Feature [feature-requests:#1432] Support per-monitor text rendering parameters

and update when changed by user.
Includes code from Zufu Liu.

3 files changed, 100 insertions, 35 deletions

diff --git a/win32/PlatWin.cxx b/win32/PlatWin.cxx
index 3d8595b1d..af1e41b5f 100644
--- a/win32/PlatWin.cxx
+++ b/win32/PlatWin.cxx
@@ -72,8 +72,6 @@ UINT CodePageFromCharSet(CharacterSet characterSet, UINT documentCodePage) noexc
 #if defined(USE_D2D)
 IDWriteFactory *pIDWriteFactory = nullptr;
 ID2D1Factory *pD2DFactory = nullptr;
-IDWriteRenderingParams *defaultRenderingParams = nullptr;
-IDWriteRenderingParams *customClearTypeRenderingParams = nullptr;
 D2D1_DRAW_TEXT_OPTIONS d2dDrawTextOptions = D2D1_DRAW_TEXT_OPTIONS_NONE;
 
 static HMODULE hDLLD2D {};
@@ -123,24 +121,6 @@ void LoadD2DOnce() noexcept {
 				reinterpret_cast<IUnknown**>(&pIDWriteFactory));
 		}
 	}
-
-	if (pIDWriteFactory) {
-		const HRESULT hr = pIDWriteFactory->CreateRenderingParams(&defaultRenderingParams);
-		if (SUCCEEDED(hr)) {
-			unsigned int clearTypeContrast = 0;
-			if (::SystemParametersInfo(SPI_GETFONTSMOOTHINGCONTRAST, 0, &clearTypeContrast, 0)) {
-
-				FLOAT gamma;
-				if (clearTypeContrast >= 1000 && clearTypeContrast <= 2200)
-					gamma = static_cast<FLOAT>(clearTypeContrast) / 1000.0f;
-				else
-					gamma = defaultRenderingParams->GetGamma();
-
-				pIDWriteFactory->CreateCustomRenderingParams(gamma, defaultRenderingParams->GetEnhancedContrast(), defaultRenderingParams->GetClearTypeLevel(),
-					defaultRenderingParams->GetPixelGeometry(), defaultRenderingParams->GetRenderingMode(), &customClearTypeRenderingParams);
-			}
-		}
-	}
 }
 
 bool LoadD2D() {
@@ -1294,7 +1274,7 @@ constexpr D2D1_RECT_F RectangleInset(D2D1_RECT_F rect, FLOAT inset) noexcept {
 
 class BlobInline;
 
-class SurfaceD2D : public Surface {
+class SurfaceD2D : public Surface, public ISetRenderingParams {
 	SurfaceMode mode;
 
 	ID2D1RenderTarget *pRenderTarget = nullptr;
@@ -1304,8 +1284,10 @@ class SurfaceD2D : public Surface {
 
 	ID2D1SolidColorBrush *pBrush = nullptr;
 
-	FontQuality fontQuality = FontQuality::QualityMask;
+	static constexpr FontQuality invalidFontQuality = FontQuality::QualityMask;
+	FontQuality fontQuality = invalidFontQuality;
 	int logPixelsY = USER_DEFAULT_SCREEN_DPI;
+	std::shared_ptr<RenderingParams> renderingParams;
 
 	void Clear() noexcept;
 	void SetFontQuality(FontQuality extraFontFlag);
@@ -1379,6 +1361,8 @@ public:
 	void PopClip() override;
 	void FlushCachedState() override;
 	void FlushDrawing() override;
+
+	void SetRenderingParams(std::shared_ptr<RenderingParams> renderingParams_) override;
 };
 
 SurfaceD2D::SurfaceD2D() noexcept {
@@ -1430,7 +1414,7 @@ void SurfaceD2D::Release() noexcept {
 }
 
 void SurfaceD2D::SetScale(WindowID wid) noexcept {
-	fontQuality = FontQuality::QualityMask;
+	fontQuality = invalidFontQuality;
 	logPixelsY = DpiForWindow(wid);
 }
 
@@ -1458,7 +1442,9 @@ void SurfaceD2D::Init(SurfaceID sid, WindowID wid) {
 }
 
 std::unique_ptr<Surface> SurfaceD2D::AllocatePixMap(int width, int height) {
-	return std::make_unique<SurfaceD2D>(pRenderTarget, width, height, mode, logPixelsY);
+	std::unique_ptr<SurfaceD2D> surf = std::make_unique<SurfaceD2D>(pRenderTarget, width, height, mode, logPixelsY);
+	surf->SetRenderingParams(renderingParams);
+	return surf;
 }
 
 void SurfaceD2D::SetMode(SurfaceMode mode_) {
@@ -1485,15 +1471,14 @@ void SurfaceD2D::D2DPenColourAlpha(ColourRGBA fore) noexcept {
 }
 
