,
+            color=_rgba(overlay.color),
+            thickness=max(1.0, float(overlay.thickness)),
+        )
+
+    def _draw_trajectory_overlay(
+        self,
+        overlay: TrajectoryOverlay,
+        center_x: float,
+        center_y: float,
+        zoom: int,
+        width: int,
+        height: int,
+        tile_size: int,
+        parent: str,
+    ) -> None:
+        points = _screen_points(
+            overlay.points,
+            center_x=center_x,
+            center_y=center_y,
+            zoom=zoom,
+            width=width,
+            height=height,
+            tile_size=tile_size,
+        )
+        if len(points) >= 2:
+            self._dpg.draw_polyline(
+                points,
+                parent=parent,
+                color=_rgba(overlay.color),
+                thickness=max(1.0, float(overlay.thickness)),
+            )
+        if overlay.show_points and points:
+            stride = max(1, int(overlay.point_stride))
+            for point in points[::stride]:
+                self._dpg.draw_circle(
+                    point,
+                    2.5,
+                    parent=parent,
+                    color=_rgba(overlay.color),
+                    fill=_rgba(overlay.color),
+                    segments=8,
+                )
+
+    def _ensure_draw_layers(self) -> DrawLayerTags:
+        if self._layers is None or not self._dpg.does_item_exist(self._layers.overlays):
+            self._layers = ensure_draw_layers(
+                self._dpg,
+                drawlist_tag=self.state.drawlist_tag,
+                map_tag=self.state.tag,
+            )
+        return self._layers
+
+    def _ensure_texture(self, tile: Tile) -> None:
+        if tile.texture_tag is not None:
+            return
+        texture_tag = (
+            f"{self.state.tag}##tile-{tile.tile_id.provider_name}-"
+            f"{tile.tile_id.z}-{tile.tile_id.x}-{tile.tile_id.y}"
+        )
+        if not self._dpg.does_item_exist(texture_tag):
+            self._dpg.add_static_texture(
+                tile.width,
+                tile.height,
+                tile.pixels,
+                tag=texture_tag,
+                parent=self.state.texture_registry_tag,
+            )
+        self.state.tile_manager.set_texture_tag(tile.tile_id, texture_tag)
+
+    def _delete_evicted_textures(self) -> None:
+        for texture_tag in self.state.tile_manager.take_texture_deletions():
+            if self._dpg.does_item_exist(texture_tag):
+                self._dpg.delete_item(texture_tag)
+
+    def _prefetch_margin(self) -> int:
+        from .state import get_config
+
+        return get_config().prefetch_margin_tiles
+
+
+def drain_renderer_commands(state: MapState) -> list[MapCommand]:
+    """Drain and apply GUI-thread command side effects."""
+
+    commands = state.command_queue.drain()
+    if not commands:
+        return []
+
+    with state.lock:
+        for command in commands:
+            if command.kind is CommandKind.SET_VIEW:
+                state.dirty |= DirtyFlags.VIEW | DirtyFlags.TILES | DirtyFlags.OVERLAYS
+            elif command.kind is CommandKind.SET_PROVIDER:
+                state.tile_manager.clear_memory_cache()
+                state.dirty |= DirtyFlags.PROVIDER | DirtyFlags.TILES | DirtyFlags.OVERLAYS
+            elif command.kind in {
+                CommandKind.ADD_OVERLAY,
+                CommandKind.UPDATE_OVERLAY,
+                CommandKind.DELETE_OVERLAY,
+                CommandKind.SET_LAYER_VISIBILITY,
+                CommandKind.ADD_LAYER,
+                CommandKind.CLEAR_LAYER,
+            }:
+                state.dirty |= DirtyFlags.OVERLAYS
+            elif command.kind is CommandKind.CLEAR_MAP:
+                state.tile_manager.clear_memory_cache()
+                state.dirty |= DirtyFlags.TILES | DirtyFlags.OVERLAYS
+            elif command.kind is CommandKind.CLEAR_MEMORY_CACHE:
+                state.tile_manager.clear_memory_cache()
+                state.dirty |= DirtyFlags.TILES
+            elif command.kind is CommandKind.CLEAR_DISK_CACHE:
+                provider = command.payload.get("provider")
+                if not isinstance(provider, str):
+                    provider = None
+                state.tile_manager.clear_disk_cache(state.cache_dir, provider=provider)
+                state.dirty |= DirtyFlags.TILES
+    return commands
+
+
+def make_frame_pump(state: MapState, dpg: Any) -> Callable[[], None]:
+    """Create and attach a renderer frame pump for a map state."""
+
+    renderer = MapRenderer(state, dpg)
+    with state.lock:
+        state.renderer = renderer
+    renderer.schedule_next_frame()
+    return renderer.render_frame
+
+
+def _rgba(color: Color) -> tuple[int, int, int, int]:
+    if len(color) == 3:
+        return (int(color[0]), int(color[1]), int(color[2]), 255)
+    return (int(color[0]), int(color[1]), int(color[2]), int(color[3]))
+
+
+def _latlon_to_screen(
+    lat: float,
+    lon: float,
+    center_x: float,
+    center_y: float,
+    zoom: int,
+    width: int,
+    height: int,
+    tile_size: int,
+) -> tuple[float, float]:
+    world_x, world_y = latlon_to_world(lat, lon, zoom, tile_size)
+    return (world_x - center_x + width / 2.0, world_y - center_y + height / 2.0)
+
+
+def _screen_points(
+    points: tuple[LatLon, ...],
+    *,
+    center_x: float,
+    center_y: float,
+    zoom: int,
+    width: int,
+    height: int,
+    tile_size: int,
+) -> list[tuple[float, float]]:
+    return [
+        _latlon_to_screen(lat, lon, center_x, center_y, zoom, width, height, tile_size)
+        for lat, lon in points
+    ]
+
+
+def _copy_overlay_for_render(overlay: Overlay) -> Overlay:
+    return replace(overlay)

src/dpg_map/sizing.py

@@ -0,0 +1,87 @@
+"""Map sizing measurement helpers."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+from .state import DirtyFlags, MapState, mark_dirty
+
+
+@dataclass(frozen=True, slots=True)
+class SizeMeasurement:
+    """Concrete size and visibility reported by the GUI thread."""
+
+    width: int
+    height: int
+    visible: bool
+
+
+@dataclass(frozen=True, slots=True)
+class SizeUpdate:
+    """Result of applying one GUI size measurement."""
+
+    changed: bool
+    became_visible: bool
+    became_hidden: bool
+    effective_width: int
+    effective_height: int
+
+
+def normalize_dimension(value: int | float | None) -> int:
+    """Convert Dear PyGui size values to stable integer pixels."""
+
+    if value is None:
+        return 0
+    return max(0, int(value))
+
+
+def effective_draw_size(state: MapState) -> tuple[int, int]:
+    """Return the size the drawlist should use for the current frame."""
+
+    width = state.measured_width or state.last_nonzero_width or 1
+    height = state.measured_height or state.last_nonzero_height or 1
+    return (max(1, width), max(1, height))
+
+
+def apply_size_measurement(
+    state: MapState,
+    measurement: SizeMeasurement,
+    *,
+    mark: bool = True,
+) -> SizeUpdate:
+    """Apply a GUI-thread size measurement to logical state.
+
+    A zero measurement is preserved as the current measured size, but it does not
+    erase the last non-zero size. This keeps hidden maps from permanently
+    collapsing when Dear PyGui reports a temporary zero content region.
+    """
+
+    width = normalize_dimension(measurement.width)
+    height = normalize_dimension(measurement.height)
+    visible = bool(measurement.visible and width > 0 and height > 0)
+
+    previous_width = state.measured_width
+    previous_height = state.measured_height
+    previous_visible = state.is_visible
+
+    changed = previous_width != width or previous_height != height or previous_visible != visible
+
+    state.measured_width = width
+    state.measured_height = height
+    state.is_visible = visible
+    if width > 0:
+        state.last_nonzero_width = width
+    if height > 0:
+        state.last_nonzero_height = height
+
+    if changed and mark:
+        mark_dirty(state, DirtyFlags.SIZE | DirtyFlags.TILES | DirtyFlags.OVERLAYS)
+
+    effective_width, effective_height = effective_draw_size(state)
+    return SizeUpdate(
+        changed=changed,
+        became_visible=visible and not previous_visible,
+        became_hidden=previous_visible and not visible,
+        effective_width=effective_width,
+        effective_height=effective_height,
+    )

