[DirectWrite] Set minimum anti-aliased font size on a per script basis

Source/platform/fonts/win/FontCacheSkiaWin.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Computer, Inc.
  * Copyright (c) 2006, 2007, 2008, 2009, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 24 matching lines @@
 #include "RuntimeEnabledFeatures.h"
 #include "SkFontMgr.h"
 #include "SkTypeface_win.h"
 #include "platform/fonts/FontDescription.h"
 #include "platform/fonts/SimpleFontData.h"
 #include "platform/fonts/harfbuzz/FontPlatformDataHarfbuzz.h"
 #include "platform/fonts/win/FontFallbackWin.h"
 
 namespace WebCore {
 
-// Minimum size, in pixels, at which anti alias is enabled for certain
-// scripts. Only applies to the Direct Write backend for now.
-static const unsigned s_minSizeForComplexScriptsAntiAlias = 32;
-
 FontCache::FontCache()
     : m_purgePreventCount(0)
 {
     SkFontMgr* fontManager;
 
     if (s_useDirectWrite) {
         fontManager = SkFontMgr_New_DirectWrite();
     } else {
         fontManager = SkFontMgr_New_GDI();
         // Subpixel text positioning is not supported by the GDI backend.
@@ skipping 125 matching lines @@
     if (!matchesRequestedFamily) {
         SkString familyName;
         tf->getFamilyName(&familyName);
         if (equalIgnoringCase(family, familyName))
             matchesRequestedFamily = true;
     }
 
     return matchesRequestedFamily;
 }
 
+// Minimum size, in pixels, at which anti alias is enabled for certain
+// scripts. Only applies to the Direct Write backend for now.
+static unsigned minSizeForAntiAlias(UScriptCode script)
+{
+    switch (script) {
+    case USCRIPT_TRADITIONAL_HAN:
+        return 24;
+    case USCRIPT_SIMPLIFIED_HAN:
+    case USCRIPT_HIRAGANA:
+    case USCRIPT_KATAKANA:
+    case USCRIPT_KATAKANA_OR_HIRAGANA:
+    case USCRIPT_HANGUL:
+    case USCRIPT_BENGALI:
+        return 16;
+    case USCRIPT_THAI:
+    case USCRIPT_HEBREW:
+    case USCRIPT_ARABIC:
+    case USCRIPT_DEVANAGARI:
+    case USCRIPT_GURMUKHI:
+    case USCRIPT_GUJARATI:
+    case USCRIPT_TAMIL:
+    case USCRIPT_TELUGU:
+    case USCRIPT_KANNADA:
+    case USCRIPT_GEORGIAN:
+    case USCRIPT_ARMENIAN:
+    case USCRIPT_THAANA:
+    case USCRIPT_CANADIAN_ABORIGINAL:
+    case USCRIPT_CHEROKEE:
+    case USCRIPT_MONGOLIAN:
+    default:
+        return 0;
+    }
+}
+
 FontPlatformData* FontCache::createFontPlatformData(const FontDescription& fontDescription, const AtomicString& family, float fontSize)
 {
     CString name;
     RefPtr<SkTypeface> tf = createTypeface(fontDescription, family, name);
     if (!tf)
         return 0;
 
     // Windows will always give us a valid pointer here, even if the face name
     // is non-existent. We have to double-check and see if the family name was
     // really used.
     // FIXME: Do we need to use predefined fonts "guaranteed" to exist
     // when we're running in layout-test mode?
     if (!typefacesMatchesFamily(tf.get(), family)) {
         return 0;
     }
 
     FontPlatformData* result = new FontPlatformData(tf,
         name.data(),
         fontSize,
         fontDescription.weight() >= FontWeightBold && !tf->isBold() || fontDescription.isSyntheticBold(),
         fontDescription.style() == FontStyleItalic && !tf->isItalic() || fontDescription.isSyntheticItalic(),
         fontDescription.orientation(),
         s_useSubpixelPositioning);
 
-    // FIXME: Turn this into a script to min-size table.
-    if (s_useDirectWrite
-        && (fontDescription.script() == USCRIPT_SIMPLIFIED_HAN
-            || fontDescription.script() == USCRIPT_TRADITIONAL_HAN
-            || fontDescription.script() == USCRIPT_HIRAGANA
-            || fontDescription.script() == USCRIPT_KATAKANA
-            || fontDescription.script() == USCRIPT_KATAKANA_OR_HIRAGANA
-            || fontDescription.script() == USCRIPT_HANGUL
-            || fontDescription.script() == USCRIPT_THAI
-            || fontDescription.script() == USCRIPT_HEBREW
-            || fontDescription.script() == USCRIPT_ARABIC
-            || fontDescription.script() == USCRIPT_DEVANAGARI
-            || fontDescription.script() == USCRIPT_BENGALI
-            || fontDescription.script() == USCRIPT_GURMUKHI
-            || fontDescription.script() == USCRIPT_GUJARATI
-            || fontDescription.script() == USCRIPT_TAMIL
-            || fontDescription.script() == USCRIPT_TELUGU
-            || fontDescription.script() == USCRIPT_KANNADA
-            || fontDescription.script() == USCRIPT_GEORGIAN
-            || fontDescription.script() == USCRIPT_ARMENIAN
-            || fontDescription.script() == USCRIPT_THAANA
-            || fontDescription.script() == USCRIPT_CANADIAN_ABORIGINAL
-            || fontDescription.script() == USCRIPT_CHEROKEE
-            || fontDescription.script() == USCRIPT_MONGOLIAN)) {
-        result->setMinSizeForAntiAlias(s_minSizeForComplexScriptsAntiAlias);
+    if (s_useDirectWrite) {
+        result->setMinSizeForAntiAlias(
+            minSizeForAntiAlias(fontDescription.script()));
     }
 
     return result;
 }
 
 }