Bug [#2344]. Avoid blurry display with DirectWrite in GDI scaling mode.

https://sourceforge.net/p/scintilla/code/merge-requests/28/

1 files changed, 27 insertions, 10 deletions

diff --git a/win32/ScintillaWin.cxx b/win32/ScintillaWin.cxx
index d3c1b87a5..efbe1f000 100644
--- a/win32/ScintillaWin.cxx
+++ b/win32/ScintillaWin.cxx
@@ -324,6 +324,8 @@ class ScintillaWin :
 	static ATOM scintillaClassAtom;
 	static ATOM callClassAtom;
 
+	int deviceScaleFactor = 1;
+
 #if defined(USE_D2D)
 	ID2D1RenderTarget *pRenderTarget;
 	bool renderTargetValid;
@@ -626,11 +628,23 @@ bool ScintillaWin::UpdateRenderingParams(bool force) noexcept {
 	}
 
 	hCurrentMonitor = monitor;
+	deviceScaleFactor = Internal::GetDeviceScaleFactorWhenGdiScalingActive(hRootWnd);
 	renderingParams->defaultRenderingParams.reset(monitorRenderingParams);
 	renderingParams->customRenderingParams.reset(customClearTypeRenderingParams);
 	return true;
 }
 
+namespace {
+
+D2D1_SIZE_U GetSizeUFromRect(const RECT &rc, const int scaleFactor) noexcept {
+	const long width = rc.right - rc.left;
+	const long height = rc.bottom - rc.top;
+	const UINT32 scaledWidth = width * scaleFactor;
+	const UINT32 scaledHeight = height * scaleFactor;
+	return D2D1::SizeU(scaledWidth, scaledHeight);
+}
+
+}
 
 void ScintillaWin::EnsureRenderTarget(HDC hdc) {
 	if (!renderTargetValid) {
@@ -642,19 +656,15 @@ void ScintillaWin::EnsureRenderTarget(HDC hdc) {
 		RECT rc;
 		::GetClientRect(hw, &rc);
 
-		const D2D1_SIZE_U size = D2D1::SizeU(rc.right - rc.left, rc.bottom - rc.top);
-
 		// Create a Direct2D render target.
 		D2D1_RENDER_TARGET_PROPERTIES drtp {};
 		drtp.type = D2D1_RENDER_TARGET_TYPE_DEFAULT;
-		drtp.pixelFormat.format = DXGI_FORMAT_UNKNOWN;
-		drtp.pixelFormat.alphaMode = D2D1_ALPHA_MODE_UNKNOWN;
-		drtp.dpiX = 96.0;
-		drtp.dpiY = 96.0;
 		drtp.usage = D2D1_RENDER_TARGET_USAGE_NONE;
 		drtp.minLevel = D2D1_FEATURE_LEVEL_DEFAULT;
 
 		if (technology == Technology::DirectWriteDC) {
+			drtp.dpiX = 96.f;
+			drtp.dpiY = 96.f;
 			// Explicit pixel format needed.
 			drtp.pixelFormat = D2D1::PixelFormat(DXGI_FORMAT_B8G8R8A8_UNORM,
 				D2D1_ALPHA_MODE_IGNORE);
@@ -669,9 +679,14 @@ void ScintillaWin::EnsureRenderTarget(HDC hdc) {
 			}
 
 		} else {
+			drtp.dpiX = 96.f * deviceScaleFactor;
+			drtp.dpiY = 96.f * deviceScaleFactor;
+			drtp.pixelFormat = D2D1::PixelFormat(DXGI_FORMAT_UNKNOWN,
+				D2D1_ALPHA_MODE_UNKNOWN);
+
 			D2D1_HWND_RENDER_TARGET_PROPERTIES dhrtp {};
 			dhrtp.hwnd = hw;
-			dhrtp.pixelSize = size;
+			dhrtp.pixelSize = ::GetSizeUFromRect(rc, deviceScaleFactor);
 			dhrtp.presentOptions = (technology == Technology::DirectWriteRetain) ?
 			D2D1_PRESENT_OPTIONS_RETAIN_CONTENTS : D2D1_PRESENT_OPTIONS_NONE;
 
@@ -3594,10 +3609,12 @@ LRESULT PASCAL ScintillaWin::CTWndProc(
 					surfaceWindow->Init(ps.hdc, hWnd);
 				} else {
 #if defined(USE_D2D)
+					const int scaleFactor = sciThis->deviceScaleFactor;
+
 					// Create a Direct2D render target.
 					D2D1_HWND_RENDER_TARGET_PROPERTIES dhrtp {};
 					dhrtp.hwnd = hWnd;
-					dhrtp.pixelSize = D2D1::SizeU(rc.right - rc.left, rc.bottom - rc.top);
+					dhrtp.pixelSize = ::GetSizeUFromRect(rc, scaleFactor);
 					dhrtp.presentOptions = (sciThis->technology == Technology::DirectWriteRetain) ?
 						D2D1_PRESENT_OPTIONS_RETAIN_CONTENTS : D2D1_PRESENT_OPTIONS_NONE;
 
@@ -3605,8 +3622,8 @@ LRESULT PASCAL ScintillaWin::CTWndProc(
 					drtp.type = D2D1_RENDER_TARGET_TYPE_DEFAULT;
 					drtp.pixelFormat.format = DXGI_FORMAT_UNKNOWN;
 					drtp.pixelFormat.alphaMode = D2D1_ALPHA_MODE_UNKNOWN;
-					drtp.dpiX = 96.0;
-					drtp.dpiY = 96.0;
+					drtp.dpiX = 96.f * scaleFactor;
+					drtp.dpiY = 96.f * scaleFactor;
 					drtp.usage = D2D1_RENDER_TARGET_USAGE_NONE;
 					drtp.minLevel = D2D1_FEATURE_LEVEL_DEFAULT;