fix(raster): render restored rasters and keep globe view on the WASM engine

Two follow-ups to making cog-tiler-wasm the default engine.

Opening a saved project in a running app left the raster invisible. The
engine deferred its first layer-add until the style could accept it, but
waited on MapLibre's `load` event, which fires exactly once per map -- so
an engine whose first apply landed after the map had loaded (while the
project's style swap was in flight) attached a handler that never fired
and never added its layers at all. The layer sat in the panel with
correct bounds, bands, and symbology, rendering nothing. Fixed upstream
in maplibre-gl-raster v0.14.1 (opengeos/maplibre-gl-raster#57), which
waits on `styledata` instead; this bumps to it.

Adding a raster no longer drops the map out of globe view. The mercator
switch exists because deck.gl's COG tile traversal cannot draw on the
globe -- which is true of the deck.gl engine only. The WASM and TiTiler
engines render through a native MapLibre raster layer that draws on the
globe like any other raster source, so the switch is now gated on the
engine. It still fires on `rasterchange`, which is what setEngine emits,
so switching back to the GPU engine forces mercator for the rasters
already on the map rather than only the next one added.

Author: giswqs

apps/geolibre-desktop/package.json

@@ -76,7 +76,7 @@
     "maplibre-gl-nasa-earthdata": "^0.1.4",
     "maplibre-gl-national-map": "^0.1.1",
     "maplibre-gl-planetary-computer": "^0.4.0",
-    "maplibre-gl-raster": "^0.14.0",
+    "maplibre-gl-raster": "^0.14.1",
     "maplibre-gl-splat": "^0.2.8",
     "maplibre-gl-streetview": "^0.7.0",
     "maplibre-gl-swipe": "^0.11.0",

package-lock.json

@@ -52,7 +52,7 @@
     "maplibre-gl-national-map": "^0.1.1",
     "maplibre-gl-overture-maps": "^0.3.1",
     "maplibre-gl-planetary-computer": "^0.4.0",
-    "maplibre-gl-raster": "^0.14.0",
+    "maplibre-gl-raster": "^0.14.1",
     "maplibre-gl-splat": "^0.2.8",
     "maplibre-gl-streetview": "^0.7.0",
     "maplibre-gl-swipe": "^0.11.0",

packages/plugins/package.json

@@ -16,6 +16,7 @@ import {
 import {
   isRasterControlStoreLayer,
   rememberLocalRasterPath,
+  rendersNativeMapLibreLayer,
   resetRasterStoreSyncSuspension,
   runWithRasterStoreSyncSuspended,
   savedRasterState,
@@ -729,7 +730,20 @@ function createRasterControl(RasterControlClass: RasterControlConstructor): Rast
   // deck.gl's COG tile traversal does not support MapLibre's globe view
   // ("TODO: implement getBoundingVolume in Globe view"), so adding a raster
   // switches the map to mercator, like the other deck.gl-backed plugins.
-  control.on("rasteradd", () => ensureMercatorProjection(control.getMap()));
+  // Only the deck.gl engine needs this: the WASM and TiTiler engines render
+  // through a native MapLibre raster layer, which draws on the globe just like
+  // any other raster source, so forcing mercator there would drop the user out
+  // of globe view for no reason.
+  // Also on rasterchange, which is what setEngine emits: switching the panel
+  // from the WASM engine back to the deck.gl one has to force mercator for the
+  // rasters already on the map, not just for the next one added.
+  for (const event of ["rasteradd", "rasterchange"] as const) {
+    control.on(event, () => {
+      if (rendersNativeMapLibreLayer(control.getEngine())) return;
+      if (control.getRasters().length === 0) return;
+      ensureMercatorProjection(control.getMap());
+    });
+  }
   for (const event of ["rasteradd", "rasterchange", "rasterremove"] as const) {
     control.on(event, () => syncRasterLayersToStoreForRuntime(control));
   }

packages/plugins/src/plugins/maplibre-raster.ts

@@ -66,7 +66,7 @@ export type RasterSyncOptions = {
  * where the deck.gl overlay is a separate stacked canvas with no style layer at
  * all (issue #1463).
  */
-function rendersNativeMapLibreLayer(engine: RenderEngine): boolean {
+export function rendersNativeMapLibreLayer(engine: RenderEngine): boolean {
   return engine === "cog-tiler-wasm" || engine === "titiler";
 }
 

packages/plugins/src/plugins/raster-layer-sync.ts

@@ -8,6 +8,7 @@ import {
   localRasterPath,
   rememberLocalRasterPath,
   removeRasterStoreLayers,
+  rendersNativeMapLibreLayer,
   runWithRasterStoreSyncSuspended,
   savedRasterState,
   syncRasterLayersToStore,
@@ -78,6 +79,19 @@ function otherStoreLayer(id = "unrelated"): GeoLibreLayer {
   };
 }
 
+// The projection rule in maplibre-raster.ts keys off this: only the deck.gl
+// engine cannot draw on the globe, so only it forces the map to mercator.
+describe("rendersNativeMapLibreLayer", () => {
+  it("is true for the engines backed by a real MapLibre raster layer", () => {
+    assert.equal(rendersNativeMapLibreLayer("cog-tiler-wasm"), true);
+    assert.equal(rendersNativeMapLibreLayer("titiler"), true);
+  });
+
+  it("is false for the deck.gl engine", () => {
+    assert.equal(rendersNativeMapLibreLayer("maplibre-gl-raster"), false);
+  });
+});
+
 describe("createRasterStoreLayer", () => {
   it("mirrors a URL raster as an external custom cog layer", () => {
     const layer = createRasterStoreLayer(