Bug 1461589 - Handle font-variant-emoji during font matching. r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D147495

dom/canvas/CanvasRenderingContext2D.cpp

@@ -3526,15 +3526,16 @@ bool CanvasRenderingContext2D::SetFontInternalDisconnected(
   // TODO: For workers, should we be passing a language? Where from?
 
   // TODO: Cache fontGroups in the Worker (use an nsFontCache?)
-  gfxFontGroup* fontGroup = gfxPlatform::GetPlatform()->CreateFontGroup(
-      nullptr,           // aPresContext
-      list,              // aFontFamilyList
-      &fontStyle,        // aStyle
-      language,          // aLanguage
-      explicitLanguage,  // aExplicitLanguage
-      nullptr,           // aTextPerf
-      fontFaceSetImpl,   // aUserFontSet
-      1.0);              // aDevToCssSize
+  gfxFontGroup* fontGroup =
+      new gfxFontGroup(nullptr,           // aPresContext
+                       list,              // aFontFamilyList
+                       &fontStyle,        // aStyle
+                       language,          // aLanguage
+                       explicitLanguage,  // aExplicitLanguage
+                       nullptr,           // aTextPerf
+                       fontFaceSetImpl,   // aUserFontSet
+                       1.0,               // aDevToCssSize
+                       StyleFontVariantEmoji::Normal);
   CurrentState().fontGroup = fontGroup;
   SerializeFontForCanvas(list, fontStyle, CurrentState().font);
   CurrentState().fontFont = nsFont(StyleFontFamily{list, false, false},
@@ -4327,10 +4328,10 @@ gfxFontGroup* CanvasRenderingContext2D::GetCurrentFontStyle() {
       gfxFloat devToCssSize = gfxFloat(perDevPixel) / gfxFloat(perCSSPixel);
       const auto* sans =
           Servo_FontFamily_Generic(StyleGenericFontFamily::SansSerif);
-      fontGroup = gfxPlatform::GetPlatform()->CreateFontGroup(
+      fontGroup = new gfxFontGroup(
           presContext, sans->families, &style, language, explicitLanguage,
           presContext ? presContext->GetTextPerfMetrics() : nullptr, nullptr,
-          devToCssSize);
+          devToCssSize, StyleFontVariantEmoji::Normal);
       if (fontGroup) {
         CurrentState().font = kDefaultFontStyle;
       } else {

gfx/src/nsFontMetrics.cpp

@@ -138,9 +138,9 @@ nsFontMetrics::nsFontMetrics(const nsFont& aFont, const Params& aParams,
   aFont.AddFontVariationsToStyle(&style);
 
   gfxFloat devToCssSize = gfxFloat(mP2A) / gfxFloat(AppUnitsPerCSSPixel());
-  mFontGroup = gfxPlatform::GetPlatform()->CreateFontGroup(
+  mFontGroup = new gfxFontGroup(
       mPresContext, aFont.family.families, &style, mLanguage, mExplicitLanguage,
-      aParams.textPerf, aParams.userFontSet, devToCssSize);
+      aParams.textPerf, aParams.userFontSet, devToCssSize, aFont.variantEmoji);
 }
 
 nsFontMetrics::~nsFontMetrics() {

gfx/thebes/gfxPlatform.cpp

@@ -1846,16 +1846,6 @@ bool gfxPlatform::IsFontFormatSupported(
   return true;
 }
 
-gfxFontGroup* gfxPlatform::CreateFontGroup(
-    nsPresContext* aPresContext, const StyleFontFamilyList& aFontFamilyList,
-    const gfxFontStyle* aStyle, nsAtom* aLanguage, bool aExplicitLanguage,
-    gfxTextPerfMetrics* aTextPerf, gfxUserFontSet* aUserFontSet,
-    gfxFloat aDevToCssSize) const {
-  return new gfxFontGroup(aPresContext, aFontFamilyList, aStyle, aLanguage,
-                          aExplicitLanguage, aTextPerf, aUserFontSet,
-                          aDevToCssSize);
-}
-
 gfxFontEntry* gfxPlatform::LookupLocalFont(nsPresContext* aPresContext,
                                            const nsACString& aFontName,
                                            WeightRange aWeightForEntry,

gfx/thebes/gfxPlatform.h

@@ -398,16 +398,6 @@ class gfxPlatform : public mozilla::layers::MemoryPressureListener {
   nsAutoCString GetDefaultFontName(const nsACString& aLangGroup,
                                    const nsACString& aGenericFamily);
 
-  /**
-   * Create a gfxFontGroup based on the given family list and style.
-   */
-  gfxFontGroup* CreateFontGroup(
-      nsPresContext* aPresContext,
-      const mozilla::StyleFontFamilyList& aFontFamilyList,
-      const gfxFontStyle* aStyle, nsAtom* aLanguage, bool aExplicitLanguage,
-      gfxTextPerfMetrics* aTextPerf, gfxUserFontSet* aUserFontSet,
-      gfxFloat aDevToCssSize) const;
-
   /**
    * Look up a local platform font using the full font face name.
    * (Needed to support @font-face src local().)

