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

Source/platform/fonts/mac/FontCacheMac.mm

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  *
  * 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.
@@ skipping 13 matching lines @@
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #import "config.h"
 #import "platform/fonts/FontCache.h"
 
 #import <AppKit/AppKit.h>
+#import "RuntimeEnabledFeatures.h"
 #import "platform/LayoutTestSupport.h"
 #import "platform/fonts/FontDescription.h"
 #import "platform/fonts/FontPlatformData.h"
 #import "platform/fonts/SimpleFontData.h"
 #import "platform/mac/WebFontCache.h"
 #import <wtf/MainThread.h>
 #import <wtf/StdLibExtras.h>
 
 // Forward declare Mac SPIs.
 // Request for public API: rdar://13803570
@@ skipping 14 matching lines @@
     FontCache::fontCache()->invalidate();
 }
 
 static void fontCacheRegisteredFontsChangedNotificationCallback(CFNotificationCenterRef, void* observer, CFStringRef name, const void *, CFDictionaryRef)
 {
     ASSERT_UNUSED(observer, observer == FontCache::fontCache());
     ASSERT_UNUSED(name, CFEqual(name, kCTFontManagerRegisteredFontsChangedNotification));
     invalidateFontCache(0);
 }
 
+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();
+}
+
 void FontCache::platformInit()
 {
     CFNotificationCenterAddObserver(CFNotificationCenterGetLocalCenter(), this, fontCacheRegisteredFontsChangedNotificationCallback, kCTFontManagerRegisteredFontsChangedNotification, 0, CFNotificationSuspensionBehaviorDeliverImmediately);
 }
 
 static int toAppKitFontWeight(FontWeight fontWeight)
 {
     static int appKitFontWeights[] = {
         2,  // FontWeight100
         3,  // FontWeight200
@@ skipping 76 matching lines @@
     NSInteger substituteFontWeight = [fontManager weightOfFont:substituteFont];
 
     if (traits != substituteFontTraits || weight != substituteFontWeight || !nsFont) {
         if (NSFont *bestVariation = [fontManager fontWithFamily:[substituteFont familyName] traits:traits weight:weight size:size]) {
             if (!nsFont || (([fontManager traitsOfFont:bestVariation] != substituteFontTraits || [fontManager weightOfFont:bestVariation] != substituteFontWeight)
                 && [[bestVariation coveredCharacterSet] longCharacterIsMember:character]))
                 substituteFont = bestVariation;
         }
     }
 
-    // Enable hinting, which is equivalent to using the screen font,
-    // only when running the set of standard non-subpixel layout tests,
-    // otherwise use subpixel glyph positioning.
-    substituteFont = !isRunningLayoutTest() || isFontAntialiasingEnabledForTest() ? [substituteFont printerFont] : [substituteFont screenFont];
+    substituteFont = useHinting() ? [substituteFont screenFont] : [substituteFont printerFont];
 
     substituteFontTraits = [fontManager traitsOfFont:substituteFont];
     substituteFontWeight = [fontManager weightOfFont:substituteFont];
 
     FontPlatformData alternateFont(substituteFont, platformData.size(),
         isAppKitFontWeightBold(weight) && !isAppKitFontWeightBold(substituteFontWeight),
         (traits & NSFontItalicTrait) && !(substituteFontTraits & NSFontItalicTrait),
         platformData.m_orientation);
 
     return fontDataFromFontPlatformData(&alternateFont, DoNotRetain);
@@ skipping 26 matching lines @@
     NSFont *nsFont = [WebFontCache fontWithFamily:family traits:traits weight:weight size:size];
     if (!nsFont)
         return 0;
 
     NSFontManager *fontManager = [NSFontManager sharedFontManager];
     NSFontTraitMask actualTraits = 0;
     if (fontDescription.style())
         actualTraits = [fontManager traitsOfFont:nsFont];
     NSInteger actualWeight = [fontManager weightOfFont:nsFont];
 
-    // Enable hinting, which is equivalent to using the screen font,
-    // only when running the set of standard non-subpixel layout tests,
-    // otherwise use subpixel glyph positioning.
-    NSFont *platformFont = !isRunningLayoutTest() || isFontAntialiasingEnabledForTest() ? [nsFont printerFont] : [nsFont screenFont];
+    NSFont *platformFont = useHinting() ? [nsFont screenFont] : [nsFont printerFont];
     bool syntheticBold = (isAppKitFontWeightBold(weight) && !isAppKitFontWeightBold(actualWeight)) || fontDescription.isSyntheticBold();
     bool syntheticOblique = ((traits & NSFontItalicTrait) && !(actualTraits & NSFontItalicTrait)) || fontDescription.isSyntheticItalic();
 
     // FontPlatformData::font() can be null for the case of Chromium out-of-process font loading.
     // In that case, we don't want to use the platformData.
     OwnPtr<FontPlatformData> platformData = adoptPtr(new FontPlatformData(platformFont, size, syntheticBold, syntheticOblique, fontDescription.orientation(), fontDescription.widthVariant()));
     if (!platformData->font())
         return 0;
     return platformData.leakPtr();
 }
 
 } // namespace WebCore