src/dpg_map/state.py

@@ -0,0 +1,332 @@
+"""Thread-safe state models and registries."""
+
+from __future__ import annotations
+
+from collections.abc import Iterator
+from contextlib import contextmanager
+from dataclasses import dataclass, field
+from enum import IntFlag, auto
+from pathlib import Path
+from threading import RLock
+from uuid import uuid4
+
+from .commands import MapCommandQueue
+from .exceptions import InvalidProviderError, MapNotFoundError
+from .overlays import LayerState, Overlay
+from .providers import TileProvider, get_default_provider, get_provider
+from .tiles import TileManager
+from .types import LatLon, Tag
+
+
+class DirtyFlags(IntFlag):
+    """Reasons the GUI renderer needs to refresh part of a map."""
+
+    NONE = 0
+    VIEW = auto()
+    TILES = auto()
+    OVERLAYS = auto()
+    SIZE = auto()
+    PROVIDER = auto()
+    FULL = VIEW | TILES | OVERLAYS | SIZE | PROVIDER
+
+
+@dataclass(slots=True)
+class DpgMapConfig:
+    """Global package configuration."""
+
+    user_agent: str | None = None
+    cache_dir: Path | None = None
+    default_provider: str | TileProvider = "osm"
+    memory_cache_max_tiles: int = 512
+    disk_cache_max_bytes: int | None = 2_000_000_000
+    prefetch_margin_tiles: int = 1
+    tile_worker_count: int = 4
+    overlay_update_policy: str = "coalesce"
+    debug: bool = False
+
+
+@dataclass(slots=True)
+class InteractionState:
+    """Logical mouse interaction state."""
+
+    active_drag: bool = False
+    last_mouse_position: tuple[float, float] | None = None
+
+
+def default_layers() -> dict[str, LayerState]:
+    """Return the default logical map layers."""
+
+    layers = [
+        LayerState("background", z_index=0),
+        LayerState("tiles", z_index=10),
+        LayerState("default", z_index=50),
+        LayerState("markers", z_index=60),
+        LayerState("lines", z_index=70),
+        LayerState("trajectories", z_index=80),
+        LayerState("attribution", z_index=100),
+    ]
+    return {layer.name: layer for layer in layers}
+
+
+@dataclass(slots=True)
+class MapState:
+    """Thread-safe logical state for one map widget."""
+
+    tag: Tag
+    child_window_tag: Tag
+    drawlist_tag: Tag
+    texture_registry_tag: Tag
+    handler_registry_tag: Tag
+    requested_width: int = 0
+    requested_height: int = 0
+    requested_autosize_x: bool = False
+    requested_autosize_y: bool = False
+    measured_width: int = 0
+    measured_height: int = 0
+    last_nonzero_width: int = 0
+    last_nonzero_height: int = 0
+    is_visible: bool = False
+    center: LatLon = (0.0, 0.0)
+    zoom: int = 2
+    min_zoom: int = 0
+    max_zoom: int = 19
+    provider: TileProvider = field(default_factory=get_default_provider)
+    overlays: dict[Tag, Overlay] = field(default_factory=dict)
+    layers: dict[str, LayerState] = field(default_factory=default_layers)
+    command_queue: MapCommandQueue = field(default_factory=MapCommandQueue)
+    tile_manager: TileManager = field(default_factory=TileManager)
+    renderer: object | None = None
+    interaction: InteractionState = field(default_factory=InteractionState)
+    lock: RLock = field(default_factory=RLock)
+    dirty: DirtyFlags = DirtyFlags.FULL
+    frame_scheduled: bool = False
+    generation: int = 0
+    cache_dir: Path | None = None
+    user_agent: str | None = None
+
+
+_config = DpgMapConfig()
+_config_lock = RLock()
+_maps: dict[Tag, MapState] = {}
+_maps_lock = RLock()
+_current_map_stack: list[Tag] = []
+_current_map_lock = RLock()
+
+
+def _resolve_provider(provider: str | TileProvider | None) -> TileProvider:
+    if provider is None:
+        with _config_lock:
+            provider = _config.default_provider
+    if isinstance(provider, TileProvider):
+        return provider
+    if isinstance(provider, str):
+        return get_provider(provider)
+    raise InvalidProviderError("provider must be a provider name or TileProvider")
+
+
+def configure_state(
+    *,
+    user_agent: str | None = None,
+    cache_dir: str | Path | None = None,
+    default_provider: str | TileProvider = "osm",
+    memory_cache_max_tiles: int = 512,
+    disk_cache_max_bytes: int | None = 2_000_000_000,
+    prefetch_margin_tiles: int = 1,
+    tile_worker_count: int = 4,
+    overlay_update_policy: str = "coalesce",
+    debug: bool = False,
+) -> None:
+    """Replace global dpg-map configuration."""
+
+    if memory_cache_max_tiles < 0:
+        raise ValueError("memory_cache_max_tiles must be >= 0")
+    if disk_cache_max_bytes is not None and disk_cache_max_bytes < 0:
+        raise ValueError("disk_cache_max_bytes must be >= 0 or None")
+    if prefetch_margin_tiles < 0:
+        raise ValueError("prefetch_margin_tiles must be >= 0")
+    if tile_worker_count < 1:
+        raise ValueError("tile_worker_count must be >= 1")
+    if overlay_update_policy != "coalesce":
+        raise ValueError('overlay_update_policy must be "coalesce"')
+
+    resolved_cache_dir = Path(cache_dir).expanduser() if cache_dir is not None else None
+    _resolve_provider(default_provider)
+    with _config_lock:
+        _config.user_agent = user_agent
+        _config.cache_dir = resolved_cache_dir
+        _config.default_provider = default_provider
+        _config.memory_cache_max_tiles = memory_cache_max_tiles
+        _config.disk_cache_max_bytes = disk_cache_max_bytes
+        _config.prefetch_margin_tiles = prefetch_margin_tiles
+        _config.tile_worker_count = tile_worker_count
+        _config.overlay_update_policy = overlay_update_policy
+        _config.debug = debug
+
+
+def get_config() -> DpgMapConfig:
+    """Return a copy of current global configuration."""
+
+    with _config_lock:
+        return DpgMapConfig(
+            user_agent=_config.user_agent,
+            cache_dir=_config.cache_dir,
+            default_provider=_config.default_provider,
+            memory_cache_max_tiles=_config.memory_cache_max_tiles,
+            disk_cache_max_bytes=_config.disk_cache_max_bytes,
+            prefetch_margin_tiles=_config.prefetch_margin_tiles,
+            tile_worker_count=_config.tile_worker_count,
+            overlay_update_policy=_config.overlay_update_policy,
+            debug=_config.debug,
+        )
+
+
+def create_map_state(
+    *,
+    tag: Tag | None = None,
+    center: LatLon = (0.0, 0.0),
+    zoom: int = 2,
+    min_zoom: int | None = None,
+    max_zoom: int | None = None,
+    width: int = 0,
+    height: int = 0,
+    autosize_x: bool = False,
+    autosize_y: bool = False,
+    provider: str | TileProvider | None = None,
+    cache_dir: str | Path | None = None,
+    user_agent: str | None = None,
+) -> MapState:
+    """Create and register a logical map state."""
+
+    map_tag = tag if tag is not None else f"dpg_map_{uuid4().hex}"
+    provider_obj = _resolve_provider(provider)
+    min_zoom_value = provider_obj.min_zoom if min_zoom is None else min_zoom
+    max_zoom_value = provider_obj.max_zoom if max_zoom is None else max_zoom
+    if min_zoom_value < provider_obj.min_zoom:
+        min_zoom_value = provider_obj.min_zoom
+    if max_zoom_value > provider_obj.max_zoom:
+        max_zoom_value = provider_obj.max_zoom
+    if max_zoom_value < min_zoom_value:
+        raise ValueError("max_zoom must be >= min_zoom")
+
+    zoom_value = max(min_zoom_value, min(max_zoom_value, int(zoom)))
+    config = get_config()
+    resolved_cache_dir = Path(cache_dir).expanduser() if cache_dir is not None else config.cache_dir
+    state = MapState(
+        tag=map_tag,
+        child_window_tag=f"{map_tag}##child",
+        drawlist_tag=f"{map_tag}##drawlist",
+        texture_registry_tag=f"{map_tag}##textures",
+        handler_registry_tag=f"{map_tag}##handlers",
+        requested_width=width,
+        requested_height=height,
+        requested_autosize_x=autosize_x,
+        requested_autosize_y=autosize_y,
+        center=(float(center[0]), float(center[1])),
+        zoom=zoom_value,
+        min_zoom=min_zoom_value,
+        max_zoom=max_zoom_value,
+        provider=provider_obj,
+        cache_dir=resolved_cache_dir,
+        user_agent=user_agent if user_agent is not None else config.user_agent,
+    )
+    state.tile_manager = TileManager(
+        memory_cache_max_tiles=config.memory_cache_max_tiles,
+        disk_cache_max_bytes=config.disk_cache_max_bytes,
+        worker_count=config.tile_worker_count,
+        user_agent=state.user_agent,
+    )
+    with _maps_lock:
+        _maps[map_tag] = state
+    return state
+
+
+def register_map_state(state: MapState) -> None:
+    """Register a prebuilt map state."""
+
+    with _maps_lock:
+        _maps[state.tag] = state
+
+
+def unregister_map_state(tag: Tag) -> None:
+    """Remove a map state from the registry."""
+
+    with _maps_lock:
+        _maps.pop(tag, None)
+
+
+def get_map_state(map_tag: Tag | None = None) -> MapState:
+    """Resolve a map by explicit tag or current map context."""
+
+    resolved_tag = resolve_map_tag(map_tag)
+    with _maps_lock:
+        try:
+            return _maps[resolved_tag]
+        except KeyError as exc:
+            raise MapNotFoundError(f"map not registered: {resolved_tag}") from exc
+
+
+def resolve_map_tag(map_tag: Tag | None = None) -> Tag:
+    """Resolve an explicit tag or the current context map tag."""
+
+    if map_tag is not None:
+        return map_tag
+    with _current_map_lock:
+        if _current_map_stack:
+            return _current_map_stack[-1]
+    raise MapNotFoundError("map_tag is required outside a map_widget context")
+
+
+def list_map_states() -> list[MapState]:
+    """Return registered map states as a snapshot."""
+
+    with _maps_lock:
+        return list(_maps.values())
+
+
+def find_map_for_overlay(tag: Tag, map_tag: Tag | None = None) -> MapState:
+    """Find the map containing an overlay, optionally scoped by map tag."""
+
+    if map_tag is not None:
+        return get_map_state(map_tag)
+
+    with _current_map_lock:
+        if _current_map_stack:
+            current = get_map_state(_current_map_stack[-1])
+            with current.lock:
+                if tag in current.overlays:
+                    return current
+
+    matches: list[MapState] = []
+    with _maps_lock:
+        states = list(_maps.values())
+    for state in states:
+        with state.lock:
+            if tag in state.overlays:
+                matches.append(state)
+    if len(matches) == 1:
+        return matches[0]
+    if not matches:
+        raise MapNotFoundError(f"no map contains overlay: {tag}")
+    raise MapNotFoundError(f"overlay tag is ambiguous across maps: {tag}")
+
+
+@contextmanager
+def current_map_context(map_tag: Tag) -> Iterator[None]:
+    """Push a current map tag for context-style overlay creation."""
+
+    with _current_map_lock:
+        _current_map_stack.append(map_tag)
+    try:
+        yield
+    finally:
+        with _current_map_lock:
+            if _current_map_stack and _current_map_stack[-1] == map_tag:
+                _current_map_stack.pop()
+            elif map_tag in _current_map_stack:
+                _current_map_stack.remove(map_tag)
+
+
+def mark_dirty(state: MapState, flags: DirtyFlags) -> None:
+    """Mark a map dirty while holding or acquiring its state lock."""
+
+    state.dirty |= flags

