Changeset 31356 in webkit

Timestamp:

Mar 26, 2008, 9:02:07 PM (17 years 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.

Location:

trunk/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/graphics/mac/FontMac.mm (modified) (4 diffs)
• platform/graphics/win/FontCGWin.cpp (modified) (2 diffs)

trunk/WebCore/ChangeLog

@@ +1 @@
+2008-03-26  Dan Bernstein  <mitz@apple.com>
+
+        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.
+
 2008-03-26  Brady Eidson  <beidson@apple.com>
 

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);

trunk/WebCore/platform/graphics/win/FontCGWin.cpp

@@ -290 +290 @@
 
     CGContextSetFontSize(cgContext, platformData.size());
+
+    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);
+        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);
+        }
+        graphicsContext->setFillColor(fillColor);
+    }
+
     CGContextSetTextPosition(cgContext, point.x(), point.y());
     CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
@@ -297 +319 @@
     }
 
+    if (hasSimpleShadow)
+        graphicsContext->setShadow(shadowSize, shadowBlur, shadowColor);
+
     wkRestoreFontSmoothingStyle(cgContext, oldFontSmoothingStyle);
 }