Fix for Crash in ScintillaWinUI::DrawBit with too large drawingBounds parameter

WinUIEditor/EditorBaseControl.cpp

@@ -377,6 +377,9 @@ namespace winrt::WinUIEditor::implementation
 			const ImageBrush brush{};
 			brush.ImageSource(virtualSurfaceImageSource);
 			imageTarget.Background(brush);
+
+			_wrapper->SetContainer(imageTarget);
+			UpdateVisibleArea();
 		}
 
 #ifndef WINUI3
@@ -539,6 +542,8 @@ namespace winrt::WinUIEditor::implementation
 	{
 		if (_vsisNative)
 		{
+			UpdateVisibleArea();
+
 			auto width{ ConvertFromDipToPixelUnit(args.NewSize().Width, _dpiScale) };
 			auto height{ ConvertFromDipToPixelUnit(args.NewSize().Height, _dpiScale) };
 			_wrapper->Width(width);
@@ -552,6 +557,7 @@ namespace winrt::WinUIEditor::implementation
 	{
 		auto properties{ e.GetCurrentPoint(sender.as<UIElement>()).Properties() };
 		_scintilla->PointerWheelChanged(properties.MouseWheelDelta(), properties.IsHorizontalMouseWheel(), e.KeyModifiers());
+		UpdateVisibleArea();
 	}
 
 	void EditorBaseControl::ImageTarget_DragEnter(IInspectable const &sender, DragEventArgs const &e)
@@ -672,4 +678,35 @@ namespace winrt::WinUIEditor::implementation
 		_wrapper->TrimDxgiDevice();
 	}
 #endif
+
+	void EditorBaseControl::UpdateVisibleArea()
+	{
+		auto container = _wrapper->GetContainer();
+
+		// Get the XamlRoot associated with the UIElement
+		auto xamlRoot = XamlRoot();
+		if (!xamlRoot)
+		{
+			throw std::runtime_error("XamlRoot is null. Ensure the element is attached to the visual tree.");
+		}
+
+		// Get the bounds of the UIElement relative to the XamlRoot
+		auto elementTransform = TransformToVisual(xamlRoot.Content());
+		Rect elementBounds = elementTransform.TransformBounds(
+			Rect{ 0, 0, (float)ActualWidth(), (float)ActualHeight() });
+
+		// Get the bounds of the XamlRoot
+		auto xamlRootSize = xamlRoot.Content().ActualSize();
+		Rect xamlRootBounds{ 0, 0, xamlRootSize.x,  xamlRootSize.y };
+
+		// Calculate the intersection of the two rectangles
+		auto intersection = RectHelper::Intersect(elementBounds, xamlRootBounds);
+
+		_scintilla->SetVisibleArea(
+			ConvertFromDipToPixelUnit(intersection.X, _dpiScale),
+			ConvertFromDipToPixelUnit(intersection.Y, _dpiScale),
+			ConvertFromDipToPixelUnit(intersection.Width, _dpiScale),
+			ConvertFromDipToPixelUnit(intersection.Height, _dpiScale)
+		);
+	}
 }

WinUIEditor/EditorBaseControl.h

@@ -113,6 +113,7 @@ namespace winrt::WinUIEditor::implementation
 		Windows::UI::Xaml::Application::Suspending_revoker _suspendingRevoker{};
 		void Application_Suspending(Windows::Foundation::IInspectable const &sender, Windows::ApplicationModel::SuspendingEventArgs const &args);
 #endif
+		void UpdateVisibleArea();
 	};
 }
 

WinUIEditor/MainWrapper.cpp

@@ -167,4 +167,14 @@ namespace WinUIEditor
 	void MainWrapper::SetPositionRelative(Scintilla::Internal::PRectangle rc, Wrapper const &wrapper)
 	{
 	}
+
+	void MainWrapper::SetContainer(winrt::DUX::FrameworkElement const& container)
+	{
+		_container = container;
+	}
+
+	winrt::DUX::FrameworkElement MainWrapper::GetContainer()
+	{
+		return _container;
+	}
 }

WinUIEditor/MainWrapper.h

@@ -42,11 +42,16 @@ namespace WinUIEditor
 		void Destroy() override;
 		void SetPositionRelative(Scintilla::Internal::PRectangle rc, Wrapper const &wrapper) override;
 
+		void SetContainer(winrt::DUX::FrameworkElement const& container);
+		winrt::DUX::FrameworkElement MainWrapper::GetContainer();
+
 	private:
 		winrt::DUX::Input::Pointer _lastPointer{ nullptr };
 		winrt::DUX::UIElement _mouseCaptureElement{ nullptr };
 		winrt::DUX::Controls::Primitives::ScrollBar _horizontalScrollBar{ nullptr };
 		winrt::DUX::Controls::Primitives::ScrollBar _verticalScrollBar{ nullptr };
 		bool _captured{ false };
+
+		winrt::DUX::FrameworkElement _container{ nullptr };
 	};
 }

scintilla/winui/ScintillaWin.cxx

@@ -2614,7 +2614,7 @@ namespace Scintilla::Internal {
 			paintState = PaintState::painting;
 			paintingAllText = true;
 			// Todo: This is in contradiction with the above paragraph about drawing size. But invalidation results in flickering
-			DrawBit(RECT{ 0, 0, _mainWrapper->Width(), _mainWrapper->Height() });
+			DrawBit(visibleArea); // draw ony visible area, _mainWrapper->Width() & Height() can be too big
 		}
 
 		paintState = PaintState::notPainting;
@@ -2651,7 +2651,7 @@ namespace Scintilla::Internal {
 			_mainWrapper->CreateGraphicsDevices();
 			InvalidateStyleRedraw(); // just Redraw() does not work
 		}
-		else
+		else if (beginDrawHR == S_OK)
 		{
 			const auto &d2dDeviceContext{ _mainWrapper->D2dDeviceContext() };
 
@@ -3202,4 +3202,9 @@ namespace Scintilla::Internal {
 
 		sisNativeWithD2D->EndDraw();
 	}
+
+	void ScintillaWinUI::SetVisibleArea(LONG x, LONG y, LONG width, LONG height)
+	{
+		visibleArea = RECT{ x, y, width, height };
+	}
 }

scintilla/winui/ScintillaWin.h

@@ -108,6 +108,7 @@ namespace Scintilla::Internal {
 		static sptr_t DirectStatusFunction(sptr_t ptr, UINT iMessage, uptr_t wParam, sptr_t lParam, int *pStatus);
 		sptr_t WndProc(Message iMessage, uptr_t wParam, sptr_t lParam) override;
 
+		void SetVisibleArea(LONG x, LONG y, LONG width, LONG height);
 	private:
 		bool _tsfCore;
 
@@ -281,6 +282,8 @@ namespace Scintilla::Internal {
 		winrt::fire_and_forget DoDragAsync();
 		int CalculateNotifyMessageUtf16Length(Scintilla::Notification const &code, Scintilla::ModificationFlags const &modFlags, bool notifyTsf, const char *text, Scintilla::Position mbLength);
 		sptr_t OnSetDocPointer(uptr_t wParam, sptr_t lParam);
+
+		RECT visibleArea;
 	};
 
 	class CallTipCallback : public ::winrt::implements<CallTipCallback, ::IVirtualSurfaceUpdatesCallbackNative>