src/dpg_map/tiles.py

@@ -0,0 +1,557 @@
+"""Tile identity, lifecycle, cache, and worker coordination."""
+
+from __future__ import annotations
+
+import warnings
+from dataclasses import dataclass, field
+from enum import Enum
+from io import BytesIO
+from pathlib import Path
+from queue import Empty, Queue
+from threading import Lock, Thread
+from time import time
+from typing import Literal, cast
+
+import requests
+from PIL import Image, UnidentifiedImageError
+
+from .cache import (
+    DiskCacheMetadata,
+    MemoryCacheEntry,
+    MemoryCacheModel,
+    clear_disk_cache_path,
+    prune_disk_cache,
+    tile_cache_path,
+    tile_metadata_path,
+    touch_disk_metadata,
+    write_disk_metadata,
+)
+from .exceptions import CacheError
+from .projection import latlon_to_world, map_size
+from .providers import TileProvider
+from .types import LatLon
+
+
+class TileStatus(Enum):
+    """Lifecycle status for a tile."""
+
+    QUEUED = "queued"
+    LOADING = "loading"
+    READY = "ready"
+    FAILED = "failed"
+
+
+@dataclass(frozen=True, slots=True)
+class TileID:
+    """Provider-namespaced XYZ tile identity."""
+
+    provider_name: str
+    z: int
+    x: int
+    y: int
+
+
+@dataclass(slots=True)
+class Tile:
+    """Decoded tile data plus GUI-thread texture metadata."""
+
+    tile_id: TileID
+    status: TileStatus
+    generation: int
+    width: int = 0
+    height: int = 0
+    pixels: tuple[float, ...] = ()
+    texture_tag: object | None = None
+    source: Literal["memory", "disk", "network"] | None = None
+    error: str | None = None
+    last_accessed_at: float = field(default_factory=time)
+
+
+@dataclass(frozen=True, slots=True)
+class VisibleTile:
+    """A visible tile and its screen-space top-left point."""
+
+    tile_id: TileID
+    screen_x: float
+    screen_y: float
+
+
+@dataclass(frozen=True, slots=True)
+class TileRequest:
+    """Worker-thread tile request."""
+
+    tile_id: TileID
+    generation: int
+    url: str
+    path: Path
+    headers: dict[str, str]
+    disk_cache_max_bytes: int | None
+    protected_paths: frozenset[Path] = frozenset()
+
+
+@dataclass(frozen=True, slots=True)
+class TileResult:
+    """Worker-thread tile result consumed by the GUI thread."""
+
+    tile_id: TileID
+    generation: int
+    status: TileStatus
+    width: int = 0
+    height: int = 0
+    pixels: tuple[float, ...] = ()
+    source: Literal["disk", "network"] | None = None
+    error: str | None = None
+
+
+@dataclass(frozen=True, slots=True)
+class TileManagerSnapshot:
+    """Thread-safe counters for diagnostics."""
+
+    queued_tiles: int
+    loading_tiles: int
+    failed_tiles: int
+    visible_tile_count: int
+    memory_tiles: int
+    memory_hits: int
+    memory_misses: int
+    disk_hits: int
+    disk_misses: int
+    stale_results: int
+
+
+def calculate_visible_tiles(
+    *,
+    center: LatLon,
+    zoom: int,
+    width: int,
+    height: int,
+    provider: TileProvider,
+    margin: int = 0,
+) -> list[VisibleTile]:
+    """Return visible XYZ tiles plus a margin, with wrapped X and clamped Y."""
+
+    if width <= 0 or height <= 0:
+        return []
+    tile_size = provider.tile_size
+    center_x, center_y = latlon_to_world(center[0], center[1], zoom, tile_size)
+    left = center_x - width / 2.0
+    top = center_y - height / 2.0
+    right = center_x + width / 2.0
+    bottom = center_y + height / 2.0
+
+    max_tile = (2**zoom) - 1
+    start_x = int(left // tile_size) - margin
+    end_x = int(right // tile_size) + margin
+    start_y = max(0, int(top // tile_size) - margin)
+    end_y = min(max_tile, int(bottom // tile_size) + margin)
+    world_size = map_size(zoom, tile_size)
+
+    tiles: list[VisibleTile] = []
+    seen: set[TileID] = set()
+    for y in range(start_y, end_y + 1):
+        for raw_x in range(start_x, end_x + 1):
+            x = raw_x % (max_tile + 1)
+            tile_id = TileID(provider.name, zoom, x, y)
+            if tile_id in seen:
+                continue
+            seen.add(tile_id)
+            tile_left = raw_x * tile_size
+            if tile_left < -tile_size:
+                tile_left += world_size
+            screen_x = tile_left - left
+            screen_y = y * tile_size - top
+            tiles.append(VisibleTile(tile_id, screen_x, screen_y))
+    return tiles
+
+
+class TileManager:
+    """Asynchronous tile loader with memory and persistent disk caches."""
+
+    def __init__(
+        self,
+        *,
+        memory_cache_max_tiles: int = 512,
+        disk_cache_max_bytes: int | None = 2_000_000_000,
+        worker_count: int = 4,
+        user_agent: str | None = None,
+    ) -> None:
+        self.memory = MemoryCacheModel(max_tiles=memory_cache_max_tiles)
+        self.disk_cache_max_bytes = disk_cache_max_bytes
+        self.worker_count = worker_count
+        self.user_agent = user_agent
+        self._tiles: dict[TileID, Tile] = {}
+        self._visible_tile_ids: set[TileID] = set()
+        self._queued: set[TileID] = set()
+        self._loading: set[TileID] = set()
+        self._failed: set[TileID] = set()
+        self._request_queue: Queue[TileRequest | None] = Queue()
+        self._result_queue: Queue[TileResult] = Queue()
+        self._threads: list[Thread] = []
+        self._lock = Lock()
+        self._delete_texture_tags: list[object] = []
+        self._disk_hits = 0
+        self._disk_misses = 0
+        self._stale_results = 0
+        self._warned_osm_user_agent = False
+
+    def start(self) -> None:
+        """Start worker threads once."""
+
+        with self._lock:
+            if self._threads:
+                return
+            count = max(1, self.worker_count)
+            for index in range(count):
+                thread = Thread(
+                    target=self._worker_loop,
+                    name=f"dpg-map-tile-worker-{index + 1}",
+                    daemon=True,
+                )
+                self._threads.append(thread)
+                thread.start()
+
+    def stop(self) -> None:
+        """Ask workers to exit."""
+
+        with self._lock:
+            threads = list(self._threads)
+            self._threads.clear()
+        for _ in threads:
+            self._request_queue.put(None)
+
+    def request_visible_tiles(
+        self,
+        *,
+        center: LatLon,
+        zoom: int,
+        width: int,
+        height: int,
+        provider: TileProvider,
+        generation: int,
+        cache_dir: str | Path | None,
+        margin: int,
+    ) -> list[VisibleTile]:
+        """Queue missing visible tiles and return their screen positions."""
+
+        visible = calculate_visible_tiles(
+            center=center,
+            zoom=zoom,
+            width=width,
+            height=height,
+            provider=provider,
+            margin=margin,
+        )
+        visible_ids = {tile.tile_id for tile in visible}
+        with self._lock:
+            self._visible_tile_ids = visible_ids
+            for entry in self.memory.entries.values():
+                entry.protected = entry.tile_id in visible_ids
+
+        self.start()
+        for visible_tile in visible:
+            self._queue_tile(
+                visible_tile.tile_id,
+                provider=provider,
+                generation=generation,
+                cache_dir=cache_dir,
+            )
+        return visible
+
+    def _queue_tile(
+        self,
+        tile_id: TileID,
+        *,
+        provider: TileProvider,
+        generation: int,
+        cache_dir: str | Path | None,
+    ) -> None:
+        with self._lock:
+            tile = self._tiles.get(tile_id)
+            if tile is not None and tile.status is TileStatus.READY:
+                self.memory.record_access(tile_id)
+                tile.last_accessed_at = time()
+                return
+            entry = self.memory.record_access(tile_id)
+            if entry is not None:
+                return
+            if tile_id in self._queued or tile_id in self._loading:
+                return
+            self._queued.add(tile_id)
+            self._tiles[tile_id] = Tile(tile_id, TileStatus.QUEUED, generation=generation)
+
+        headers = dict(provider.headers)
+        if provider.name == "osm":
+            headers = self._headers_with_osm_user_agent(headers)
+        path = tile_cache_path(
+            cache_dir,
+            provider.name,
+            tile_id.z,
+            tile_id.x,
+            tile_id.y,
+            provider.file_extension or "png",
+        )
+        request = TileRequest(
+            tile_id=tile_id,
+            generation=generation,
+            url=provider.build_url(x=tile_id.x, y=tile_id.y, z=tile_id.z),
+            path=path,
+            headers=headers,
+            disk_cache_max_bytes=self.disk_cache_max_bytes,
+            protected_paths=frozenset(path for path in self._visible_disk_paths(cache_dir)),
+        )
+        self._request_queue.put(request)
+
+    def _headers_with_osm_user_agent(self, headers: dict[str, str]) -> dict[str, str]:
+        if any(key.lower() == "user-agent" for key in headers):
+            return headers
+        if self.user_agent:
+            headers["User-Agent"] = self.user_agent
+            return headers
+        with self._lock:
+            should_warn = not self._warned_osm_user_agent
+            self._warned_osm_user_agent = True
+        if should_warn:
