Bug 857142 - implement -moz-font-smoothing. r=dbaron

gfx/src/nsFont.cpp

@@ -22,6 +22,7 @@ nsFont::nsFont(const char* aName, uint8_t aStyle, uint8_t aVariant,
   weight = aWeight;
   stretch = aStretch;
   decorations = aDecoration;
+  smoothing = NS_FONT_SMOOTHING_AUTO;
   size = aSize;
   sizeAdjust = 0.0;
   kerning = NS_FONT_KERNING_AUTO;
@@ -46,6 +47,7 @@ nsFont::nsFont(const nsSubstring& aName, uint8_t aStyle, uint8_t aVariant,
   weight = aWeight;
   stretch = aStretch;
   decorations = aDecoration;
+  smoothing = NS_FONT_SMOOTHING_AUTO;
   size = aSize;
   sizeAdjust = 0.0;
   kerning = NS_FONT_KERNING_AUTO;
@@ -68,6 +70,7 @@ nsFont::nsFont(const nsFont& aOther)
   weight = aOther.weight;
   stretch = aOther.stretch;
   decorations = aOther.decorations;
+  smoothing = aOther.smoothing;
   size = aOther.size;
   sizeAdjust = aOther.sizeAdjust;
   kerning = aOther.kerning;
@@ -122,7 +125,8 @@ bool nsFont::Equals(const nsFont& aOther) const
 {
   if (BaseEquals(aOther) &&
       (variant == aOther.variant) &&
-      (decorations == aOther.decorations)) {
+      (decorations == aOther.decorations) &&
+      (smoothing == aOther.smoothing)) {
     return true;
   }
   return false;
@@ -137,6 +141,7 @@ nsFont& nsFont::operator=(const nsFont& aOther)
   weight = aOther.weight;
   stretch = aOther.stretch;
   decorations = aOther.decorations;
+  smoothing = aOther.smoothing;
   size = aOther.size;
   sizeAdjust = aOther.sizeAdjust;
   kerning = aOther.kerning;
@@ -416,6 +421,11 @@ void nsFont::AddFontFeaturesToStyle(gfxFontStyle *aStyle) const
 
   // add in features from font-feature-settings
   aStyle->featureSettings.AppendElements(fontFeatureSettings);
+
+  // enable grayscale antialiasing for text
+  if (smoothing == NS_FONT_SMOOTHING_ANTIALIASED) {
+    aStyle->useGrayscaleAntialiasing = true;
+  }
 }
 
 static bool FontEnumCallback(const nsString& aFamily, bool aGeneric, void *aData)

gfx/src/nsFont.h

@@ -71,6 +71,9 @@ struct NS_GFX nsFont {
   // line-through). The decorations can be binary or'd together.
   uint8_t decorations;
 
+  // Smoothing - controls subpixel-antialiasing (currently OSX only)
+  uint8_t smoothing;
+
   // The weight of the font; see gfxFontConstants.h.
   uint16_t weight;
 

gfx/thebes/gfxFont.cpp

@@ -5012,7 +5012,7 @@ gfxFontStyle::gfxFontStyle() :
     size(DEFAULT_PIXEL_FONT_SIZE), sizeAdjust(0.0f),
     languageOverride(NO_FONT_LANGUAGE_OVERRIDE),
     weight(NS_FONT_WEIGHT_NORMAL), stretch(NS_FONT_STRETCH_NORMAL),
-    systemFont(true), printerFont(false), 
+    systemFont(true), printerFont(false), useGrayscaleAntialiasing(false),
     style(NS_FONT_STYLE_NORMAL)
 {
 }
@@ -5027,7 +5027,7 @@ gfxFontStyle::gfxFontStyle(uint8_t aStyle, uint16_t aWeight, int16_t aStretch,
     languageOverride(ParseFontLanguageOverride(aLanguageOverride)),
     weight(aWeight), stretch(aStretch),
     systemFont(aSystemFont), printerFont(aPrinterFont),
-    style(aStyle)
+    useGrayscaleAntialiasing(false), style(aStyle)
 {
     MOZ_ASSERT(!mozilla::IsNaN(size));
     MOZ_ASSERT(!mozilla::IsNaN(sizeAdjust));
@@ -5058,6 +5058,7 @@ gfxFontStyle::gfxFontStyle(const gfxFontStyle& aStyle) :
     languageOverride(aStyle.languageOverride),
     weight(aStyle.weight), stretch(aStyle.stretch),
     systemFont(aStyle.systemFont), printerFont(aStyle.printerFont),
+    useGrayscaleAntialiasing(aStyle.useGrayscaleAntialiasing),
     style(aStyle.style)
 {
     featureSettings.AppendElements(aStyle.featureSettings);

gfx/thebes/gfxFont.h

@@ -127,6 +127,9 @@ struct gfxFontStyle {
     // Say that this font is used for print or print preview.
     bool printerFont : 1;
 
