Gate subpixel scaling by RuntimeEnabledFeatures::subpixelFontScalingEnabled() on Mac

Source/platform/fonts/mac/SimpleFontDataMac.mm

 /*
  * Copyright (C) 2005, 2006, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 13 matching lines @@
  * THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #import "config.h"
 #import "platform/fonts/SimpleFontData.h"
 
 #import <AppKit/AppKit.h>
 #import <ApplicationServices/ApplicationServices.h>
 #import <float.h>
 #import <unicode/uchar.h>
+#import "RuntimeEnabledFeatures.h"
+#import "platform/LayoutTestSupport.h"
 #import "platform/SharedBuffer.h"
 #import "platform/fonts/Font.h"
 #import "platform/fonts/FontCache.h"
 #import "platform/fonts/FontDescription.h"
 #import "platform/geometry/FloatRect.h"
 #import "platform/graphics/Color.h"
 #import "platform/mac/BlockExceptions.h"
 #import <wtf/Assertions.h>
 #import <wtf/RetainPtr.h>
 #import <wtf/StdLibExtras.h>
@@ skipping 55 matching lines @@
 
     return true;
 }
 
 static NSString *webFallbackFontFamily(void)
 {
     DEFINE_STATIC_LOCAL(RetainPtr<NSString>, webFallbackFontFamily, ([[NSFont systemFontOfSize:16.0f] familyName]));
     return webFallbackFontFamily.get();
 }
 
+static bool useHinting()
+{
+    // Enable hinting when subpixel font scaling is disabled or
+    // when running the set of standard non-subpixel layout tests,
+    // otherwise use subpixel glyph positioning.
+    return (isRunningLayoutTest() && !isFontAntialiasingEnabledForTest()) || !RuntimeEnabledFeatures::subpixelFontScalingEnabled();
+}
+
 const SimpleFontData* SimpleFontData::getCompositeFontReferenceFontData(NSFont *key) const
 {
     if (key && !CFEqual(RetainPtr<CFStringRef>(AdoptCF, CTFontCopyPostScriptName(CTFontRef(key))).get(), CFSTR("LastResort"))) {
         if (!m_derivedFontData)
             m_derivedFontData = DerivedFontData::create(isCustomFont());
         if (!m_derivedFontData->compositeFontReferences)
             m_derivedFontData->compositeFontReferences.adoptCF(CFDictionaryCreateMutable(kCFAllocatorDefault, 1, &kCFTypeDictionaryKeyCallBacks, NULL));
         else {
             const SimpleFontData* found = static_cast<const SimpleFontData*>(CFDictionaryGetValue(m_derivedFontData->compositeFontReferences.get(), static_cast<const void *>(key)));
             if (found)
@@ skipping 189 matching lines @@
     if (isCustomFont()) {
         FontPlatformData scaledFontData(m_platformData);
         scaledFontData.m_size = scaledFontData.m_size * scaleFactor;
         return SimpleFontData::create(scaledFontData, CustomFontData::create());
     }
 
     BEGIN_BLOCK_OBJC_EXCEPTIONS;
     float size = m_platformData.size() * scaleFactor;
     FontPlatformData scaledFontData([[NSFontManager sharedFontManager] convertFont:m_platformData.font() toSize:size], size, false, false, m_platformData.orientation());
 
-    // Until we replace AppKit API (NSFontManager etc.), we always want to disable hinting,
-    // so we use the printerFont here.
-    scaledFontData.setFont([scaledFontData.font() printerFont]);
+    // AppKit forgets about hinting property when scaling, so we have to remind it.
+    scaledFontData.setFont(useHinting() ? [scaledFontData.font() screenFont] : [scaledFontData.font() printerFont]);

[Dominik Röttsches, 2014/05/28 14:33:51]

This part should have been in the previous patch for removing
setUsePrinterFont() removal.

 
     if (scaledFontData.font()) {
         NSFontManager *fontManager = [NSFontManager sharedFontManager];
         NSFontTraitMask fontTraits = [fontManager traitsOfFont:m_platformData.font()];
 
         if (m_platformData.m_syntheticBold)
             fontTraits |= NSBoldFontMask;
         if (m_platformData.m_syntheticOblique)
             fontTraits |= NSItalicFontMask;
 
@@ skipping 107 matching lines @@
         RetainPtr<CGFontRef> runCGFont(AdoptCF, CTFontCopyGraphicsFont(runFont, 0));
         if (!CFEqual(runCGFont.get(), cgFont.get()))
             return false;
     }
 
     addResult.storedValue->value = true;
     return true;
 }
 
 } // namespace WebCore