Bug 2071557 - Keep color-font palette entries as hb_color_t to reduce memory footprint. r=firefox-style-system-reviewers,emilio

Differential Revision: https://phabricator.services.mozilla.com/D325607

gfx/tests/fuzz/TestCOLRv1.cpp

@@ -43,7 +43,7 @@ static int FuzzingRunCOLRv1(const uint8_t* data, size_t size) {
   Float f2p = kPixelSize / hb_face_get_upem(hb_data_face);
 
   auto colorPalette =
-      MakeUnique<nsTArray<sRGBColor>>(COLRFonts::CreateColorPalette(
+      MakeUnique<nsTArray<hb_color_t>>(COLRFonts::CreateColorPalette(
           hb_data_face, nullptr, nullptr, "dummy"_ns));
 
   for (unsigned i = 0; i <= glyph_count; ++i) {

gfx/thebes/COLRFonts.cpp

@@ -11,7 +11,6 @@
 #include "gfxFontUtils.h"
 #include "gfxUtils.h"
 #include "harfbuzz/hb-ot.h"
-#include "harfbuzz/hb.h"
 #include "mozilla/ScopeExit.h"
 #include "mozilla/StaticPrefs_gfx.h"
 #include "mozilla/gfx/Helpers.h"
@@ -147,7 +146,7 @@ struct PaintState {
     const COLRHeader* v0;
     const COLRv1Header* v1;
   } mHeader;
-  const sRGBColor* mPalette;
+  const hb_color_t* mPalette;
   DrawTarget* mDrawTarget;
   ScaledFont* mScaledFont;
   const int* mCoords;
@@ -177,7 +176,11 @@ constexpr uint32_t kPaintRecursionLimit = 256;
 DeviceColor PaintState::GetColor(uint16_t aPaletteIndex, float aAlpha) const {
   sRGBColor color;
   if (aPaletteIndex < mNumColors) {
-    color = mPalette[uint16_t(aPaletteIndex)];
+    hb_color_t c = mPalette[uint16_t(aPaletteIndex)];
+    // Explicitly get the components from the hb_color_t, rather than assuming
+    // anything about its packing.
+    color = sRGBColor::FromU8(hb_color_get_red(c), hb_color_get_green(c),
+                              hb_color_get_blue(c), hb_color_get_alpha(c));
   } else if (aPaletteIndex == 0xffff) {
     color = mCurrentColor;
   } else {  // Palette index out of range! Return transparent black.
@@ -2464,7 +2467,7 @@ bool COLRFonts::PaintGlyphLayers(
     hb_blob_t* aCOLR, hb_face_t* aFace, const GlyphLayers* aLayers,
     DrawTarget* aDrawTarget, layout::TextDrawTarget* aTextDrawer,
     ScaledFont* aScaledFont, DrawOptions aDrawOptions, const Point& aPoint,
-    const sRGBColor& aCurrentColor, const nsTArray<sRGBColor>* aColors) {
+    const sRGBColor& aCurrentColor, const nsTArray<hb_color_t>* aColors) {
   const auto* glyphRecord = reinterpret_cast<const BaseGlyphRecord*>(aLayers);
   // Default to opaque rendering (non-webrender applies alpha with a layer)
   float alpha = 1.0;
@@ -2530,7 +2533,7 @@ bool COLRFonts::PaintGlyphGraph(
     hb_blob_t* aCOLR, hb_font_t* aFont, const GlyphPaintGraph* aPaintGraph,
     DrawTarget* aDrawTarget, layout::TextDrawTarget* aTextDrawer,
     ScaledFont* aScaledFont, DrawOptions aDrawOptions, const Point& aPoint,
-    const sRGBColor& aCurrentColor, const nsTArray<sRGBColor>* aColors,
+    const sRGBColor& aCurrentColor, const nsTArray<hb_color_t>* aColors,
     uint32_t aGlyphId, float aFontUnitsToPixels) {
   if (aTextDrawer) {
     // Currently we always punt to a blob for COLRv1 glyphs.
@@ -2612,7 +2615,7 @@ uint16_t COLRFonts::GetColrTableVersion(hb_blob_t* aCOLR) {
   return colr->version;
 }
 
-nsTArray<sRGBColor> COLRFonts::CreateColorPalette(
+nsTArray<hb_color_t> COLRFonts::CreateColorPalette(
     hb_face_t* aFace, const FontPaletteValueSet* aPaletteValueSet,
     nsAtom* aFontPalette, const nsACString& aFamilyName) {
   // Find the base color palette to use, if there are multiple available;
@@ -2659,27 +2662,24 @@ nsTArray<sRGBColor> COLRFonts::CreateColorPalette(
     }
   }
 
-  // Collect the palette colors and convert them to sRGBColor values.
+  // Collect the palette colors.
   count =
       hb_ot_color_palette_get_colors(aFace, paletteIndex, 0, nullptr, nullptr);
-  nsTArray<hb_color_t> colors;
-  colors.SetLength(count);
+  nsTArray<hb_color_t> palette;
+  palette.SetLength(count);
   hb_ot_color_palette_get_colors(aFace, paletteIndex, 0, &count,
-                                 colors.Elements());
-
-  nsTArray<sRGBColor> palette;
-  palette.SetCapacity(count);
-  for (const auto c : colors) {
-    palette.AppendElement(
-        sRGBColor(hb_color_get_red(c) / 255.0, hb_color_get_green(c) / 255.0,
-                  hb_color_get_blue(c) / 255.0, hb_color_get_alpha(c) / 255.0));
-  }
+                                 palette.Elements());
 
