Changeset 31356 for trunk/WebCore/platform/graphics/mac/FontMac.mm

Timestamp:

03/26/08 21:02:07 (8 months ago)

Author:

mitz@apple.com

Message:

Reviewed by Dave Hyatt.

• maintain subpixel-antialiasing when drawing text with a simple shadow

• platform/graphics/mac/FontMac.mm: (WebCore::Font::drawComplexText): If the shadow has a zero blur radius, draw the shadow by drawing the text at an offset instead of relying on Core Graphics shadows. (WebCore::Font::drawGlyphs): Ditto.
• platform/graphics/win/FontCGWin.cpp: (WebCore::Font::drawGlyphs): Ditto.

Files:

• trunk/WebCore/platform/graphics/mac/FontMac.mm (modified) (4 diffs)

trunk/WebCore/platform/graphics/mac/FontMac.mm

@@ -528 +528 @@
     // ATSUI can't draw beyond -32768 to +32767 so we translate the CTM and tell ATSUI to draw at (0, 0).
     CGContextRef context = graphicsContext->platformContext();
-
     CGContextTranslateCTM(context, point.x(), point.y());
+
+    IntSize shadowSize;
+    int shadowBlur;
+    Color shadowColor;
+    graphicsContext->getShadow(shadowSize, shadowBlur, shadowColor);
+
+    bool hasSimpleShadow = graphicsContext->textDrawingMode() == cTextFill && shadowColor.isValid() && !shadowBlur && !shadowSize.isEmpty();
+    if (hasSimpleShadow) {
+        // Paint simple shadows ourselves instead of relying on CG shadows, to avoid losing subpixel antialiasing.
+        graphicsContext->clearShadow();
+        Color fillColor = graphicsContext->fillColor();
+        Color shadowFillColor(shadowColor.red(), shadowColor.green(), shadowColor.blue(), shadowColor.alpha() * fillColor.alpha() / 255);
+        graphicsContext->setFillColor(shadowFillColor);
+        CGContextTranslateCTM(context, shadowSize.width(), shadowSize.height());
+        status = ATSUDrawText(params.m_layout, from, drawPortionLength, 0, 0);
+        if (status == noErr && params.m_hasSyntheticBold) {
+            // Force relayout for the bold pass
+            ATSUClearLayoutCache(params.m_layout, 0);
+            params.m_syntheticBoldPass = true;
+            status = ATSUDrawText(params.m_layout, from, drawPortionLength, 0, 0);
+            // Force relayout for the next pass
+            ATSUClearLayoutCache(params.m_layout, 0);
+            params.m_syntheticBoldPass = false;
+        }
+        CGContextTranslateCTM(context, -shadowSize.width(), -shadowSize.height());
+        graphicsContext->setFillColor(fillColor);
+    }
+
     status = ATSUDrawText(params.m_layout, from, drawPortionLength, 0, 0);
     if (status == noErr && params.m_hasSyntheticBold) {
@@ -542 +569 @@
         // Nothing to do but report the error (dev build only).
         LOG_ERROR("ATSUDrawText() failed(%d)", status);
+
+    if (hasSimpleShadow)
+        graphicsContext->setShadow(shadowSize, shadowBlur, shadowColor);
 
     disposeATSULayoutParameters(&params);
@@ -645 +675 @@
     } else
         CGContextSetFontSize(cgContext, platformData.m_size);
-    
+
+    IntSize shadowSize;
+    int shadowBlur;
+    Color shadowColor;
+    context->getShadow(shadowSize, shadowBlur, shadowColor);
+
+    bool hasSimpleShadow = context->textDrawingMode() == cTextFill && shadowColor.isValid() && !shadowBlur && !shadowSize.isEmpty();
+    if (hasSimpleShadow) {
+        // Paint simple shadows ourselves instead of relying on CG shadows, to avoid losing subpixel antialiasing.
+        context->clearShadow();
+        Color fillColor = context->fillColor();
+        Color shadowFillColor(shadowColor.red(), shadowColor.green(), shadowColor.blue(), shadowColor.alpha() * fillColor.alpha() / 255);
+        context->setFillColor(shadowFillColor);
+        CGContextSetTextPosition(cgContext, point.x() + shadowSize.width(), point.y() + shadowSize.height());
+        CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
+        if (font->m_syntheticBoldOffset) {
+            CGContextSetTextPosition(cgContext, point.x() + shadowSize.width() + font->m_syntheticBoldOffset, point.y() + shadowSize.height());
+            CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
+        }
+        context->setFillColor(fillColor);
+    }
+
     CGContextSetTextPosition(cgContext, point.x(), point.y());
     CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
@@ -653 +704 @@
     }
 
+    if (hasSimpleShadow)
+        context->setShadow(shadowSize, shadowBlur, shadowColor);
+
     if (originalShouldUseFontSmoothing != newShouldUseFontSmoothing)
         CGContextSetShouldSmoothFonts(cgContext, originalShouldUseFontSmoothing);