src/third_party/skia/src/gpu/GrDistanceFieldTextContext.h

   1 /*
   2  * Copyright 2013 Google Inc.
   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 GrDistanceFieldTextContext_DEFINED
   9 #define GrDistanceFieldTextContext_DEFINED
  10
  11 #include "GrTextContext.h"
  12
  13 class GrGeometryProcessor;
  14 class GrTextStrike;
  15
  16 /*
  17  * This class implements GrTextContext using distance field fonts
  18  */
  19 class GrDistanceFieldTextContext : public GrTextContext {
  20 public:
  21     static GrDistanceFieldTextContext* Create(GrContext*, const SkDeviceProperties&, bool enable);
  22
  23     virtual ~GrDistanceFieldTextContext();
  24
  25 private:
  26     enum {
  27         kMinRequestedGlyphs      = 1,
  28         kDefaultRequestedGlyphs  = 64,
  29         kMinRequestedVerts       = kMinRequestedGlyphs * 4,
  30         kDefaultRequestedVerts   = kDefaultRequestedGlyphs * 4,
  31     };
  32
  33     GrTextStrike*                      fStrike;
  34     SkScalar                           fTextRatio;
  35     bool                               fUseLCDText;
  36     bool                               fEnableDFRendering;
  37     SkAutoTUnref<GrGeometryProcessor>  fCachedGeometryProcessor;
  38     // Used to check whether fCachedEffect is still valid.
  39     uint32_t                           fEffectTextureUniqueID;
  40     SkColor                            fEffectColor;
  41     uint32_t                           fEffectFlags;
  42     GrTexture*                         fGammaTexture;
  43     void*                              fVertices;
  44     int                                fCurrVertex;
  45     int                                fAllocVertexCount;
  46     int                                fTotalVertexCount;
  47     GrTexture*                         fCurrTexture;
  48     SkRect                             fVertexBounds;
  49
  50     GrDistanceFieldTextContext(GrContext*, const SkDeviceProperties&, bool enable);
  51
  52     virtual bool canDraw(const SkPaint& paint) SK_OVERRIDE;
  53
  54     virtual void onDrawText(const GrPaint&, const SkPaint&, const char text[], size_t byteLength,
  55                             SkScalar x, SkScalar y) SK_OVERRIDE;
  56     virtual void onDrawPosText(const GrPaint&, const SkPaint&,
  57                                const char text[], size_t byteLength,
  58                                const SkScalar pos[], int scalarsPerPosition,
  59                                const SkPoint& offset) SK_OVERRIDE;
  60
  61     void init(const GrPaint&, const SkPaint&);
  62     bool appendGlyph(GrGlyph::PackedID, SkScalar left, SkScalar top, GrFontScaler*);
  63     void setupCoverageEffect(const SkColor& filteredColor);
  64     void flush();                 // automatically called by destructor
  65     void finish();
  66 };
  67
  68 #endif