Bug 1321901 - Use IDWriteFontFace::GetRecommendedRenderingMode for font rendering mode in Skia. r=lsalzman

gfx/skia/skia/src/ports/SkScalerContext_win_dw.cpp

@@ -219,7 +219,13 @@ SkScalerContext_DW::SkScalerContext_DW(DWriteFontTypeface* typeface,
     fIsColorFont = fFactory2.get() && fontFace2.get() && fontFace2->IsColorFont();
 #endif
 
-    // In general, all glyphs should use CLEARTYPE_NATURAL_SYMMETRIC
+    IDWriteFactory* factory = sk_get_dwrite_factory();
+    if (factory != nullptr) {
+        HRVM(factory->CreateRenderingParams(&fDefaultRenderingParams),
+        "Could not create default rendering params");
+    }
+
+    // In general, all glyphs should DWriteFontFace::GetRecommendedRenderingMode
     // except when bi-level rendering is requested or there are embedded
     // bi-level bitmaps (and the embedded bitmap flag is set and no rotation).
     //
@@ -315,13 +321,26 @@ SkScalerContext_DW::SkScalerContext_DW(DWriteFontTypeface* typeface,
         fTextSizeMeasure = realTextSize;
         fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
 
-    // The normal case is to use natural symmetric rendering and linear metrics.
+    // The normal case is to use the recommended rendering mode
     } else {
         fTextSizeRender = realTextSize;
-        fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
         fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
         fTextSizeMeasure = realTextSize;
         fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
+
+        if (!SUCCEEDED(fTypeface->fDWriteFontFace->GetRecommendedRenderingMode(
+                fTextSizeRender,
+                1.0f,
+                fMeasuringMode,
+                fDefaultRenderingParams.get(),
+                &fRenderingMode))) {
+            fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
+        }
+
+        // We don't support outline mode right now.
+        if (fRenderingMode == DWRITE_RENDERING_MODE_OUTLINE) {
+            fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
+        }
     }
 
     if (this->isSubpixel()) {

gfx/skia/skia/src/ports/SkScalerContext_win_dw.h

@@ -75,6 +75,7 @@ private:
     DWRITE_RENDERING_MODE fRenderingMode;
     DWRITE_TEXTURE_TYPE fTextureType;
     DWRITE_MEASURING_MODE fMeasuringMode;
+    SkTScopedComPtr<IDWriteRenderingParams> fDefaultRenderingParams;
 #if SK_HAS_DWRITE_2_H
     SkTScopedComPtr<IDWriteFactory2> fFactory2;
     bool fIsColorFont;

layout/reftests/w3c-css/submitted/text-decor-3/reftest.list

@@ -3,7 +3,7 @@
 
 # text-emphasis-style
 == text-emphasis-style-property-001.html text-emphasis-style-property-001-ref.html
-fuzzy-if(gtkWidget,3,4) fuzzy-if(skiaContent,87,80)  == text-emphasis-style-property-002.html text-emphasis-style-property-002-ref.html
+fuzzy-if(gtkWidget,3,4) fuzzy-if(skiaContent,103,80)  == text-emphasis-style-property-002.html text-emphasis-style-property-002-ref.html
 skip-if(/^Windows\x20NT\x205\.1/.test(http.oscpu)) == text-emphasis-style-property-003.html text-emphasis-style-property-003-ref.html
 skip-if(/^Windows\x20NT\x205\.1/.test(http.oscpu)) == text-emphasis-style-property-004.html text-emphasis-style-property-004-ref.html
 == text-emphasis-style-property-005.html text-emphasis-style-property-005-ref.html
@@ -53,7 +53,7 @@ fuzzy-if(gtkWidget,3,4) == text-emphasis-color-property-002.html text-emphasis-c
 
 # text-emphasis
 == text-emphasis-property-001.html text-emphasis-style-property-001-ref.html
-fuzzy-if(gtkWidget,3,4) fuzzy-if(skiaContent,87,80) == text-emphasis-property-002.html text-emphasis-style-property-002-ref.html
+fuzzy-if(gtkWidget,3,4) fuzzy-if(skiaContent,103,80) == text-emphasis-property-002.html text-emphasis-style-property-002-ref.html
 fuzzy-if(gtkWidget,3,4) == text-emphasis-property-003.html text-emphasis-style-property-012-ref.html
 fuzzy-if(gtkWidget,3,4) == text-emphasis-property-003a.html text-emphasis-style-property-012-ref.html
 fuzzy-if(gtkWidget,3,4) == text-emphasis-property-003b.html text-emphasis-style-property-012-ref.html