+    // Used to imitate -webkit-font-smoothing: antialiased
+    bool useGrayscaleAntialiasing : 1;
+
     // The style of font (normal, italic, oblique)
     uint8_t style : 2;
 
@@ -153,6 +156,7 @@ struct gfxFontStyle {
             (style == other.style) &&
             (systemFont == other.systemFont) &&
             (printerFont == other.printerFont) &&
+            (useGrayscaleAntialiasing == other.useGrayscaleAntialiasing) &&
             (weight == other.weight) &&
             (stretch == other.stretch) &&
             (language == other.language) &&

gfx/thebes/gfxFontConstants.h

@@ -30,6 +30,9 @@
 #define NS_FONT_STRETCH_EXTRA_EXPANDED  3
 #define NS_FONT_STRETCH_ULTRA_EXPANDED  4
 
+#define NS_FONT_SMOOTHING_AUTO          0
+#define NS_FONT_SMOOTHING_ANTIALIASED   1
+
 #define NS_FONT_KERNING_AUTO                        0
 #define NS_FONT_KERNING_NONE                        1
 #define NS_FONT_KERNING_NORMAL                      2

gfx/thebes/gfxMacFont.cpp

@@ -84,6 +84,8 @@ gfxMacFont::gfxMacFont(MacOSFontEntry *aFontEntry, const gfxFontStyle *aFontStyl
     if (mAdjustedSize <=
         (gfxFloat)gfxPlatformMac::GetPlatform()->GetAntiAliasingThreshold()) {
         cairo_font_options_set_antialias(fontOptions, CAIRO_ANTIALIAS_NONE);
+    } else if (mStyle.useGrayscaleAntialiasing) {
+        cairo_font_options_set_antialias(fontOptions, CAIRO_ANTIALIAS_GRAY);
     }
 
     mScaledFont = cairo_scaled_font_create(mFontFace, &sizeMatrix, &ctm,

layout/style/nsCSSKeywordList.h

@@ -169,6 +169,7 @@ CSS_KEY(alpha, alpha)
 CSS_KEY(alternate, alternate)
 CSS_KEY(alternate-reverse, alternate_reverse)
 CSS_KEY(always, always)
+CSS_KEY(antialiased, antialiased)
 CSS_KEY(annotation, annotation)
 CSS_KEY(appworkspace, appworkspace)
 CSS_KEY(armenian, armenian)

layout/style/nsCSSPropList.h

@@ -1760,6 +1760,18 @@ CSS_PROP_FONT(
     nullptr,
     offsetof(nsStyleFont, mFont.sizeAdjust),
     eStyleAnimType_float)
+CSS_PROP_FONT(
+    -moz-font-smoothing,
+    font_smoothing,
+    CSS_PROP_DOMPROP_PREFIXED(FontSmoothing),
+    CSS_PROPERTY_PARSE_VALUE |
+        CSS_PROPERTY_APPLIES_TO_FIRST_LETTER_AND_FIRST_LINE |
+        CSS_PROPERTY_APPLIES_TO_PLACEHOLDER,
+    "",
+    VARIANT_HK,
+    kFontSmoothingKTable,
+    CSS_PROP_NO_OFFSET,
+    eStyleAnimType_None)
 CSS_PROP_FONT(
     font-stretch,
     font_stretch,

layout/style/nsCSSProps.cpp

@@ -1042,6 +1042,12 @@ const int32_t nsCSSProps::kFontSizeKTable[] = {
   eCSSKeyword_UNKNOWN,-1
 };
 
+const int32_t nsCSSProps::kFontSmoothingKTable[] = {
+  eCSSKeyword_auto, NS_FONT_SMOOTHING_AUTO,
+  eCSSKeyword_antialiased, NS_FONT_SMOOTHING_ANTIALIASED,
+  eCSSKeyword_UNKNOWN,-1
+};
+
 const int32_t nsCSSProps::kFontStretchKTable[] = {
   eCSSKeyword_ultra_condensed, NS_STYLE_FONT_STRETCH_ULTRA_CONDENSED,
   eCSSKeyword_extra_condensed, NS_STYLE_FONT_STRETCH_EXTRA_CONDENSED,

layout/style/nsCSSProps.h

@@ -481,6 +481,7 @@ public:
   static const int32_t kFontKTable[];
   static const int32_t kFontKerningKTable[];
   static const int32_t kFontSizeKTable[];
+  static const int32_t kFontSmoothingKTable[];
   static const int32_t kFontStretchKTable[];
   static const int32_t kFontStyleKTable[];
   static const int32_t kFontSynthesisKTable[];

layout/style/nsComputedDOMStyle.cpp

@@ -1276,6 +1276,15 @@ nsComputedDOMStyle::DoGetFontSizeAdjust()
   return val;
 }
 