+            warnings.warn(
+                "OpenStreetMap tile usage should configure an application-specific user_agent",
+                RuntimeWarning,
+                stacklevel=3,
+            )
+        headers["User-Agent"] = "dpg-map/0.3.0b1"
+        return headers
+
+    def _visible_disk_paths(self, cache_dir: str | Path | None) -> list[Path]:
+        paths: list[Path] = []
+        with self._lock:
+            visible = tuple(self._visible_tile_ids)
+        for tile_id in visible:
+            paths.append(
+                tile_cache_path(
+                    cache_dir,
+                    tile_id.provider_name,
+                    tile_id.z,
+                    tile_id.x,
+                    tile_id.y,
+                )
+            )
+        return paths
+
+    def get_ready_tile(self, tile_id: TileID) -> Tile | None:
+        """Return a ready tile, updating memory LRU metadata."""
+
+        with self._lock:
+            tile = self._tiles.get(tile_id)
+            if tile is None or tile.status is not TileStatus.READY:
+                return None
+            tile.last_accessed_at = time()
+            self.memory.record_access(tile_id)
+            return tile
+
+    def drain_results(self, *, generation: int, provider_name: str) -> list[Tile]:
+        """Accept current-generation results and return ready tiles."""
+
+        accepted: list[Tile] = []
+        while True:
+            try:
+                result = self._result_queue.get_nowait()
+            except Empty:
+                break
+            with self._lock:
+                self._queued.discard(result.tile_id)
+                self._loading.discard(result.tile_id)
+                if result.generation != generation or result.tile_id.provider_name != provider_name:
+                    self._stale_results += 1
+                    continue
+                if result.status is TileStatus.FAILED:
+                    self._failed.add(result.tile_id)
+                    self._tiles[result.tile_id] = Tile(
+                        result.tile_id,
+                        TileStatus.FAILED,
+                        generation=result.generation,
+                        error=result.error,
+                    )
+                    continue
+                tile = Tile(
+                    result.tile_id,
+                    TileStatus.READY,
+                    generation=result.generation,
+                    width=result.width,
+                    height=result.height,
+                    pixels=result.pixels,
+                    source=result.source,
+                )
+                self._tiles[result.tile_id] = tile
+                self.memory.put(
+                    MemoryCacheEntry(
+                        tile_id=result.tile_id,
+                        size_bytes=len(result.pixels) * 4,
+                        protected=result.tile_id in self._visible_tile_ids,
+                        texture_tag=None,
+                    )
+                )
+                accepted.append(tile)
+            self._evict_memory_if_needed()
+        return accepted
+
+    def set_texture_tag(self, tile_id: TileID, texture_tag: object) -> None:
+        """Record a GUI-thread texture tag for a ready tile."""
+
+        with self._lock:
+            tile = self._tiles.get(tile_id)
+            if tile is not None:
+                tile.texture_tag = texture_tag
+            entry = self.memory.entries.get(tile_id)
+            if entry is not None:
+                entry.texture_tag = texture_tag
+
+    def take_texture_deletions(self) -> list[object]:
+        """Return texture tags that must be deleted by the GUI thread."""
+
+        with self._lock:
+            tags = list(self._delete_texture_tags)
+            self._delete_texture_tags.clear()
+            return tags
+
+    def clear_memory_cache(self) -> list[object]:
+        """Clear decoded memory tiles and return texture tags for GUI deletion."""
+
+        with self._lock:
+            tags = [
+                entry.texture_tag
+                for entry in self.memory.entries.values()
+                if entry.texture_tag is not None
+            ]
+            self._delete_texture_tags.extend(tags)
+            self.memory.entries.clear()
+            self._tiles.clear()
+            self._queued.clear()
+            self._loading.clear()
+            self._failed.clear()
+            return tags
+
+    def clear_disk_cache(
+        self, cache_dir: str | Path | None, *, provider: str | None = None
+    ) -> None:
+        """Clear the persistent cache root or one provider namespace."""
+
+        clear_disk_cache_path(cache_dir, provider=provider)
+
+    def snapshot(self) -> TileManagerSnapshot:
+        """Return diagnostic counters."""
+
+        with self._lock:
+            return TileManagerSnapshot(
+                queued_tiles=len(self._queued),
+                loading_tiles=len(self._loading),
+                failed_tiles=len(self._failed),
+                visible_tile_count=len(self._visible_tile_ids),
+                memory_tiles=len(self.memory.entries),
+                memory_hits=self.memory.hits,
+                memory_misses=self.memory.misses,
+                disk_hits=self._disk_hits,
+                disk_misses=self._disk_misses,
+                stale_results=self._stale_results,
+            )
+
+    def _evict_memory_if_needed(self) -> None:
+        with self._lock:
+            evict_ids = self.memory.plan_evictions()
+            for raw_tile_id in evict_ids:
+                tile_id = cast(TileID, raw_tile_id)
+                entry = self.memory.entries.pop(tile_id, None)
+                tile = self._tiles.pop(tile_id, None)
+                texture_tag = None
+                if entry is not None:
+                    texture_tag = entry.texture_tag
+                if texture_tag is None and tile is not None:
+                    texture_tag = tile.texture_tag
+                if texture_tag is not None:
+                    self._delete_texture_tags.append(texture_tag)
+
+    def _worker_loop(self) -> None:
+        while True:
+            request = self._request_queue.get()
+            if request is None:
+                return
+            with self._lock:
+                self._queued.discard(request.tile_id)
+                self._loading.add(request.tile_id)
+                tile = self._tiles.get(request.tile_id)
+                if tile is not None:
+                    tile.status = TileStatus.LOADING
+            result = self._load_tile(request)
+            self._result_queue.put(result)
+
+    def _load_tile(self, request: TileRequest) -> TileResult:
+        try:
+            raw, source = self._read_or_fetch(request)
+            width, height, pixels = decode_tile_image(raw)
+            return TileResult(
+                request.tile_id,
+                request.generation,
+                TileStatus.READY,
+                width=width,
+                height=height,
+                pixels=pixels,
+                source=source,
+            )
+        except Exception as exc:
+            return TileResult(
+                request.tile_id,
+                request.generation,
+                TileStatus.FAILED,
+                error=str(exc),
+            )
+
+    def _read_or_fetch(self, request: TileRequest) -> tuple[bytes, Literal["disk", "network"]]:
+        if request.path.exists():
+            try:
+                raw = request.path.read_bytes()
+                touch_disk_metadata(tile_metadata_path(request.path))
+            except (OSError, CacheError):
+                raw = b""
+            if raw:
+                with self._lock:
+                    self._disk_hits += 1
+                return raw, "disk"
+
+        with self._lock:
+            self._disk_misses += 1
+        response = requests.get(request.url, headers=request.headers, timeout=20)
+        response.raise_for_status()
+        raw = response.content
+        downloaded_at = time()
+        try:
+            request.path.parent.mkdir(parents=True, exist_ok=True)
+            request.path.write_bytes(raw)
+            write_disk_metadata(
+                tile_metadata_path(request.path),
+                DiskCacheMetadata(
+                    url=request.url,
+                    etag=response.headers.get("ETag"),
+                    last_modified=response.headers.get("Last-Modified"),
+                    expires=response.headers.get("Expires"),
+                    downloaded_at=downloaded_at,
+                    last_accessed_at=downloaded_at,
+                    size_bytes=len(raw),
+                ),
+            )
+            prune_disk_cache(
+                request.path.parents[3],
+                request.disk_cache_max_bytes,
+                protected_paths=set(request.protected_paths),
+            )
+        except (OSError, CacheError):
+            pass
+        return raw, "network"
+
+
+def decode_tile_image(raw: bytes) -> tuple[int, int, tuple[float, ...]]:
+    """Decode an image into Dear PyGui-compatible RGBA float data."""
+
+    try:
+        image = Image.open(BytesIO(raw)).convert("RGBA")
+    except UnidentifiedImageError as exc:
+        raise ValueError("tile image data could not be decoded") from exc
+    width, height = image.size
+    pixels = tuple(channel / 255.0 for channel in image.tobytes())
+    return width, height, pixels

