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     GrDistanceFieldTextContext(GrContext*, const SkDeviceProperties&, bool enable);
  22     virtual ~GrDistanceFieldTextContext();
  23
  24     virtual void drawText(const GrPaint&, const SkPaint&, const char text[], size_t byteLength,
  25                           SkScalar x, SkScalar y) SK_OVERRIDE;
  26     virtual void drawPosText(const GrPaint&, const SkPaint&,
  27                              const char text[], size_t byteLength,
  28                              const SkScalar pos[], SkScalar constY,
  29                              int scalarsPerPosition) SK_OVERRIDE;
  30
  31     virtual bool canDraw(const SkPaint& paint) SK_OVERRIDE;
  32
  33 private:
  34     GrTextStrike*                      fStrike;
  35     SkScalar                           fTextRatio;
  36     bool                               fUseLCDText;
  37     bool                               fEnableDFRendering;
  38     SkAutoTUnref<GrGeometryProcessor>  fCachedGeometryProcessor;
  39     // Used to check whether fCachedEffect is still valid.
  40     uint32_t                fEffectTextureUniqueID;
  41     SkColor                 fEffectColor;
  42     uint32_t                fEffectFlags;
  43     GrTexture*              fGammaTexture;
  44
  45     void init(const GrPaint&, const SkPaint&);
  46     void drawPackedGlyph(GrGlyph::PackedID, SkFixed left, SkFixed top, GrFontScaler*);
  47     void flushGlyphs();                 // automatically called by destructor
  48     void setupCoverageEffect(const SkColor& filteredColor);
  49     void finish();
  50
  51     enum {
  52         kMinRequestedGlyphs      = 1,
  53         kDefaultRequestedGlyphs  = 64,
  54         kMinRequestedVerts       = kMinRequestedGlyphs * 4,
  55         kDefaultRequestedVerts   = kDefaultRequestedGlyphs * 4,
  56     };
  57
  58     void*                   fVertices;
  59     int32_t                 fMaxVertices;
  60     GrTexture*              fCurrTexture;
  61     int                     fCurrVertex;
  62     SkRect                  fVertexBounds;
  63 };
  64
  65 #endif