submodule/skia/src/text/gpu/GlyphVector.h

   1 /*
   2  * Copyright 2022 Google LLC
   3  *
   4  * Use of this source code is governed by a BSD-style license that can be
   5  * found in the LICENSE file.
   6  */
   7
   8 #ifndef sktext_gpu_GlyphVector_DEFINED
   9 #define sktext_gpu_GlyphVector_DEFINED
  10
  11 #include "include/core/SkSpan.h"
  12 #include "src/core/SkGlyph.h"
  13 #include "src/core/SkGlyphBuffer.h"
  14 #include "src/gpu/AtlasTypes.h"
  15 #include "src/text/gpu/Glyph.h"
  16 #include "src/text/gpu/StrikeCache.h"
  17 #include "src/text/gpu/SubRunAllocator.h"
  18
  19 class SkStrikeClient;
  20 #if SK_SUPPORT_GPU
  21 class GrMeshDrawTarget;
  22 #endif
  23
  24 namespace sktext::gpu {
  25
  26 // -- GlyphVector ----------------------------------------------------------------------------------
  27 // GlyphVector provides a way to delay the lookup of Glyphs until the code is running on the GPU
  28 // in single threaded mode. The GlyphVector is created in a multi-threaded environment, but the
  29 // StrikeCache is only single threaded (and must be single threaded because of the atlas).
  30 class GlyphVector {
  31 public:
  32     union Variant {
  33         // Initially, filled with packed id, but changed to Glyph* in the onPrepare stage.
  34         SkPackedGlyphID packedGlyphID;
  35         Glyph* glyph;
  36         // Add ctors to help SkArenaAlloc create arrays.
  37         Variant() : glyph{nullptr} {}
  38         Variant(SkPackedGlyphID id) : packedGlyphID{id} {}
  39     };
  40
  41     GlyphVector(sk_sp<SkStrike>&& strike, SkSpan<Variant> glyphs);
  42
  43     static GlyphVector Make(
  44             sk_sp<SkStrike>&& strike, SkSpan<SkGlyphVariant> glyphs, SubRunAllocator* alloc);
  45     SkSpan<const Glyph*> glyphs() const;
  46
  47     static std::optional<GlyphVector> MakeFromBuffer(SkReadBuffer& buffer,
  48                                                      const SkStrikeClient* strikeClient,
  49                                                      SubRunAllocator* alloc);
  50     void flatten(SkWriteBuffer& buffer);
  51
  52     // This doesn't need to include sizeof(GlyphVector) because this is embedded in each of
  53     // the sub runs.
  54     int unflattenSize() const { return GlyphVectorSize(fGlyphs.size()); }
  55
  56     void packedGlyphIDToGlyph(StrikeCache* cache);
  57
  58 #if SK_SUPPORT_GPU
  59     std::tuple<bool, int> regenerateAtlas(
  60             int begin, int end,
  61             skgpu::MaskFormat maskFormat,
  62             int srcPadding,
  63             GrMeshDrawTarget*);
  64 #endif
  65
  66     static size_t GlyphVectorSize(size_t count) {
  67         return sizeof(Variant) * count;
  68     }
  69
  70 private:
  71     friend class TestingPeer;
  72     sk_sp<SkStrike> fSkStrike;
  73     SkSpan<Variant> fGlyphs;
  74     sk_sp<TextStrike> fTextStrike{nullptr};
  75     uint64_t fAtlasGeneration{skgpu::AtlasGenerationCounter::kInvalidGeneration};
  76     skgpu::BulkUsePlotUpdater fBulkUseUpdater;
  77 };
  78
  79 }  // namespace sktext::gpu
  80
  81 #endif  // sktext_gpu_GlyphVector_DEFINED