 void SurfaceD2D::SetFontQuality(FontQuality extraFontFlag) {
-	if (fontQuality != extraFontFlag) {
+	if ((fontQuality != extraFontFlag) && renderingParams) {
 		fontQuality = extraFontFlag;
 		const D2D1_TEXT_ANTIALIAS_MODE aaMode = DWriteMapFontQuality(extraFontFlag);
-
-		if (aaMode == D2D1_TEXT_ANTIALIAS_MODE_CLEARTYPE && customClearTypeRenderingParams)
-			pRenderTarget->SetTextRenderingParams(customClearTypeRenderingParams);
-		else if (defaultRenderingParams)
-			pRenderTarget->SetTextRenderingParams(defaultRenderingParams);
-
+		if (aaMode == D2D1_TEXT_ANTIALIAS_MODE_CLEARTYPE && renderingParams->customRenderingParams) {
+			pRenderTarget->SetTextRenderingParams(renderingParams->customRenderingParams.get());
+		} else if (renderingParams->defaultRenderingParams) {
+			pRenderTarget->SetTextRenderingParams(renderingParams->defaultRenderingParams.get());
+		}
 		pRenderTarget->SetTextAntialiasMode(aaMode);
 	}
 }
@@ -2629,6 +2614,10 @@ void SurfaceD2D::FlushDrawing() {
 	}
 }
 
+void SurfaceD2D::SetRenderingParams(std::shared_ptr<RenderingParams> renderingParams_) {
+	renderingParams = renderingParams_;
+}
+
 #endif
 
 std::unique_ptr<Surface> Surface::Allocate(Technology technology) {
@@ -3863,8 +3852,6 @@ void Platform_Initialise(void *hInstance) noexcept {
 void Platform_Finalise(bool fromDllMain) noexcept {
 #if defined(USE_D2D)
 	if (!fromDllMain) {
-		ReleaseUnknown(defaultRenderingParams);
-		ReleaseUnknown(customClearTypeRenderingParams);
 		ReleaseUnknown(pIDWriteFactory);
 		ReleaseUnknown(pD2DFactory);
 		if (hDLLDWrite) {
diff --git a/win32/PlatWin.h b/win32/PlatWin.h
index 68b5dd9ef..893618b38 100644
--- a/win32/PlatWin.h
+++ b/win32/PlatWin.h
@@ -53,6 +53,15 @@ HCURSOR LoadReverseArrowCursor(UINT dpi) noexcept;
 extern bool LoadD2D();
 extern ID2D1Factory *pD2DFactory;
 extern IDWriteFactory *pIDWriteFactory;
+
+struct RenderingParams {
+	std::unique_ptr<IDWriteRenderingParams, UnknownReleaser> defaultRenderingParams;
+	std::unique_ptr<IDWriteRenderingParams, UnknownReleaser> customRenderingParams;
+};
+
+struct ISetRenderingParams {
+	virtual void SetRenderingParams(std::shared_ptr<RenderingParams> renderingParams_) = 0;
+};
 #endif
 
 }
diff --git a/win32/ScintillaWin.cxx b/win32/ScintillaWin.cxx
index 7bb8d43db..52473bfa6 100644
--- a/win32/ScintillaWin.cxx
+++ b/win32/ScintillaWin.cxx
@@ -318,6 +318,9 @@ class ScintillaWin :
 #if defined(USE_D2D)
 	ID2D1RenderTarget *pRenderTarget;
 	bool renderTargetValid;
+	// rendering parameters for current monitor
+	HMONITOR hCurrentMonitor;
+	std::shared_ptr<RenderingParams> renderingParams;
 #endif
 
 	explicit ScintillaWin(HWND hwnd);
@@ -330,6 +333,7 @@ class ScintillaWin :
 
 	void Finalise() override;
 #if defined(USE_D2D)
+	bool UpdateRenderingParams(bool force) noexcept;
 	void EnsureRenderTarget(HDC hdc);
 #endif
 	void DropRenderTarget() noexcept;
@@ -354,6 +358,8 @@ class ScintillaWin :
 	Sci::Position TargetAsUTF8(char *text) const;
 	Sci::Position EncodedFromUTF8(const char *utf8, char *encoded) const;
 
+	void SetRenderingParams(Surface *psurf) const;
+
 	bool PaintDC(HDC hdc);
 	sptr_t WndPaint();
 
@@ -533,6 +539,7 @@ ScintillaWin::ScintillaWin(HWND hwnd) {
 #if defined(USE_D2D)
 	pRenderTarget = nullptr;
 	renderTargetValid = true;
+	hCurrentMonitor = {};
 #endif
 
 	caret.period = ::GetCaretBlinkTime();
@@ -577,6 +584,38 @@ void ScintillaWin::Finalise() {
 
 #if defined(USE_D2D)
 