gfx/thebes/gfxTextRun.cpp

@@ -1884,7 +1884,8 @@ gfxFontGroup::gfxFontGroup(nsPresContext* aPresContext,
                            const gfxFontStyle* aStyle, nsAtom* aLanguage,
                            bool aExplicitLanguage,
                            gfxTextPerfMetrics* aTextPerf,
-                           gfxUserFontSet* aUserFontSet, gfxFloat aDevToCssSize)
+                           gfxUserFontSet* aUserFontSet, gfxFloat aDevToCssSize,
+                           StyleFontVariantEmoji aVariantEmoji)
     : mPresContext(aPresContext),  // Note that aPresContext may be null!
       mFamilyList(aFontFamilyList),
       mStyle(*aStyle),
@@ -1899,6 +1900,17 @@ gfxFontGroup::gfxFontGroup(nsPresContext* aPresContext,
       mLastPrefFirstFont(false),
       mSkipDrawing(false),
       mExplicitLanguage(aExplicitLanguage) {
+  switch (aVariantEmoji) {
+    case StyleFontVariantEmoji::Normal:
+    case StyleFontVariantEmoji::Unicode:
+      break;
+    case StyleFontVariantEmoji::Text:
+      mEmojiPresentation = eFontPresentation::Text;
+      break;
+    case StyleFontVariantEmoji::Emoji:
+      mEmojiPresentation = eFontPresentation::EmojiExplicit;
+      break;
+  }
   // We don't use SetUserFontSet() here, as we want to unconditionally call
   // BuildFontList() rather than only do UpdateUserFonts() if it changed.
   mCurrGeneration = GetGeneration();
@@ -3100,24 +3112,27 @@ already_AddRefed<gfxFont> gfxFontGroup::FindFontForChar(
   eFontPresentation presentation = eFontPresentation::Any;
   EmojiPresentation emojiPresentation = GetEmojiPresentation(aCh);
   if (emojiPresentation != TextOnly) {
-    // If the prefer-emoji selector is present, or if it's a default-emoji char
-    // and the prefer-text selector is NOT present, or if there's a skin-tone
-    // modifier, we specifically look for a font with a color glyph.
-    // If the prefer-text selector is present, we specifically look for a font
-    // that will provide a monochrome glyph.
-    // Otherwise, we'll accept either color or monochrome font-family entries,
-    // so that a color font can be explicitly applied via font-family even to
-    // characters that are not inherently emoji-style.
+    // Default presentation from the font-variant-emoji property.
+    presentation = mEmojiPresentation;
+    // If the prefer-emoji selector is present, or if it's a default-emoji
+    // char and the prefer-text selector is NOT present, or if there's a
+    // skin-tone modifier, we specifically look for a font with a color
+    // glyph.
+    // If the prefer-text selector is present, we specifically look for a
+    // font that will provide a monochrome glyph.
+    // Otherwise, we'll accept either color or monochrome font-family
+    // entries, so that a color font can be explicitly applied via font-
+    // family even to characters that are not inherently emoji-style.
     if (aNextCh == kVariationSelector16 ||
         (aNextCh >= kEmojiSkinToneFirst && aNextCh <= kEmojiSkinToneLast)) {
-      // Emoji presentation is explicitly requested by a variation selector or
-      // the presence of a skin-tone codepoint.
+      // Emoji presentation is explicitly requested by a variation selector
+      // or the presence of a skin-tone codepoint.
       presentation = eFontPresentation::EmojiExplicit;
     } else if (emojiPresentation == EmojiPresentation::EmojiDefault &&
                aNextCh != kVariationSelector15) {
       // Emoji presentation is the default for this Unicode character. but we
-      // will allow an explicitly-specified webfont to apply to it, regardless
-      // of its glyph type.
+      // will allow an explicitly-specified webfont to apply to it,
+      // regardless of its glyph type.
       presentation = eFontPresentation::EmojiDefault;
     } else if (aNextCh == kVariationSelector15) {
       // Text presentation is explicitly requested.

gfx/thebes/gfxTextRun.h

@@ -936,7 +936,8 @@ class gfxFontGroup final : public gfxTextRunFactory {
                const mozilla::StyleFontFamilyList& aFontFamilyList,
                const gfxFontStyle* aStyle, nsAtom* aLanguage,
                bool aExplicitLanguage, gfxTextPerfMetrics* aTextPerf,
-               gfxUserFontSet* aUserFontSet, gfxFloat aDevToCssSize);
+               gfxUserFontSet* aUserFontSet, gfxFloat aDevToCssSize,
+               StyleFontVariantEmoji aVariantEmoji);
 
   virtual ~gfxFontGroup();
 
@@ -1420,6 +1421,8 @@ class gfxFontGroup final : public gfxTextRunFactory {
 
   bool mExplicitLanguage;  // Does mLanguage come from an explicit attribute?
 
+  eFontPresentation mEmojiPresentation = eFontPresentation::Any;
+
   // Generic font family used to select among font prefs during fallback.
   mozilla::StyleGenericFontFamily mFallbackGeneric =
       mozilla::StyleGenericFontFamily::None;