Fixed updating of used tilesets after resizing map

When a tileset became unused due to a resize map or offset map
operation, the tileset could stay in the set of "used tilesets" reported
for that map.

This affected the scripting API Map.usedTilesets and caused an
unnecessary warning when trying to remove the affected tileset using the
"Remove Tileset" action.

Closes #3884

NEWS.md

@@ -14,6 +14,7 @@
 * Windows: Fixed the support for WebP images (updated to Qt 6.6.1, #3661)
 * Fixed mouse handling issue when zooming while painting (#3863)
 * Fixed possible crash after a scripted tool disappears while active
+* Fixed updating of used tilesets after resizing map (#3884)
 * TMX format: Embedded images are now also supported on tilesets and image layers
 * AppImage: Updated to Sentry 0.6.7
 

src/libtiled/tilelayer.cpp

@@ -612,6 +612,8 @@ void TileLayer::resize(QSize size, QPoint offset)
 
     mChunks = newLayer->mChunks;
     mBounds = newLayer->mBounds;
+    mUsedTilesets = newLayer->mUsedTilesets;
+    mUsedTilesetsDirty = newLayer->mUsedTilesetsDirty;
     setSize(size);
 }
 
@@ -655,6 +657,8 @@ void TileLayer::offsetTiles(QPoint offset,
 
     mChunks = newLayer->mChunks;
     mBounds = newLayer->mBounds;
+    mUsedTilesets = newLayer->mUsedTilesets;
+    mUsedTilesetsDirty = newLayer->mUsedTilesetsDirty;
 }
 
 void TileLayer::offsetTiles(QPoint offset)