   // Apply @font-palette-values overrides, if present.
   if (fpv) {
     for (const auto overrideColor : fpv->mOverrides) {
       if (overrideColor.mIndex < palette.Length()) {
-        palette[overrideColor.mIndex] = overrideColor.mColor;
+        // Override colors contain nscolor, but the palette uses hb_color_t.
+        // They have different byte packing orders, so we have to explicitly
+        // map the components, not just assign as a 32-bit value.
+        nscolor c = overrideColor.mColor;
+        palette[overrideColor.mIndex] =
+            HB_COLOR(NS_GET_B(c), NS_GET_G(c), NS_GET_R(c), NS_GET_A(c));
       }
     }
   }

gfx/thebes/COLRFonts.h

@@ -5,15 +5,13 @@
 #ifndef COLR_FONTS_H
 #define COLR_FONTS_H
 
+#include "harfbuzz/hb.h"
 #include "mozilla/gfx/2D.h"
 #include "nsAtom.h"
+#include "nsColor.h"
 #include "nsTArray.h"
 #include "nsTHashtable.h"
 
-struct hb_blob_t;
-struct hb_face_t;
-struct hb_font_t;
-
 namespace mozilla {
 
 namespace layout {
@@ -28,7 +26,7 @@ class FontPaletteValueSet {
 
   struct OverrideColor {
     uint32_t mIndex = 0;
-    sRGBColor mColor;
+    nscolor mColor;
   };
 
   struct PaletteValues {
@@ -100,7 +98,7 @@ class COLRFonts {
       hb_blob_t* aCOLR, hb_face_t* aFace, const GlyphLayers* aLayers,
       DrawTarget* aDrawTarget, layout::TextDrawTarget* aTextDrawer,
       ScaledFont* aScaledFont, DrawOptions aDrawOptions, const Point& aPoint,
-      const sRGBColor& aCurrentColor, const nsTArray<sRGBColor>* aColors);
+      const sRGBColor& aCurrentColor, const nsTArray<hb_color_t>* aColors);
 
   // COLRv1 support: color glyph is represented by a directed acyclic graph of
   // paint records.
@@ -114,7 +112,7 @@ class COLRFonts {
       hb_blob_t* aCOLR, hb_font_t* aFont, const GlyphPaintGraph* aPaintGraph,
       DrawTarget* aDrawTarget, layout::TextDrawTarget* aTextDrawer,
       ScaledFont* aScaledFont, DrawOptions aDrawOptions, const Point& aPoint,
-      const sRGBColor& aCurrentColor, const nsTArray<sRGBColor>* aColors,
+      const sRGBColor& aCurrentColor, const nsTArray<hb_color_t>* aColors,
       uint32_t aGlyphId, float aFontUnitsToPixels);
 
   static Rect GetColorGlyphBounds(hb_blob_t* aCOLR, hb_font_t* aFont,
@@ -124,7 +122,7 @@ class COLRFonts {
 
   static uint16_t GetColrTableVersion(hb_blob_t* aCOLR);
 
-  static nsTArray<sRGBColor> CreateColorPalette(
+  static nsTArray<hb_color_t> CreateColorPalette(
       hb_face_t* aFace, const FontPaletteValueSet* aPaletteValueSet,
       nsAtom* aFontPalette, const nsACString& aFamilyName);
 };

gfx/thebes/FontPaletteCache.h

@@ -7,6 +7,7 @@
 
 #include <utility>
 
+#include "harfbuzz/hb.h"
 #include "mozilla/HashFunctions.h"
 #include "mozilla/MruCache.h"
 #include "mozilla/RefPtr.h"
@@ -26,15 +27,15 @@ class FontPalette {
 
  public:
   FontPalette() = default;
-  explicit FontPalette(nsTArray<mozilla::gfx::sRGBColor>&& aColors)
+  explicit FontPalette(nsTArray<hb_color_t>&& aColors)
       : mColors(std::move(aColors)) {}
 
-  const nsTArray<mozilla::gfx::sRGBColor>* Colors() const { return &mColors; }
+  const nsTArray<hb_color_t>* Colors() const { return &mColors; }
 
  private:
   ~FontPalette() = default;
 
-  nsTArray<mozilla::gfx::sRGBColor> mColors;
+  nsTArray<hb_color_t> mColors;
 };
 
 // MRU cache used for resolved color-font palettes, to avoid reconstructing

layout/style/GeckoBindings.cpp

@@ -1030,7 +1030,7 @@ void Gecko_SetFontPaletteOverride(
     return;
   }
   aValues->mOverrides.AppendElement(gfx::FontPaletteValueSet::OverrideColor{
-      uint32_t(aIndex), gfx::sRGBColor::FromABGR(aColor->ToColor())});
+      uint32_t(aIndex), aColor->ToColor()});
 }
 
 void Gecko_EnsureImageLayersLength(nsStyleImageLayers* aLayers, size_t aLen,