src/dpg_map/types.py

@@ -0,0 +1,31 @@
+"""Shared type aliases and small value objects."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import TypeAlias
+
+Tag: TypeAlias = str | int
+LatLon: TypeAlias = tuple[float, float]
+Point: TypeAlias = tuple[float, float]
+Bounds: TypeAlias = tuple[LatLon, LatLon]
+TileCoord: TypeAlias = tuple[int, int, int]
+Color: TypeAlias = tuple[int, int, int] | tuple[int, int, int, int]
+
+
+@dataclass(frozen=True, slots=True)
+class ScreenPoint:
+    """A pixel position in map widget coordinates."""
+
+    x: float
+    y: float
+
+
+@dataclass(frozen=True, slots=True)
+class GeoBounds:
+    """Latitude/longitude bounds with south-west and north-east corners."""
+
+    south: float
+    west: float
+    north: float
+    east: float

src/dpg_map/widget.py

@@ -0,0 +1,129 @@
+"""Dear PyGui map widget construction."""
+
+from __future__ import annotations
+
+from collections.abc import Iterator
+from contextlib import contextmanager
+from pathlib import Path
+from typing import Any
+
+from .interaction import (
+    calculate_hit_rect,
+    handle_mouse_down,
+    handle_mouse_drag,
+    handle_mouse_release,
+    handle_mouse_wheel,
+    wheel_delta_from_app_data,
+)
+from .providers import TileProvider
+from .renderer import MapRenderer
+from .state import create_map_state, current_map_context
+from .types import LatLon, Tag
+
+
+@contextmanager
+def map_widget(
+    *,
+    tag: Tag | None = None,
+    center: LatLon = (0.0, 0.0),
+    zoom: int = 2,
+    provider: str | TileProvider | None = None,
+    width: int = 0,
+    height: int = 0,
+    autosize_x: bool = False,
+    autosize_y: bool = False,
+    **kwargs: object,
+) -> Iterator[Tag | None]:
+    """Create a Dear PyGui child-window map shell and logical map context."""
+
+    cache_dir_value = kwargs.get("cache_dir")
+    cache_dir = cache_dir_value if isinstance(cache_dir_value, str | Path) else None
+    user_agent_value = kwargs.get("user_agent")
+    user_agent = user_agent_value if isinstance(user_agent_value, str) else None
+    state = create_map_state(
+        tag=tag,
+        center=center,
+        zoom=zoom,
+        provider=provider,
+        width=width,
+        height=height,
+        autosize_x=autosize_x,
+        autosize_y=autosize_y,
+        cache_dir=cache_dir,
+        user_agent=user_agent,
+    )
+    import dearpygui.dearpygui as dpg
+
+    child_kwargs: dict[str, Any] = dict(kwargs)
+    child_kwargs.pop("cache_dir", None)
+    child_kwargs.pop("user_agent", None)
+    child_kwargs.setdefault("border", False)
+    child_kwargs.setdefault("no_scrollbar", True)
+    child_kwargs.setdefault("no_scroll_with_mouse", True)
+
+    dpg.add_child_window(
+        tag=state.child_window_tag,
+        width=width,
+        height=height,
+        autosize_x=autosize_x,
+        autosize_y=autosize_y,
+        **child_kwargs,
+    )
+    dpg.add_texture_registry(tag=state.texture_registry_tag)
+    dpg.add_drawlist(1, 1, tag=state.drawlist_tag, parent=state.child_window_tag)
+    dpg.add_handler_registry(tag=state.handler_registry_tag)
+
+    def _mouse_pos() -> tuple[float, float]:
+        pos = dpg.get_mouse_pos(local=False)
+        return (float(pos[0]), float(pos[1]))
+
+    def _hit_rect() -> Any:
+        draw_pos = tuple(float(value) for value in dpg.get_item_rect_min(state.drawlist_tag))
+        return calculate_hit_rect(state, (draw_pos[0], draw_pos[1]))
+
+    def _on_mouse_down(sender: Any, app_data: Any, user_data: Any) -> None:
+        _ = (sender, app_data, user_data)
+        handle_mouse_down(state, _mouse_pos(), _hit_rect())
+
+    def _on_mouse_drag(sender: Any, app_data: Any, user_data: Any) -> None:
+        _ = (sender, app_data, user_data)
+        handle_mouse_drag(state, _mouse_pos())
+
+    def _on_mouse_release(sender: Any, app_data: Any, user_data: Any) -> None:
+        _ = (sender, app_data, user_data)
+        handle_mouse_release(state)
+
+    def _on_mouse_wheel(sender: Any, app_data: Any, user_data: Any) -> None:
+        _ = (sender, user_data)
+        handle_mouse_wheel(
+            state,
+            mouse_pos=_mouse_pos(),
+            wheel_delta=wheel_delta_from_app_data(app_data),
+            hit_rect=_hit_rect(),
+        )
+
+    dpg.add_mouse_down_handler(
+        button=dpg.mvMouseButton_Left,
+        callback=_on_mouse_down,
+        parent=state.handler_registry_tag,
+    )
+    dpg.add_mouse_drag_handler(
+        button=dpg.mvMouseButton_Left,
+        threshold=0.0,
+        callback=_on_mouse_drag,
+        parent=state.handler_registry_tag,
+    )
+    dpg.add_mouse_release_handler(
+        button=dpg.mvMouseButton_Left,
+        callback=_on_mouse_release,
+        parent=state.handler_registry_tag,
+    )
+    dpg.add_mouse_wheel_handler(callback=_on_mouse_wheel, parent=state.handler_registry_tag)
+
+    renderer = MapRenderer(state, dpg)
+    with state.lock:
+        state.renderer = renderer
+    renderer.schedule_next_frame()
+
+    with current_map_context(state.tag):
+        yield state.tag

tests/.gitkeep

@@ -0,0 +1 @@
+

tests/test_cache.py

@@ -0,0 +1,90 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from dpg_map.cache import (
+    CacheStats,
+    DiskCacheConfig,
+    DiskCacheMetadata,
+    MemoryCacheConfig,
+    clear_disk_cache_path,
+    disk_cache_size_bytes,
+    plan_disk_prune,
+    tile_cache_path,
+    write_disk_metadata,
+)
+
+
+def test_cache_stats_dataclass_construction() -> None:
+    stats = CacheStats(
+        memory_tiles=3,
+        memory_max_tiles=512,
+        memory_hits=10,
+        memory_misses=2,
+        disk_bytes=1024,
+        disk_max_bytes=None,
+        disk_hits=7,
+        disk_misses=1,
+        disk_path=Path("/tmp/dpg-map-cache"),
+    )
+
+    assert stats.memory_tiles == 3
+    assert stats.disk_max_bytes is None
+    assert stats.disk_path == Path("/tmp/dpg-map-cache")
+
+
+def test_initial_cache_config_dataclasses() -> None:
+    memory_config = MemoryCacheConfig()
+    disk_config = DiskCacheConfig()
+
+    assert memory_config.max_tiles == 512
+    assert disk_config.max_bytes == 2_000_000_000
+
+
+def test_disk_cache_path_generation(tmp_path: Path) -> None:
+    path = tile_cache_path(tmp_path, "osm", 4, 8, 9, "jpg")
+
+    assert path == tmp_path / "osm" / "4" / "8" / "9.jpg"
+
+
+def test_disk_cache_prune_ordering(tmp_path: Path) -> None:
+    first = tile_cache_path(tmp_path, "osm", 1, 1, 1)
+    second = tile_cache_path(tmp_path, "osm", 1, 1, 2)
+    protected = tile_cache_path(tmp_path, "osm", 1, 1, 3)
+
+    for path, accessed_at in [(first, 1.0), (second, 2.0), (protected, 0.0)]:
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_bytes(b"abcde")
+        write_disk_metadata(
+            path.with_suffix(".json"),
+            DiskCacheMetadata(
+                url=str(path),
+                downloaded_at=accessed_at,
+                last_accessed_at=accessed_at,
+                size_bytes=5,
+            ),
+        )
+
+    planned = plan_disk_prune(tmp_path, 5, protected_paths={protected})
+
+    assert planned == [first, second]
+
+
+def test_provider_scoped_disk_cache_clear(tmp_path: Path) -> None:
+    osm = tile_cache_path(tmp_path, "osm", 1, 1, 1)
+    custom = tile_cache_path(tmp_path, "custom", 1, 1, 1)
+    for path in (osm, custom):
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_bytes(b"abcde")
+        write_disk_metadata(
+            path.with_suffix(".json"),
+            DiskCacheMetadata(url=str(path), last_accessed_at=1.0, size_bytes=5),
+        )
+
+    assert disk_cache_size_bytes(tmp_path, provider="osm") == 5
+
+    clear_disk_cache_path(tmp_path, provider="osm")
+
+    assert not osm.exists()
+    assert custom.exists()
+    assert disk_cache_size_bytes(tmp_path) == 5

tests/test_commands.py

@@ -0,0 +1,35 @@
+from __future__ import annotations
+
+from dpg_map.commands import CommandKind, MapCommand, MapCommandQueue
+
+
+def test_overlay_updates_coalesce_by_overlay_tag() -> None:
+    queue = MapCommandQueue()
+
+    queue.put(MapCommand(CommandKind.UPDATE_OVERLAY, "map", {"tag": "vehicle", "lat": 1.0}))
+    queue.put(MapCommand(CommandKind.UPDATE_OVERLAY, "map", {"tag": "vehicle", "lat": 2.0}))
+    queue.put(MapCommand(CommandKind.UPDATE_OVERLAY, "map", {"tag": "other", "lat": 3.0}))
+
+    drained = queue.drain()
+
+    assert len(drained) == 2
+    assert drained[0].payload == {"tag": "vehicle", "lat": 2.0}
+    assert drained[1].payload == {"tag": "other", "lat": 3.0}
+
+
+def test_latest_view_update_wins_but_structural_commands_keep_order() -> None:
+    queue = MapCommandQueue()
+
+    queue.put(MapCommand(CommandKind.ADD_OVERLAY, "map", {"tag": "a"}))
+    queue.put(MapCommand(CommandKind.SET_VIEW, "map", {"zoom": 3}))
+    queue.put(MapCommand(CommandKind.SET_VIEW, "map", {"zoom": 4}))
+    queue.put(MapCommand(CommandKind.DELETE_OVERLAY, "map", {"tag": "a"}))
+
+    drained = queue.drain()
+
+    assert [command.kind for command in drained] == [
+        CommandKind.ADD_OVERLAY,
+        CommandKind.SET_VIEW,
+        CommandKind.DELETE_OVERLAY,
+    ]
+    assert drained[1].payload == {"zoom": 4}

