feat: initial custom cursor and cache support

Author: Kingtous

shell/platform/windows/cursor_handler.cc

@@ -11,6 +11,7 @@
 static constexpr char kChannelName[] = "flutter/mousecursor";
 
 static constexpr char kActivateSystemCursorMethod[] = "activateSystemCursor";
+static constexpr char kSetSystemCursorMethod[] = "setSystemCursor";
 
 static constexpr char kKindKey[] = "kind";
 
@@ -45,6 +46,31 @@ void CursorHandler::HandleMethodCall(
     const auto& kind = std::get<std::string>(kind_iter->second);
     delegate_->UpdateFlutterCursor(kind);
     result->Success();
+  } else if (method.compare(kSetSystemCursorMethod) == 0) {
+    const auto& map = std::get<EncodableMap>(*method_call.arguments());
+    auto buffer = std::get<std::vector<uint8_t>>(
+        map.at(flutter::EncodableValue("buffer")));
+    auto width = std::get<int>(map.at(flutter::EncodableValue("width")));
+    auto height = std::get<int>(map.at(flutter::EncodableValue("height")));
+    auto hotx = std::get<double>(map.at(flutter::EncodableValue("hotx")));
+    auto hoty = std::get<double>(map.at(flutter::EncodableValue("hoty")));
+    HCURSOR cursor = nullptr;
+    // Flutter returns rawRgba, which has 8bits*4channels
+    auto bitmap = CreateBitmap(width, height, 1, 32, &buffer[0]);
+    if (bitmap == nullptr) {
+      result->Error("Argument error", "Invalid rawRgba bitmap from flutter");
+      return;
+    }
+    ICONINFO icon_info;
+    icon_info.fIcon = 0;
+    icon_info.xHotspot = hotx;
+    icon_info.yHotspot = hoty;
+    icon_info.hbmMask = bitmap;
+    icon_info.hbmColor = bitmap;
+    cursor = CreateIconIndirect(&icon_info);
+    DeleteObject(bitmap);
+    delegate_->SetFlutterCursor(cursor);
+    result->Success();
   } else {
     result->NotImplemented();
   }

shell/platform/windows/flutter_window.cc

@@ -105,6 +105,10 @@ void FlutterWindow::UpdateFlutterCursor(const std::string& cursor_name) {
   current_cursor_ = GetCursorByName(cursor_name);
 }
 
+void FlutterWindow::SetFlutterCursor(HCURSOR cursor) {
+  current_cursor_ = cursor;
+}
+
 void FlutterWindow::OnWindowResized() {
   // Blocking the raster thread until DWM flushes alleviates glitches where
   // previous size surface is stretched over current size view.

shell/platform/windows/flutter_window.h

@@ -131,6 +131,9 @@ class FlutterWindow : public Window, public WindowBindingHandler {
   // |FlutterWindowBindingHandler|
   void UpdateFlutterCursor(const std::string& cursor_name) override;
 
+  // |FlutterWindowBindingHandler|
+  void SetFlutterCursor(HCURSOR cursor) override;
+
   // |FlutterWindowBindingHandler|
   void OnWindowResized() override;
 

shell/platform/windows/testing/mock_window_binding_handler.h

@@ -31,6 +31,7 @@ class MockWindowBindingHandler : public WindowBindingHandler {
   MOCK_METHOD0(OnWindowResized, void());
   MOCK_METHOD0(GetPhysicalWindowBounds, PhysicalWindowBounds());
   MOCK_METHOD1(UpdateFlutterCursor, void(const std::string& cursor_name));
+  MOCK_METHOD1(SetFlutterCursor, void(HCURSOR cursor_name));
   MOCK_METHOD1(OnCursorRectUpdated, void(const Rect& rect));
   MOCK_METHOD0(OnResetImeComposing, void());
   MOCK_METHOD3(OnBitmapSurfaceUpdated,

shell/platform/windows/window_binding_handler.h

@@ -71,6 +71,9 @@ class WindowBindingHandler {
   // content. See mouse_cursor.dart for the values and meanings of cursor_name.
   virtual void UpdateFlutterCursor(const std::string& cursor_name) = 0;
 
+  // Sets the cursor from path
+  virtual void SetFlutterCursor(HCURSOR cursor) = 0;
+
   // Invoked when the cursor/composing rect has been updated in the framework.
   virtual void OnCursorRectUpdated(const Rect& rect) = 0;