+CSSValue*
+nsComputedDOMStyle::DoGetFontSmoothing()
+{
+  nsROCSSPrimitiveValue* val = new nsROCSSPrimitiveValue;
+  val->SetIdent(nsCSSProps::ValueToKeywordEnum(StyleFont()->mFont.smoothing,
+                                               nsCSSProps::kFontSmoothingKTable));
+  return val;
+}
+
 CSSValue*
 nsComputedDOMStyle::DoGetFontStretch()
 {
@@ -5133,6 +5142,7 @@ nsComputedDOMStyle::GetQueryablePropertyMap(uint32_t* aLength)
     COMPUTED_STYLE_MAP_ENTRY(float_edge,                    FloatEdge),
     COMPUTED_STYLE_MAP_ENTRY(font_feature_settings,         FontFeatureSettings),
     COMPUTED_STYLE_MAP_ENTRY(font_language_override,        FontLanguageOverride),
+    COMPUTED_STYLE_MAP_ENTRY(font_smoothing,                FontSmoothing),
     COMPUTED_STYLE_MAP_ENTRY(force_broken_image_icon,       ForceBrokenImageIcon),
     COMPUTED_STYLE_MAP_ENTRY(hyphens,                       Hyphens),
     COMPUTED_STYLE_MAP_ENTRY(image_region,                  ImageRegion),

layout/style/nsComputedDOMStyle.h

@@ -194,6 +194,7 @@ private:
   mozilla::dom::CSSValue* DoGetFontLanguageOverride();
   mozilla::dom::CSSValue* DoGetFontSize();
   mozilla::dom::CSSValue* DoGetFontSizeAdjust();
+  mozilla::dom::CSSValue* DoGetFontSmoothing();
   mozilla::dom::CSSValue* DoGetFontStretch();
   mozilla::dom::CSSValue* DoGetFontStyle();
   mozilla::dom::CSSValue* DoGetFontSynthesis();

layout/style/nsRuleNode.cpp

@@ -3197,6 +3197,14 @@ nsRuleNode::SetFont(nsPresContext* aPresContext, nsStyleContext* aContext,
     aFont->mGenericID = aGenericFontID;
   }
 
+  // font-smoothing: enum, inherit, initial
+  SetDiscrete(*aRuleData->ValueForFontSmoothing(),
+              aFont->mFont.smoothing, aCanStoreInRuleTree,
+              SETDSC_ENUMERATED,
+              aParentFont->mFont.smoothing,
+              defaultVariableFont->smoothing,
+              0, 0, 0, 0);
+
   // font-style: enum, inherit, initial, -moz-system-font
   SetDiscrete(*aRuleData->ValueForFontStyle(),
               aFont->mFont.style, aCanStoreInRuleTree,

layout/style/nsStyleStruct.cpp

@@ -215,6 +215,7 @@ nsChangeHint nsStyleFont::CalcFontDifference(const nsFont& aFont1, const nsFont&
       (aFont1.variant == aFont2.variant) &&
       (aFont1.weight == aFont2.weight) &&
       (aFont1.stretch == aFont2.stretch) &&
+      (aFont1.smoothing == aFont2.smoothing) &&
       (aFont1.name == aFont2.name) &&
       (aFont1.kerning == aFont2.kerning) &&
       (aFont1.synthesis == aFont2.synthesis) &&

layout/style/test/property_database.js

@@ -2466,6 +2466,14 @@ var gCSSProperties = {
 		other_values: [ "0.3", "0.5", "0.7" ],
 		invalid_values: []
 	},
+	"-moz-font-smoothing": {
+		domProp: "MozFontSmoothing",
+		inherited: true,
+		type: CSS_TYPE_LONGHAND,
+		initial_values: [ "auto" ],
+		other_values: [ "antialiased" ],
+		invalid_values: [ "none", "subpixel-antialiased" ]
+	},
 	"font-stretch": {
 		domProp: "fontStretch",
 		inherited: true,