gfx/thebes/FontPaletteCache.h

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef FONT_PALETTE_CACHE_H
   7 #define FONT_PALETTE_CACHE_H
   8
   9 #include "mozilla/gfx/Types.h"
  10 #include "mozilla/MruCache.h"
  11 #include "mozilla/HashFunctions.h"
  12 #include "mozilla/RefPtr.h"
  13 #include "nsAtom.h"
  14 #include "nsTArray.h"
  15 #include <utility>
  16
  17 class gfxFontEntry;
  18
  19 namespace mozilla::gfx {
  20
  21 class FontPaletteValueSet;
  22
  23 // A resolved font palette as an array of colors.
  24 class FontPalette {
  25   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(FontPalette);
  26
  27  public:
  28   FontPalette() = default;
  29   explicit FontPalette(nsTArray<mozilla::gfx::sRGBColor>&& aColors)
  30       : mColors(std::move(aColors)) {}
  31
  32   const nsTArray<mozilla::gfx::sRGBColor>* Colors() const { return &mColors; }
  33
  34  private:
  35   ~FontPalette() = default;
  36
  37   nsTArray<mozilla::gfx::sRGBColor> mColors;
  38 };
  39
  40 // MRU cache used for resolved color-font palettes, to avoid reconstructing
  41 // the palette for each glyph rendered with a given font.
  42 using CacheKey = std::pair<RefPtr<gfxFontEntry>, RefPtr<nsAtom>>;
  43 struct CacheData {
  44   CacheKey mKey;
  45   RefPtr<FontPalette> mPalette;
  46 };
  47
  48 class PaletteCache
  49     : public mozilla::MruCache<CacheKey, CacheData, PaletteCache> {
  50  public:
  51   explicit PaletteCache(const FontPaletteValueSet* aPaletteValueSet = nullptr)
  52       : mPaletteValueSet(aPaletteValueSet) {}
  53
  54   void SetPaletteValueSet(const FontPaletteValueSet* aSet);
  55
  56   already_AddRefed<FontPalette> GetPaletteFor(gfxFontEntry* aFontEntry,
  57                                               nsAtom* aPaletteName);
  58
  59   static mozilla::HashNumber Hash(const CacheKey& aKey) {
  60     return mozilla::HashGeneric(aKey.first.get(), aKey.second.get());
  61   }
  62   static bool Match(const CacheKey& aKey, const CacheData& aVal) {
  63     return aVal.mKey == aKey;
  64   }
  65
  66  protected:
  67   const FontPaletteValueSet* mPaletteValueSet = nullptr;
  68 };
  69
  70 }  // namespace mozilla::gfx
  71
  72 #endif