fix(flutter): align painted cursor with the software image origin

flutter/lib/desktop/pages/remote_page.dart

@@ -1425,8 +1425,9 @@ class CursorPaint extends StatelessWidget {
       }
     }
 
-    double cx = c.x;
+    final imageOffset = _softwareImageOffset(c);
-    double cy = c.y;
+    double cx = imageOffset?.dx ?? c.x;
+    double cy = imageOffset?.dy ?? c.y;
     if (c.viewStyle.style == kRemoteViewStyleOriginal &&
         c.scrollStyle == ScrollStyle.scrollbar) {
       final rect = c.parent.target!.ffiModel.rect;
@@ -1467,4 +1468,22 @@ class CursorPaint extends StatelessWidget {
       ),
     );
   }
+
+  Offset? _softwareImageOffset(CanvasModel canvas) {
+    if (canvas.imageOverflow.isTrue &&
+        canvas.scrollStyle != ScrollStyle.scrollauto) {
+      return null;
+    }
+    final ffi = canvas.parent.target!;
+    final peer = ffi.ffiModel;
+    if (ffi.imageModel.useTextureRender || peer.pi.forceTextureRender) {
+      return null;
+    }
+    var scale = canvas.scale;
+    final displays = peer.pi.getCurDisplays();
+    if (peer.isPeerLinux && displays.isNotEmpty) scale /= displays[0].scale;
+    // Match the origin used by _buildScrollAutoNonTextureRender's ImagePainter.
+    return Offset(
+        (canvas.x / scale).toInt() * scale, (canvas.y / scale).toInt() * scale);
+  }
 }

flutter/test/cursor_paint_scale_test.dart

@@ -33,9 +33,33 @@ class _CursorModel extends ChangeNotifier implements CursorModel {
   dynamic noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 }
 
+class _ImageModel extends Fake implements ImageModel {
+  _ImageModel(this.useTextureRender);
+
+  @override
+  final bool useTextureRender;
+}
+
+class _Peer extends Fake implements FfiModel {
+  @override
+  final pi = PeerInfo();
+  @override
+  bool get isPeerLinux => false;
+}
+
+class _FFI extends Fake implements FFI {
+  _FFI(bool useTexture) : imageModel = _ImageModel(useTexture);
+
+  @override
+  final ImageModel imageModel;
+  @override
+  final ffiModel = _Peer();
+}
+
 class _CanvasModel extends ChangeNotifier implements CanvasModel {
-  _CanvasModel(String style, this.scale)
+  _CanvasModel(String style, this.scale, bool useTexture)
-      : viewStyle = ViewStyle(
+      : _ffi = _FFI(useTexture),
+        viewStyle = ViewStyle(
           style: style,
           width: _viewport.width,
           height: _viewport.height,
@@ -43,6 +67,11 @@ class _CanvasModel extends ChangeNotifier implements CanvasModel {
           displayHeight: _viewport.height.toInt(),
         );
 
+  final FFI _ffi;
+  @override
+  WeakReference<FFI> get parent => WeakReference(_ffi);
+  @override
+  final imageOverflow = false.obs;
   @override
   final ViewStyle viewStyle;
   @override
@@ -72,19 +101,20 @@ class _Canvas extends Fake implements Canvas {
 }
 
 void main() {
-  for (final (style, zoom, dpr, source, canvasScale, scale) in [
+  for (final (style, zoom, dpr, source, canvasScale, scale, texture) in [
-    (kRemoteViewStyleAdaptive, false, 2.0, (48, 64), 0.375, 0.375),
+    (kRemoteViewStyleAdaptive, false, 2.0, (48, 64), 0.375, 0.375, true),
-    (kRemoteViewStyleAdaptive, false, 3.0, (48, 64), 0.25, 0.25),
+    (kRemoteViewStyleAdaptive, false, 3.0, (48, 64), 0.25, 0.25, true),
-    (kRemoteViewStyleAdaptive, true, 3.0, (48, 64), 0.375, 0.375),
+    (kRemoteViewStyleAdaptive, true, 3.0, (48, 64), 0.375, 0.375, true),
-    (kRemoteViewStyleOriginal, false, 2.0, (48, 64), 0.5, 0.5),
+    (kRemoteViewStyleOriginal, false, 2.0, (48, 64), 0.5, 0.5, true),
-    (kRemoteViewStyleOriginal, true, 2.0, (48, 64), 0.5, 0.5),
+    (kRemoteViewStyleOriginal, true, 2.0, (48, 64), 0.5, 0.5, true),
     (
       kRemoteViewStyleAdaptive,
       false,
       2.0,
       (9, 18),
       0.1,
-      Platform.isWindows ? 2 / 3 : 4 / 3
+      Platform.isWindows ? 2 / 3 : 4 / 3,
+      true
     ),
     (
       kRemoteViewStyleAdaptive,
@@ -92,11 +122,22 @@ void main() {
       2.0,
       (9, 18),
       0.1,
-      Platform.isWindows ? 2 / 3 : 4 / 3
+      Platform.isWindows ? 2 / 3 : 4 / 3,
+      true
+    ),
+    (kRemoteViewStyleAdaptive, false, 2.25, (48, 48), 0.375, 0.375, false),
+    (
+      kRemoteViewStyleAdaptive,
+      true,
+      2.0,
+      (9, 18),
+      0.1,
+      Platform.isWindows ? 2 / 3 : 4 / 3,
+      false
     ),
   ]) {
     testWidgets(
-        '$style zoom=$zoom dpr=$dpr source=$source keeps remote geometry',
+        '$style zoom=$zoom dpr=$dpr source=$source texture=$texture keeps remote geometry',
         (tester) async {
       final image = (await tester.runAsync(
           () => createTestImage(width: source.$1, height: source.$2)))!;
@@ -108,7 +149,7 @@ void main() {
             ChangeNotifierProvider<CursorModel>(
                 create: (_) => _CursorModel(image)),
             ChangeNotifierProvider<CanvasModel>(
-                create: (_) => _CanvasModel(style, canvasScale)),
+                create: (_) => _CanvasModel(style, canvasScale, texture)),
           ],
           child: CursorPaint(id: 'cursor-test', zoomCursor: zoom.obs),
         ),
@@ -119,12 +160,22 @@ void main() {
 
       expect(painter.image, same(image));
       expect(painter.scale, scale);
-      expect((Offset(painter.x, painter.y) + _hotspot) * scale,
+      var imageOrigin = _canvasOffset;
-          _remotePosition * canvasScale + _canvasOffset);
+      if (!texture) {
+        final background = _Canvas();
+        ImagePainter(
+          image: image,
+          x: _canvasOffset.dx / canvasScale,
+          y: _canvasOffset.dy / canvasScale,
+          scale: canvasScale,
+        ).paint(background, _viewport);
+        imageOrigin = background.position!;
+      }
+      final target = _remotePosition * canvasScale + imageOrigin;
+      expect((Offset(painter.x, painter.y) + _hotspot) * scale, target);
       final canvas = _Canvas();
       painter.paint(canvas, _viewport);
       final position = canvas.position! + _hotspot * canvas.factor;
-      final target = _remotePosition * canvasScale + _canvasOffset;
       expect(position.dx, closeTo(target.dx, 1e-9));
       expect(position.dy, closeTo(target.dy, 1e-9));
     });