[Skia] Handle font smoothing when drawing glyphs

https://bugs.webkit.org/show_bug.cgi?id=273367

Reviewed by Alejandro G. Castro.

* Source/WebCore/platform/graphics/skia/FontCascadeSkia.cpp:
(WebCore::FontCascade::drawGlyphs):

Canonical link: https://commits.webkit.org/278101@main

Source/WebCore/platform/graphics/skia/FontCascadeSkia.cpp

@@ -35,16 +35,43 @@
 
 namespace WebCore {
 
-void FontCascade::drawGlyphs(GraphicsContext& graphicsContext, const Font& font, const GlyphBufferGlyph* glyphs, const GlyphBufferAdvance* advances, unsigned glyphCount, const FloatPoint& position, FontSmoothingMode)
+void FontCascade::drawGlyphs(GraphicsContext& graphicsContext, const Font& font, const GlyphBufferGlyph* glyphs, const GlyphBufferAdvance* advances, unsigned glyphCount, const FloatPoint& position, FontSmoothingMode smoothingMode)
 {
     if (!font.platformData().size())
         return;
 
     const auto& fontPlatformData = font.platformData();
     const auto& skFont = fontPlatformData.skFont();
-    SkTextBlobBuilder builder;
+
+    if (!font.allowsAntialiasing())
+        smoothingMode = FontSmoothingMode::NoSmoothing;
+
+    SkFont::Edging edging;
+    switch (smoothingMode) {
+    case FontSmoothingMode::AutoSmoothing:
+        edging = skFont.getEdging();
+        break;
+    case FontSmoothingMode::Antialiased:
+        edging = SkFont::Edging::kAntiAlias;
+        break;
+    case FontSmoothingMode::SubpixelAntialiased:
+        edging = SkFont::Edging::kSubpixelAntiAlias;
+        break;
+    case FontSmoothingMode::NoSmoothing:
+        edging = SkFont::Edging::kAlias;
+        break;
+    }
+
     bool isVertical = fontPlatformData.orientation() == FontOrientation::Vertical;
-    const auto& buffer = isVertical ? builder.allocRunPos(skFont, glyphCount) : builder.allocRunPosH(skFont, glyphCount, 0);
+    SkTextBlobBuilder builder;
+    const auto& buffer = [&]() {
+        if (skFont.getEdging() == edging)
+            return isVertical ? builder.allocRunPos(skFont, glyphCount) : builder.allocRunPosH(skFont, glyphCount, 0);
+
+        SkFont copiedFont = skFont;
+        copiedFont.setEdging(edging);
+        return isVertical ? builder.allocRunPos(copiedFont, glyphCount) : builder.allocRunPosH(copiedFont, glyphCount, 0);
+    }();
 
     FloatSize glyphPosition;
     for (unsigned i = 0; i < glyphCount; ++i) {
@@ -74,15 +101,15 @@ void FontCascade::drawGlyphs(GraphicsContext& graphicsContext, const Font& font,
 
     if (graphicsContext.textDrawingMode().contains(TextDrawingMode::Fill)) {
         SkPaint paint = skiaGraphicsContext->createFillPaint();
-        paint.setAntiAlias(font.allowsAntialiasing());
+        paint.setAntiAlias(edging != SkFont::Edging::kAlias);
         paint.setImageFilter(skiaGraphicsContext->createDropShadowFilterIfNeeded(GraphicsContextSkia::ShadowStyle::Outset));
         skiaGraphicsContext->setupFillSource(paint);
         canvas->drawTextBlob(blob, SkFloatToScalar(position.x()), SkFloatToScalar(position.y()), paint);
     }
 
     if (graphicsContext.textDrawingMode().contains(TextDrawingMode::Stroke)) {
         SkPaint paint = skiaGraphicsContext->createStrokePaint();
-        paint.setAntiAlias(font.allowsAntialiasing());
+        paint.setAntiAlias(edging != SkFont::Edging::kAlias);
         skiaGraphicsContext->setupStrokeSource(paint);
         canvas->drawTextBlob(blob, SkFloatToScalar(position.x()), SkFloatToScalar(position.y()), paint);
     }