tests/test_hardening.py

@@ -0,0 +1,140 @@
+from __future__ import annotations
+
+from math import nan
+
+import pytest
+
+import dpg_map as dpgm
+from dpg_map.commands import CommandKind
+from dpg_map.exceptions import (
+    CoordinateError,
+    MapNotFoundError,
+    OverlayNotFoundError,
+    ProviderNotFoundError,
+)
+from dpg_map.overlays import TrajectoryOverlay
+from dpg_map.providers import TileProvider
+from dpg_map.renderer import drain_renderer_commands
+from dpg_map.state import DirtyFlags, InteractionState, create_map_state, get_map_state
+from dpg_map.tiles import TileID, TileResult, TileStatus
+
+
+def test_public_callables_have_docstrings() -> None:
+    for name in dpgm.__all__:
+        value = getattr(dpgm, name)
+        if callable(value):
+            assert value.__doc__, name
+
+
+def test_unknown_map_raises_public_error() -> None:
+    with pytest.raises(MapNotFoundError):
+        dpgm.get_center(map_tag="missing-map")
+
+
+def test_unknown_overlay_raises_public_error() -> None:
+    create_map_state(tag="missing-overlay")
+
+    with pytest.raises(OverlayNotFoundError):
+        dpgm.update_marker("vehicle", lat=47.0, lon=2.0, map_tag="missing-overlay")
+
+
+def test_unknown_provider_raises_public_error() -> None:
+    create_map_state(tag="missing-provider")
+
+    with pytest.raises(ProviderNotFoundError):
+        dpgm.set_provider("missing-provider-name", map_tag="missing-provider")
+
+
+def test_invalid_coordinates_raise_public_error() -> None:
+    create_map_state(tag="invalid-coordinates")
+
+    with pytest.raises(CoordinateError):
+        dpgm.add_marker("bad-lat", lat=91.0, lon=2.0, map_tag="invalid-coordinates")
+    with pytest.raises(CoordinateError):
+        dpgm.set_center(nan, 2.0, map_tag="invalid-coordinates")
+
+
+def test_mismatched_polyline_lat_lon_lengths_raise_public_error() -> None:
+    create_map_state(tag="mismatched-polyline")
+
+    with pytest.raises(CoordinateError):
+        dpgm.add_polyline("line", lats=[47.0, 47.1], lons=[2.0], map_tag="mismatched-polyline")
+
+
+def test_empty_trajectory_is_valid_for_live_updates() -> None:
+    create_map_state(tag="empty-trajectory")
+
+    dpgm.add_trajectory("track", points=[], map_tag="empty-trajectory")
+
+    state = get_map_state("empty-trajectory")
+    overlay = state.overlays["track"]
+    assert isinstance(overlay, TrajectoryOverlay)
+    assert overlay.points == ()
+
+
+def test_clear_deleted_overlay_raises_public_error() -> None:
+    create_map_state(tag="deleted-overlay")
+    dpgm.add_marker("vehicle", lat=47.0, lon=2.0, map_tag="deleted-overlay")
+
+    dpgm.delete_overlay("vehicle", map_tag="deleted-overlay")
+
+    with pytest.raises(OverlayNotFoundError):
+        dpgm.delete_overlay("vehicle", map_tag="deleted-overlay")
+
+
+def test_provider_switch_ignores_tiles_that_finish_after_switch() -> None:
+    provider = TileProvider(
+        name="hardening-switch-provider",
+        url_template="https://tiles.example.test/{z}/{x}/{y}.png",
+        min_zoom=0,
+        max_zoom=4,
+    )
+    dpgm.register_provider(provider)
+    try:
+        state = create_map_state(tag="provider-switch-loading", zoom=3)
+        old_tile = TileID("osm", 3, 1, 2)
+        with state.tile_manager._lock:
+            state.tile_manager._loading.add(old_tile)
+
+        dpgm.set_provider("hardening-switch-provider", map_tag="provider-switch-loading")
+        state.tile_manager._result_queue.put(
+            TileResult(
+                old_tile,
+                generation=0,
+                status=TileStatus.READY,
+                width=1,
+                height=1,
+                pixels=(1.0, 1.0, 1.0, 1.0),
+                source="network",
+            )
+        )
+
+        commands = drain_renderer_commands(state)
+        accepted = state.tile_manager.drain_results(
+            generation=state.generation,
+            provider_name=state.provider.name,
+        )
+
+        assert [command.kind for command in commands] == [CommandKind.SET_PROVIDER]
+        assert accepted == []
+        assert state.tile_manager.snapshot().stale_results == 1
+        assert state.tile_manager.get_ready_tile(old_tile) is None
+    finally:
+        dpgm.unregister_provider("hardening-switch-provider")
+
+
+def test_overlay_update_preserves_active_drag_model_state() -> None:
+    create_map_state(tag="update-while-dragging", center=(47.0, 2.0), zoom=9)
+    dpgm.add_marker("vehicle", lat=47.0, lon=2.0, map_tag="update-while-dragging")
+    state = get_map_state("update-while-dragging")
+    state.command_queue.drain()
+    state.dirty = DirtyFlags.NONE
+    state.interaction = InteractionState(active_drag=True, last_mouse_position=(20.0, 30.0))
+
+    dpgm.update_marker("vehicle", lat=47.1, lon=2.1, map_tag="update-while-dragging")
+
+    assert state.interaction.active_drag is True
+    assert state.interaction.last_mouse_position == (20.0, 30.0)
+    assert state.center == (47.0, 2.0)
+    assert state.zoom == 9
+    assert state.dirty == DirtyFlags.OVERLAYS

tests/test_interaction.py

@@ -0,0 +1,109 @@
+from __future__ import annotations
+
+import pytest
+
+import dpg_map as dpgm
+from dpg_map.commands import CommandKind
+from dpg_map.interaction import (
+    calculate_hit_rect,
+    handle_mouse_down,
+    handle_mouse_drag,
+    handle_mouse_release,
+    handle_mouse_wheel,
+    pan_state_by_pixels,
+    update_drag_from_button_state,
+)
+from dpg_map.sizing import SizeMeasurement, apply_size_measurement
+from dpg_map.state import DirtyFlags, create_map_state, get_map_state
+
+
+def test_hit_rect_uses_effective_map_size() -> None:
+    state = create_map_state(tag="hit-rect")
+    apply_size_measurement(state, SizeMeasurement(width=400, height=250, visible=True))
+
+    rect = calculate_hit_rect(state, (10.0, 20.0))
+
+    assert rect.x == 10.0
+    assert rect.y == 20.0
+    assert rect.width == 400
+    assert rect.height == 250
+    assert rect.contains(410.0, 270.0)
+    assert not rect.contains(411.0, 270.0)
+
+
+def test_pan_updates_center_and_queues_view_command() -> None:
+    state = create_map_state(tag="pan", center=(0.0, 0.0), zoom=3)
+    apply_size_measurement(state, SizeMeasurement(width=400, height=300, visible=True))
+
+    old_center = state.center
+    pan_state_by_pixels(state, 40.0, 0.0)
+
+    assert state.center != old_center
+    assert state.center[1] < old_center[1]
+    assert state.dirty & DirtyFlags.VIEW
+    drained = state.command_queue.drain()
+    assert drained[-1].kind is CommandKind.SET_VIEW
+    assert drained[-1].payload["center"] == state.center
+
+
+def test_mouse_drag_uses_active_drag_state() -> None:
+    state = create_map_state(tag="drag", center=(0.0, 0.0), zoom=3)
+    apply_size_measurement(state, SizeMeasurement(width=400, height=300, visible=True))
+    rect = calculate_hit_rect(state, (10.0, 20.0))
+
+    handle_mouse_down(state, (20.0, 30.0), rect)
+    assert state.interaction.active_drag is True
+    handle_mouse_drag(state, (45.0, 30.0))
+    handle_mouse_release(state)
+
+    assert state.interaction.active_drag is False
+    assert state.interaction.last_mouse_position is None
+    assert state.center[1] < 0.0
+
+
+def test_polled_drag_starts_and_moves_while_button_is_down() -> None:
+    state = create_map_state(tag="polled-drag", center=(0.0, 0.0), zoom=3)
+    apply_size_measurement(state, SizeMeasurement(width=400, height=300, visible=True))
+    rect = calculate_hit_rect(state, (10.0, 20.0))
+
+    update_drag_from_button_state(state, mouse_pos=(20.0, 30.0), hit_rect=rect, is_down=True)
+    update_drag_from_button_state(state, mouse_pos=(45.0, 30.0), hit_rect=rect, is_down=True)
+    update_drag_from_button_state(state, mouse_pos=(45.0, 30.0), hit_rect=rect, is_down=False)
+
+    assert state.interaction.active_drag is False
+    assert state.center[1] < 0.0
+
+
+def test_wheel_zoom_keeps_cursor_latlon_stable() -> None:
+    state = create_map_state(tag="wheel", center=(47.9029, 1.9093), zoom=8)
+    apply_size_measurement(state, SizeMeasurement(width=800, height=600, visible=True))
+    rect = calculate_hit_rect(state, (100.0, 50.0))
+
+    before = dpgm.screen_to_latlon(300.0, 200.0, map_tag="wheel")
+    handle_mouse_wheel(state, mouse_pos=(400.0, 250.0), wheel_delta=1.0, hit_rect=rect)
+    after = dpgm.screen_to_latlon(300.0, 200.0, map_tag="wheel")
+
+    assert state.zoom == 9
+    assert after == pytest.approx(before, abs=1e-7)
+
+
+def test_view_coordinate_helpers_roundtrip() -> None:
+    create_map_state(tag="view-roundtrip", center=(47.9029, 1.9093), zoom=12)
+    state = get_map_state("view-roundtrip")
+    apply_size_measurement(state, SizeMeasurement(width=800, height=600, visible=True))
+
+    screen = dpgm.latlon_to_screen(47.91, 1.92, map_tag="view-roundtrip")
+    latlon = dpgm.screen_to_latlon(*screen, map_tag="view-roundtrip")
+
+    assert latlon == pytest.approx((47.91, 1.92), abs=1e-7)
+
+
+def test_fit_bounds_sets_center_and_zoom() -> None:
+    create_map_state(tag="fit", center=(0.0, 0.0), zoom=2)
+    state = get_map_state("fit")
+    apply_size_measurement(state, SizeMeasurement(width=800, height=600, visible=True))
+
+    dpgm.fit_bounds(((47.8, 1.8), (48.0, 2.0)), map_tag="fit")
+
+    assert dpgm.get_center(map_tag="fit") == pytest.approx((47.9, 1.9))
+    assert dpgm.get_zoom(map_tag="fit") > 2

