fix(cursor): normalize native cursor density in scaled views

flutter/test/cursor_dpi_policy_test.dart

@@ -0,0 +1,180 @@
+import 'dart:io';
+import 'dart:ui' as ui;
+
+import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_hbb/consts.dart';
+import 'package:flutter_hbb/desktop/pages/remote_page.dart';
+import 'package:flutter_hbb/models/input_model.dart';
+import 'package:flutter_hbb/models/model.dart';
+import 'package:flutter_hbb/native/custom_cursor.dart' show deleteCustomCursor;
+import 'package:flutter_test/flutter_test.dart';
+import 'package:get/get.dart';
+import 'package:image/image.dart' as img;
+import 'package:provider/provider.dart';
+
+const _viewport = Size(200, 160);
+
+class _Image extends ChangeNotifier implements ImageModel {
+  @override
+  bool get useTextureRender => false;
+  @override
+  ui.Image? get image => null;
+  @override
+  dynamic noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
+}
+
+class _Canvas extends ChangeNotifier implements CanvasModel {
+  _Canvas(this.devicePixelRatio, {required this.style, required this.scale});
+
+  final String style;
+
+  @override
+  final double devicePixelRatio;
+  @override
+  final imageOverflow = false.obs;
+  @override
+  late final viewStyle = ViewStyle(
+    style: style,
+    width: _viewport.width,
+    height: _viewport.height,
+    displayWidth: 400,
+    displayHeight: 320,
+  );
+  @override
+  bool get cursorEmbedded => false;
+  @override
+  Size get size => _viewport;
+  @override
+  final double scale;
+  @override
+  double get x => 0;
+  @override
+  double get y => 0;
+  @override
+  dynamic noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
+}
+
+class _Cursor extends ChangeNotifier implements CursorModel {
+  _Cursor(this.cache, this._ffi);
+
+  final FFI _ffi;
+  @override
+  WeakReference<FFI> get parent => WeakReference(_ffi);
+
+  @override
+  CursorData cache;
+  @override
+  ui.Image? get image => null;
+  @override
+  double get hotx => cache.hotxOrigin;
+  @override
+  double get hoty => cache.hotyOrigin;
+  @override
+  final Set<String> cachedKeys = {};
+  @override
+  void addKey(String key) => cachedKeys.add(key);
+  @override
+  dynamic noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
+}
+
+class _Input extends Fake implements InputModel {
+  @override
+  final relativeMouseMode = false.obs;
+}
+
+class _Peer extends Fake implements FfiModel {
+  @override
+  final pi = PeerInfo();
+  @override
+  bool get isPeerLinux => false;
+}
+
+class _FFI extends Fake implements FFI {
+  _FFI(this.canvasModel);
+
+  @override
+  final CanvasModel canvasModel;
+  @override
+  final inputModel = _Input();
+  @override
+  final ffiModel = _Peer();
+}
+
+Future<CursorData> _data(int density, String id) async {
+  final image = await createTestImage(width: 9 * density, height: 18 * density);
+  return CursorData(
+    peerId: 'dpi-policy',
+    id: id,
+    image: img.Image(width: image.width, height: image.height, numChannels: 4),
+    nativeImage: image,
+    scale: 1,
+    data: null,
+    hotxOrigin: 4.0 * density,
+    hotyOrigin: 9.0 * density,
+    width: image.width,
+    height: image.height,
+    pixelRatio: density.toDouble(),
+  );
+}
+
+void main() {
+  for (final (style, zoom, density, viewScale, expectedScale) in [
+    (kRemoteViewStyleAdaptive, false, 1, 0.25, Platform.isWindows ? 2.0 : 1.0),
+    (kRemoteViewStyleAdaptive, false, 2, 0.25, Platform.isWindows ? 1.0 : 0.5),
+    (kRemoteViewStyleCustom, false, 2, 0.25, Platform.isWindows ? 1.0 : 0.5),
+    (kRemoteViewStyleAdaptive, true, 2, 0.25, 1 / 3),
+    (kRemoteViewStyleCustom, true, 2, 0.25, 1 / 3),
+    (kRemoteViewStyleOriginal, false, 2, 0.5, Platform.isWindows ? 1.0 : 2 / 3),
+  ]) {
+    testWidgets(
+        '$style zoom=$zoom peerDPR=$density keeps cursor units',
+        (tester) => tester.runAsync(() async {
+              tester.view.devicePixelRatio = 2;
+              addTearDown(tester.view.resetDevicePixelRatio);
+              final channel = Platform.isWindows
+                  ? SystemChannels.mouseCursor
+                  : const MethodChannel('flutter_custom_cursor');
+              tester.binding.defaultBinaryMessenger.setMockMethodCallHandler(
+                  channel,
+                  (call) async => call.method.startsWith('createCustomCursor')
+                      ? (call.arguments as Map<dynamic, dynamic>)['name']
+                      : null);
+              final data = await _data(density, '$style-$zoom-$density');
+              // A stale cached DPR must not affect the cursor when the window moves.
+              final canvas = _Canvas(1, style: style, scale: viewScale);
+              final ffi = _FFI(canvas);
+              final cursor = _Cursor(data, ffi);
+              await tester.pumpWidget(MediaQuery(
+                data: const MediaQueryData(devicePixelRatio: 2),
+                child: MultiProvider(
+                    providers: [
+                      ChangeNotifierProvider<ImageModel>(
+                          create: (_) => _Image()),
+                      ChangeNotifierProvider<CanvasModel>.value(value: canvas),
+                      ChangeNotifierProvider<CursorModel>.value(value: cursor),
+                    ],
+                    child: ImagePaint(
+                      ffi: ffi,
+                      id: 'dpi-policy',
+                      zoomCursor: zoom.obs,
+                      cursorOverImage: true.obs,
+                      keyboardEnabled: true.obs,
+                      remoteCursorMoved: false.obs,
+                    )),
+              ));
+              await tester.pumpWidget(const SizedBox.shrink());
+              await Future.wait(cursor.cachedKeys.map((key) async {
+                await deleteCustomCursor(key);
+              }));
+              data.nativeImage.dispose();
+              cursor.dispose();
+              canvas.dispose();
+              tester.binding.defaultBinaryMessenger
+                  .setMockMethodCallHandler(channel, null);
+              expect(data.scale, closeTo(expectedScale, 1e-9));
+              expect(data.hotx, closeTo(4 * density * expectedScale, 1e-9));
+              expect(data.hoty, closeTo(9 * density * expectedScale, 1e-9));
+            }));
+  }
+}

flutter/test/cursor_paint_scale_test.dart

@@ -113,7 +113,7 @@ void main() {
       2.0,
       (9, 18),
       0.1,
-      Platform.isWindows ? 2 / 3 : 4 / 3,
+      Platform.isWindows ? 1 / 3 : 2 / 3,
       true
     ),
   ]) {