+bool ScintillaWin::UpdateRenderingParams(bool force) noexcept {
+	if (!renderingParams) {
+		renderingParams = std::make_shared<RenderingParams>();
+	}
+	HMONITOR monitor = ::MonitorFromWindow(MainHWND(), MONITOR_DEFAULTTONEAREST);
+	if (!force && monitor == hCurrentMonitor && renderingParams->defaultRenderingParams) {
+		return false;
+	}
+
+	IDWriteRenderingParams *monitorRenderingParams = nullptr;
+	IDWriteRenderingParams *customClearTypeRenderingParams = nullptr;
+	const HRESULT hr = pIDWriteFactory->CreateMonitorRenderingParams(monitor, &monitorRenderingParams);
+	UINT clearTypeContrast = 0;
+	if (SUCCEEDED(hr) && ::SystemParametersInfo(SPI_GETFONTSMOOTHINGCONTRAST, 0, &clearTypeContrast, 0) != 0) {
+		if (clearTypeContrast >= 1000 && clearTypeContrast <= 2200) {
+			const FLOAT gamma = static_cast<FLOAT>(clearTypeContrast) / 1000.0f;
+			pIDWriteFactory->CreateCustomRenderingParams(gamma,
+				monitorRenderingParams->GetEnhancedContrast(),
+				monitorRenderingParams->GetClearTypeLevel(),
+				monitorRenderingParams->GetPixelGeometry(),
+				monitorRenderingParams->GetRenderingMode(),
+				&customClearTypeRenderingParams);
+		}
+	}
+
+	hCurrentMonitor = monitor;
+	renderingParams->defaultRenderingParams.reset(monitorRenderingParams);
+	renderingParams->customRenderingParams.reset(customClearTypeRenderingParams);
+	return true;
+}
+
+
 void ScintillaWin::EnsureRenderTarget(HDC hdc) {
 	if (!renderTargetValid) {
 		DropRenderTarget();
@@ -646,7 +685,6 @@ void ScintillaWin::EnsureRenderTarget(HDC hdc) {
 }
 #endif
 
-
 void ScintillaWin::DropRenderTarget() noexcept {
 #if defined(USE_D2D)
 	ReleaseUnknown(pRenderTarget);
@@ -873,6 +911,17 @@ Sci::Position ScintillaWin::EncodedFromUTF8(const char *utf8, char *encoded) con
 	}
 }
 
+void ScintillaWin::SetRenderingParams([[maybe_unused]] Surface *psurf) const {
+#if defined(USE_D2D)
+	if (psurf) {
+		ISetRenderingParams *setDrawingParams = dynamic_cast<ISetRenderingParams *>(psurf);
+		if (setDrawingParams) {
+			setDrawingParams->SetRenderingParams(renderingParams);
+		}
+	}
+#endif
+}
+
 bool ScintillaWin::PaintDC(HDC hdc) {
 	if (technology == Technology::Default) {
 		AutoSurface surfaceWindow(hdc, this);
@@ -886,6 +935,7 @@ bool ScintillaWin::PaintDC(HDC hdc) {
 		if (pRenderTarget) {
 			AutoSurface surfaceWindow(pRenderTarget, this);
 			if (surfaceWindow) {
+				SetRenderingParams(surfaceWindow);
 				pRenderTarget->BeginDraw();
 				Paint(surfaceWindow, rcPaint);
 				surfaceWindow->Release();
@@ -1824,9 +1874,11 @@ sptr_t ScintillaWin::SciMessage(Message iMessage, uptr_t wParam, sptr_t lParam)
 			if (technology != technologyNew) {
 				if (technologyNew > Technology::Default) {
 #if defined(USE_D2D)
-					if (!LoadD2D())
+					if (!LoadD2D()) {
 						// Failed to load Direct2D or DirectWrite so no effect
 						return 0;
+					}
+					UpdateRenderingParams(true);
 #else
 					return 0;
 #endif
@@ -1952,6 +2004,12 @@ sptr_t ScintillaWin::WndProc(Message iMessage, uptr_t wParam, sptr_t lParam) {
 
 		case WM_SETTINGCHANGE:
 			//Platform::DebugPrintf("Setting Changed\n");
+#if defined(USE_D2D)
+			if (technology != Technology::Default) {
+				UpdateRenderingParams(true);
+				Redraw();
+			}
+#endif
 			UpdateBaseElements();
 			InvalidateStyleData();
 			// Get Intellimouse scroll line parameters
@@ -2016,7 +2074,17 @@ sptr_t ScintillaWin::WndProc(Message iMessage, uptr_t wParam, sptr_t lParam) {
 		case WM_NCLBUTTONDOWN:
 		case WM_SYSCOMMAND:
 		case WM_WINDOWPOSCHANGING:
+			return ::DefWindowProc(MainHWND(), msg, wParam, lParam);
+
 		case WM_WINDOWPOSCHANGED:
+#if defined(USE_D2D)
+			if (technology != Technology::Default) {
+				if (UpdateRenderingParams(false)) {
+					DropGraphics();
+					Redraw();
+				}
+			}
+#endif
 			return ::DefWindowProc(MainHWND(), msg, wParam, lParam);
 
 		case WM_GETTEXTLENGTH:
@@ -3528,6 +3596,7 @@ LRESULT PASCAL ScintillaWin::CTWndProc(
 #endif
 				}
 				surfaceWindow->SetMode(sciThis->CurrentSurfaceMode());
+				sciThis->SetRenderingParams(surfaceWindow.get());
 				sciThis->ct.PaintCT(surfaceWindow.get());
 #if defined(USE_D2D)
 				if (pCTRenderTarget)