tests/test_overlays_state.py

@@ -0,0 +1,113 @@
+from __future__ import annotations
+
+from threading import Thread
+
+import pytest
+
+import dpg_map as dpgm
+from dpg_map.commands import CommandKind
+from dpg_map.exceptions import CoordinateError
+from dpg_map.overlays import TrajectoryOverlay
+from dpg_map.state import DirtyFlags, create_map_state, get_map_state
+
+
+def test_overlay_update_does_not_alter_center_or_zoom() -> None:
+    create_map_state(tag="overlay-isolation", center=(47.0, 2.0), zoom=8)
+    dpgm.add_marker("vehicle", lat=47.1, lon=2.1, map_tag="overlay-isolation")
+
+    before_center = dpgm.get_center(map_tag="overlay-isolation")
+    before_zoom = dpgm.get_zoom(map_tag="overlay-isolation")
+
+    dpgm.update_marker("vehicle", lat=47.2, lon=2.2, map_tag="overlay-isolation")
+
+    assert dpgm.get_center(map_tag="overlay-isolation") == before_center
+    assert dpgm.get_zoom(map_tag="overlay-isolation") == before_zoom
+    state = get_map_state("overlay-isolation")
+    assert state.dirty & DirtyFlags.OVERLAYS
+
+
+def test_trajectory_inputs_are_copied() -> None:
+    create_map_state(tag="trajectory-copy")
+    lats = [1.0, 2.0]
+    lons = [3.0, 4.0]
+
+    dpgm.add_trajectory("track", lats=lats, lons=lons, map_tag="trajectory-copy")
+    lats[0] = 99.0
+    lons[0] = 99.0
+
+    state = get_map_state("trajectory-copy")
+    overlay = state.overlays["track"]
+
+    assert isinstance(overlay, TrajectoryOverlay)
+    assert overlay.points == ((1.0, 3.0), (2.0, 4.0))
+
+
+def test_mismatched_lat_lon_lengths_raise() -> None:
+    create_map_state(tag="bad-coordinates")
+
+    with pytest.raises(CoordinateError):
+        dpgm.add_trajectory("track", lats=[1.0], lons=[2.0, 3.0], map_tag="bad-coordinates")
+
+
+def test_layer_state_tracks_visibility_and_overlay_membership() -> None:
+    create_map_state(tag="layers")
+
+    dpgm.add_layer("fleet", map_tag="layers")
+    dpgm.add_marker("vehicle", lat=1.0, lon=2.0, layer="fleet", map_tag="layers")
+    dpgm.hide_layer("fleet", map_tag="layers")
+
+    state = get_map_state("layers")
+    assert state.layers["fleet"].show is False
+    assert state.layers["fleet"].overlay_tags == {"vehicle"}
+
+    dpgm.clear_layer("fleet", map_tag="layers")
+
+    assert state.layers["fleet"].overlay_tags == set()
+    assert "vehicle" not in state.overlays
+
+
+def test_add_layer_can_update_visibility_and_z_index() -> None:
+    create_map_state(tag="layer-order")
+
+    dpgm.add_layer("fleet", z_index=25, show=False, map_tag="layer-order")
+    dpgm.add_layer("fleet", z_index=30, show=True, map_tag="layer-order")
+
+    state = get_map_state("layer-order")
+    assert state.layers["fleet"].show is True
+    assert state.layers["fleet"].z_index == 30
+
+
+def test_threaded_marker_updates_coalesce_without_touching_view_or_drag_state() -> None:
+    create_map_state(tag="threaded-marker", center=(47.0, 2.0), zoom=9)
+    dpgm.add_marker("vehicle", lat=47.0, lon=2.0, map_tag="threaded-marker")
+    state = get_map_state("threaded-marker")
+    state.command_queue.drain()
+    state.dirty = DirtyFlags.NONE
+    state.interaction.active_drag = True
+    state.interaction.last_mouse_position = (100.0, 100.0)
+    before_center = state.center
+    before_zoom = state.zoom
+
+    def update_worker(offset: float) -> None:
+        for index in range(100):
+            dpgm.update_marker(
+                "vehicle",
+                lat=47.0 + offset,
+                lon=2.0 + index * 0.00001,
+                map_tag="threaded-marker",
+            )
+
+    threads = [Thread(target=update_worker, args=(worker * 0.0001,)) for worker in range(4)]
+    for thread in threads:
+        thread.start()
+    for thread in threads:
+        thread.join()
+
+    commands = state.command_queue.drain()
+
+    assert state.center == before_center
+    assert state.zoom == before_zoom
+    assert state.interaction.active_drag is True
+    assert state.interaction.last_mouse_position == (100.0, 100.0)
+    assert state.dirty == DirtyFlags.OVERLAYS
+    assert [command.kind for command in commands] == [CommandKind.UPDATE_OVERLAY]

tests/test_projection.py

@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+import pytest
+
+from dpg_map.projection import (
+    WEB_MERCATOR_MAX_LAT,
+    clamp_latitude,
+    latlon_to_tile,
+    latlon_to_world,
+    screen_to_world,
+    world_to_latlon,
+    world_to_screen,
+)
+
+
+@pytest.mark.parametrize(
+    ("lat", "lon", "zoom"),
+    [
+        (0.0, 0.0, 0),
+        (47.9029, 1.9093, 15),
+        (-33.8688, 151.2093, 10),
+        (WEB_MERCATOR_MAX_LAT, 179.999, 4),
+    ],
+)
+def test_projection_roundtrip(lat: float, lon: float, zoom: int) -> None:
+    x, y = latlon_to_world(lat, lon, zoom)
+    roundtrip_lat, roundtrip_lon = world_to_latlon(x, y, zoom)
+
+    assert roundtrip_lat == pytest.approx(clamp_latitude(lat), abs=1e-7)
+    assert roundtrip_lon == pytest.approx(lon, abs=1e-7)
+
+
+def test_latlon_to_tile_returns_xyz_coordinate() -> None:
+    assert latlon_to_tile(0.0, 0.0, 1) == (1, 1, 1)
+
+
+def test_world_screen_roundtrip() -> None:
+    center = (47.9029, 1.9093)
+    world = latlon_to_world(47.91, 1.92, 14)
+    screen = world_to_screen(*world, center=center, zoom=14, width=800, height=600)
+
+    assert screen_to_world(*screen, center=center, zoom=14, width=800, height=600) == pytest.approx(
+        world
+    )

tests/test_providers.py

@@ -0,0 +1,71 @@
+from __future__ import annotations
+
+import pytest
+
+import dpg_map as dpgm
+from dpg_map.exceptions import InvalidProviderError, ProviderExistsError, ProviderNotFoundError
+
+
+def test_default_provider_is_registered() -> None:
+    provider = dpgm.get_provider("osm")
+
+    assert provider.name == "osm"
+    assert "osm" in dpgm.list_providers()
+    assert provider.build_url(x=1, y=2, z=3) == "https://tile.openstreetmap.org/3/1/2.png"
+
+
+def test_provider_registration_roundtrip() -> None:
+    provider = dpgm.TileProvider(
+        name="unit-test-provider",
+        url_template="https://tiles.example.test/{z}/{x}/{y}.png",
+        attribution="Example",
+    )
+
+    dpgm.register_provider(provider)
+    try:
+        assert dpgm.get_provider("unit-test-provider") == provider
+        assert "unit-test-provider" in dpgm.list_providers()
+    finally:
+        dpgm.unregister_provider("unit-test-provider")
+
+    with pytest.raises(ProviderNotFoundError):
+        dpgm.get_provider("unit-test-provider")
+
+
+def test_duplicate_provider_registration_fails() -> None:
+    provider = dpgm.TileProvider(
+        name="unit-test-duplicate",
+        url_template="https://tiles.example.test/{z}/{x}/{y}.png",
+    )
+
+    dpgm.register_provider(provider)
+    try:
+        with pytest.raises(ProviderExistsError):
+            dpgm.register_provider(provider)
+    finally:
+        dpgm.unregister_provider("unit-test-duplicate")
+
+
+def test_provider_url_building_with_subdomains_retina_and_extension() -> None:
+    provider = dpgm.TileProvider(
+        name="unit-test-template",
+        url_template="https://{s}.tiles.example.test/{z}/{x}/{y}{r}.{ext}",
+        subdomains=("a", "b", "c"),
+        retina=True,
+        file_extension="webp",
+    )
+
+    assert provider.build_url(x=1, y=2, z=3) == "https://a.tiles.example.test/3/1/2@2x.webp"
+
+
+@pytest.mark.parametrize(
+    "template",
+    [
+        "https://tiles.example.test/{z}/{x}.png",
+        "https://tiles.example.test/{z}/{x}/{y}/{quadkey}.png",
+        "",
+    ],
+)
+def test_invalid_provider_templates_fail(template: str) -> None:
+    with pytest.raises(InvalidProviderError):
+        dpgm.TileProvider(name="bad-template", url_template=template)

tests/test_public_api.py

@@ -0,0 +1,49 @@
+from __future__ import annotations
+
+
+def test_package_exports_required_public_api() -> None:
+    import dpg_map as dpgm
+
+    expected = {
+        "configure",
+        "CacheStats",
+        "TileProvider",
+        "register_provider",
+        "unregister_provider",
+        "get_provider",
+        "list_providers",
+        "map_widget",
+        "set_center",
+        "get_center",
+        "set_zoom",
+        "get_zoom",
+        "set_view",
+        "fit_bounds",
+        "screen_to_latlon",
+        "latlon_to_screen",
+        "add_marker",
+        "add_polyline",
+        "add_trajectory",
+        "update_marker",
+        "update_polyline",
+        "update_trajectory",
+        "set_marker_position",
+        "set_marker_label",
+        "set_polyline_points",
+        "set_overlay_show",
+        "delete_overlay",
+        "add_layer",
+        "show_layer",
+        "hide_layer",
+        "clear_layer",
+        "clear_map",
+        "set_provider",
+        "clear_memory_cache",
+        "clear_disk_cache",
+        "get_cache_stats",
+        "get_map_debug_state",
+    }
+
+    assert set(dpgm.__all__) == expected
+    for name in expected:
+        assert hasattr(dpgm, name)

tests/test_renderer.py

@@ -0,0 +1,176 @@
+from __future__ import annotations
+
+from typing import Any
+
+import dpg_map as dpgm
+from dpg_map.commands import CommandKind, MapCommand
+from dpg_map.providers import TileProvider
+from dpg_map.renderer import MapRenderer, drain_renderer_commands
+from dpg_map.state import DirtyFlags, create_map_state
+from dpg_map.tiles import TileID, TileResult, TileStatus
+
+
+class FakeDpg:
+    def __init__(self) -> None:
+        self.items: set[str | int] = set()
+        self.deleted: list[tuple[str | int, bool]] = []
+        self.drawn: list[tuple[str, str | int]] = []
+
+    def does_item_exist(self, tag: str | int) -> bool:
+        return tag in self.items
+
+    def add_draw_layer(self, *, parent: str | int, tag: str | int) -> None:
+        _ = parent
+        self.items.add(tag)
+
+    def delete_item(self, tag: str | int, *, children_only: bool = False) -> None:
+        self.deleted.append((tag, children_only))
+
+    def draw_rectangle(self, *args: Any, parent: str | int, **kwargs: Any) -> None:
+        _ = (args, kwargs)
+        self.drawn.append(("rectangle", parent))
+
+    def draw_image(self, *args: Any, parent: str | int, **kwargs: Any) -> None:
+        _ = (args, kwargs)
+        self.drawn.append(("image", parent))
+
+    def draw_text(self, *args: Any, parent: str | int, **kwargs: Any) -> None:
+        _ = (args, kwargs)
+        self.drawn.append(("text", parent))
+
+    def draw_circle(self, *args: Any, parent: str | int, **kwargs: Any) -> None:
+        _ = (args, kwargs)
+        self.drawn.append(("circle", parent))
+
+    def draw_polyline(self, *args: Any, parent: str | int, **kwargs: Any) -> None:
+        _ = (args, kwargs)
+        self.drawn.append(("polyline", parent))
+
+
+def test_renderer_command_drain_preserves_structural_order_and_coalesces() -> None:
+    state = create_map_state(tag="renderer-drain")
+    state.dirty = DirtyFlags.NONE
+
+    state.command_queue.put(MapCommand(CommandKind.ADD_OVERLAY, state.tag, {"tag": "a"}))
+    state.command_queue.put(MapCommand(CommandKind.SET_VIEW, state.tag, {"zoom": 3}))
+    state.command_queue.put(MapCommand(CommandKind.SET_VIEW, state.tag, {"zoom": 4}))
+    state.command_queue.put(MapCommand(CommandKind.UPDATE_OVERLAY, state.tag, {"tag": "a", "v": 1}))
+    state.command_queue.put(MapCommand(CommandKind.UPDATE_OVERLAY, state.tag, {"tag": "a", "v": 2}))
+    state.command_queue.put(MapCommand(CommandKind.DELETE_OVERLAY, state.tag, {"tag": "a"}))
+
+    commands = drain_renderer_commands(state)
+
+    assert [command.kind for command in commands] == [
+        CommandKind.ADD_OVERLAY,
+        CommandKind.SET_VIEW,
+        CommandKind.UPDATE_OVERLAY,
+        CommandKind.DELETE_OVERLAY,
+    ]
+    assert commands[1].payload == {"zoom": 4}
+    assert commands[2].payload == {"tag": "a", "v": 2}
+    assert state.dirty & DirtyFlags.VIEW
+    assert state.dirty & DirtyFlags.OVERLAYS
+
+
+def test_overlay_draw_clears_only_overlay_layer() -> None:
+    state = create_map_state(tag="overlay-draw", center=(47.0, 2.0), zoom=8)
+    dpgm.add_marker(
+        "vehicle",
+        lat=47.0,
+        lon=2.0,
+        show_label=True,
+        label="Vehicle",
+        map_tag="overlay-draw",
+    )
+    fake = FakeDpg()
+    fake.items.add(state.drawlist_tag)
+    renderer = MapRenderer(state, fake)
+
+    renderer._draw_tile_layer(
+        visible_tiles=[], width=400, height=300, attribution="Tiles", tile_size=256
+    )
+    fake.deleted.clear()
+    with state.lock:
+        overlays = tuple(state.overlays.values())
+        layers = {name: (layer.show, layer.z_index) for name, layer in state.layers.items()}
+
+    renderer._draw_overlay_layer(
+        overlays=overlays,
+        layers=layers,
+        center=state.center,
+        zoom=state.zoom,
+        width=400,
+        height=300,
+        tile_size=256,
+    )
+
+    assert fake.deleted == [("overlay-draw##layer-overlays", True)]
+    assert ("circle", "overlay-draw##layer-overlays") in fake.drawn
+    assert ("text", "overlay-draw##layer-overlays") in fake.drawn
+
+
+def test_overlay_update_drain_sets_only_overlay_dirty() -> None:
+    state = create_map_state(tag="overlay-dirty")
+    state.dirty = DirtyFlags.NONE
+    state.command_queue.put(MapCommand(CommandKind.UPDATE_OVERLAY, state.tag, {"tag": "a"}))
+
+    drain_renderer_commands(state)
+
+    assert state.dirty == DirtyFlags.OVERLAYS
+
+
+def test_provider_switch_keeps_overlays_and_invalidates_tiles() -> None:
+    provider = TileProvider(
+        name="renderer-switch-provider",
+        url_template="https://tiles.example.test/{z}/{x}/{y}.png",
+        min_zoom=3,
+        max_zoom=4,
+        attribution="Example",
+    )
+    dpgm.register_provider(provider)
+    try:
+        state = create_map_state(tag="provider-switch", center=(47.0, 2.0), zoom=8)
+        dpgm.add_marker("vehicle", lat=47.0, lon=2.0, map_tag="provider-switch")
+        state.command_queue.drain()
+        state.dirty = DirtyFlags.NONE
+        tile_id = TileID("osm", 3, 1, 2)
+        state.tile_manager._result_queue.put(
+            TileResult(
+                tile_id,
+                generation=state.generation,
+                status=TileStatus.READY,
+                width=1,
+                height=1,
+                pixels=(1.0, 1.0, 1.0, 1.0),
+                source="disk",
+            )
+        )
+        state.tile_manager.drain_results(generation=state.generation, provider_name="osm")
+        state.tile_manager.set_texture_tag(tile_id, "old-texture")
+
+        dpgm.set_provider("renderer-switch-provider", map_tag="provider-switch")
+        drain_renderer_commands(state)
+
+        assert "vehicle" in state.overlays
+        assert state.center == (47.0, 2.0)
+        assert state.zoom == 4
+        assert state.generation == 1
+        assert state.provider.name == "renderer-switch-provider"
+        assert state.dirty & DirtyFlags.PROVIDER
+        assert state.dirty & DirtyFlags.TILES
+        assert state.dirty & DirtyFlags.OVERLAYS
+        assert state.tile_manager.get_ready_tile(tile_id) is None
+        assert state.tile_manager.take_texture_deletions() == ["old-texture"]
+    finally:
+        dpgm.unregister_provider("renderer-switch-provider")
+
+
+def test_map_scoped_clear_disk_cache_command_keeps_dearpygui_out_of_caller_thread() -> None:
+    state = create_map_state(tag="clear-disk-command")
+    state.dirty = DirtyFlags.NONE
+
+    dpgm.clear_disk_cache(map_tag="clear-disk-command")
+
+    commands = state.command_queue.drain()
+    assert [command.kind for command in commands] == [CommandKind.CLEAR_DISK_CACHE]
+    assert state.dirty == DirtyFlags.TILES

tests/test_sizing.py

@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+from dpg_map.sizing import SizeMeasurement, apply_size_measurement, effective_draw_size
+from dpg_map.state import DirtyFlags, create_map_state
+
+
+def test_size_measurement_tracks_last_nonzero_size() -> None:
+    state = create_map_state(tag="size-last-nonzero")
+
+    first = apply_size_measurement(state, SizeMeasurement(width=640, height=360, visible=True))
+    hidden = apply_size_measurement(state, SizeMeasurement(width=0, height=0, visible=False))
+
+    assert first.changed is True
+    assert state.measured_width == 0
+    assert state.measured_height == 0
+    assert state.last_nonzero_width == 640
+    assert state.last_nonzero_height == 360
+    assert hidden.became_hidden is True
+    assert effective_draw_size(state) == (640, 360)
+
+
+def test_zero_size_does_not_permanently_collapse_map() -> None:
+    state = create_map_state(tag="size-reappears")
+
+    apply_size_measurement(state, SizeMeasurement(width=500, height=300, visible=True))
+    apply_size_measurement(state, SizeMeasurement(width=0, height=0, visible=False))
+    update = apply_size_measurement(state, SizeMeasurement(width=700, height=450, visible=True))
+
+    assert update.became_visible is True
+    assert update.effective_width == 700
+    assert update.effective_height == 450
+    assert state.last_nonzero_width == 700
+    assert state.last_nonzero_height == 450
+
+
+def test_resize_marks_size_dirty() -> None:
+    state = create_map_state(tag="size-dirty")
+    state.dirty = DirtyFlags.NONE
+
+    apply_size_measurement(state, SizeMeasurement(width=320, height=240, visible=True))
+
+    assert state.dirty & DirtyFlags.SIZE
+    assert state.dirty & DirtyFlags.TILES
+    assert state.dirty & DirtyFlags.OVERLAYS

tests/test_tiles.py

@@ -0,0 +1,87 @@
+from __future__ import annotations
+
+from io import BytesIO
+
+from PIL import Image
+
+from dpg_map.providers import OSM
+from dpg_map.tiles import (
+    TileID,
+    TileManager,
+    TileResult,
+    TileStatus,
+    calculate_visible_tiles,
+    decode_tile_image,
+)
+
+
+def test_visible_tile_calculation_uses_provider_namespace() -> None:
+    tiles = calculate_visible_tiles(
+        center=(0.0, 0.0),
+        zoom=2,
+        width=256,
+        height=256,
+        provider=OSM,
+        margin=0,
+    )
+
+    assert tiles
+    assert {tile.tile_id.provider_name for tile in tiles} == {"osm"}
+    assert all(0 <= tile.tile_id.x <= 3 for tile in tiles)
+    assert all(0 <= tile.tile_id.y <= 3 for tile in tiles)
+
+
+def test_tile_manager_ignores_stale_generation_results() -> None:
+    manager = TileManager()
+    stale = TileResult(
+        TileID("osm", 1, 0, 0),
+        generation=1,
+        status=TileStatus.READY,
+        width=1,
+        height=1,
+        pixels=(1.0, 1.0, 1.0, 1.0),
+        source="disk",
+    )
+    manager._result_queue.put(stale)
+
+    accepted = manager.drain_results(generation=2, provider_name="osm")
+
+    assert accepted == []
+    assert manager.snapshot().stale_results == 1
+
+
+def test_memory_eviction_protects_visible_tiles() -> None:
+    manager = TileManager(memory_cache_max_tiles=1)
+    protected = TileID("osm", 1, 0, 0)
+    evictable = TileID("osm", 1, 0, 1)
+    with manager._lock:
+        manager._visible_tile_ids = {protected}
+
+    for tile_id in (protected, evictable):
+        manager._result_queue.put(
+            TileResult(
+                tile_id,
+                generation=1,
+                status=TileStatus.READY,
+                width=1,
+                height=1,
+                pixels=(1.0, 1.0, 1.0, 1.0),
+                source="disk",
+            )
+        )
+
+    manager.drain_results(generation=1, provider_name="osm")
+
+    assert manager.get_ready_tile(protected) is not None
+    assert manager.get_ready_tile(evictable) is None
+
+
+def test_decode_png_tile_image() -> None:
+    image = Image.new("RGBA", (1, 1), (255, 0, 128, 255))
+    buffer = BytesIO()
+    image.save(buffer, format="PNG")
+
+    width, height, pixels = decode_tile_image(buffer.getvalue())
+
+    assert (width, height) == (1, 1)
+    assert pixels == (1.0, 0.0, 128 / 255, 1.0)

uv.lock

@@ -74,7 +74,7 @@ wheels = [
 
 [[package]]
 name = "dpg-map"
-version = "0.1.0"
+version = "0.3.0b1"
 source = { editable = "." }
 dependencies = [
     { name = "dearpygui" },