src/gpu/GrStencilAndCoverTextContext.h

   1 /*
   2  * Copyright 2014 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 GrStencilAndCoverTextContext_DEFINED
   9 #define GrStencilAndCoverTextContext_DEFINED
  10
  11 #include "GrTextContext.h"
  12 #include "GrDrawTarget.h"
  13 #include "SkStrokeRec.h"
  14
  15 class GrTextStrike;
  16 class GrPath;
  17 class GrPathRange;
  18
  19 /*
  20  * This class implements text rendering using stencil and cover path rendering
  21  * (by the means of GrDrawTarget::drawPath).
  22  * This class exposes the functionality through GrTextContext interface.
  23  */
  24 class GrStencilAndCoverTextContext : public GrTextContext {
  25 public:
  26     static GrStencilAndCoverTextContext* Create(GrContext*, SkGpuDevice*,
  27                                                 const SkDeviceProperties&);
  28
  29     virtual ~GrStencilAndCoverTextContext();
  30
  31 private:
  32     static const int kGlyphBufferSize = 1024;
  33
  34     enum RenderMode {
  35         /**
  36          * This is the render mode used by drawText(), which is mainly used by
  37          * the Skia unit tests. It tries match the other text backends exactly,
  38          * with the exception of not implementing LCD text, and doing anti-
  39          * aliasing with the built-in MSAA.
  40          */
  41         kMaxAccuracy_RenderMode,
  42
  43         /**
  44          * This is the render mode used by drawPosText(). It ignores hinting and
  45          * LCD text, even if the client provided positions for hinted glyphs,
  46          * and renders from a canonically-sized, generic set of paths for the
  47          * given typeface. In the future we should work out a system for the
  48          * client to know it should not provide hinted glyph positions. This
  49          * render mode also tries to use GPU stroking for fake bold, even when
  50          * SK_USE_FREETYPE_EMBOLDEN is set.
  51          */
  52         kMaxPerformance_RenderMode,
  53     };
  54
  55     GrPipelineBuilder                                   fPipelineBuilder;
  56     GrPipelineBuilder::AutoRestoreFragmentProcessors    fStateRestore;
  57     SkScalar                                            fTextRatio;
  58     float                                               fTextInverseRatio;
  59     SkGlyphCache*                                       fGlyphCache;
  60     GrPathRange*                                        fGlyphs;
  61     SkStrokeRec                                         fStroke;
  62     uint16_t                                            fGlyphIndices[kGlyphBufferSize];
  63     SkPoint                                             fGlyphPositions[kGlyphBufferSize];
  64     int                                                 fQueuedGlyphCount;
  65     int                                                 fFallbackGlyphsIdx;
  66     SkMatrix                                            fContextInitialMatrix;
  67     SkMatrix                                            fViewMatrix;
  68     SkMatrix                                            fLocalMatrix;
  69     bool                                                fUsingDeviceSpaceGlyphs;
  70
  71     GrStencilAndCoverTextContext(GrContext*, SkGpuDevice*, const SkDeviceProperties&);
  72
  73     bool canDraw(const GrRenderTarget*, const GrClip&, const GrPaint&,
  74                  const SkPaint&, const SkMatrix& viewMatrix) SK_OVERRIDE;
  75
  76     void onDrawText(GrRenderTarget*, const GrClip&, const GrPaint&, const SkPaint&,
  77                     const SkMatrix& viewMatrix,
  78                     const char text[], size_t byteLength,
  79                     SkScalar x, SkScalar y, const SkIRect& regionClipBounds) SK_OVERRIDE;
  80     void onDrawPosText(GrRenderTarget*, const GrClip&, const GrPaint&, const SkPaint&,
  81                        const SkMatrix& viewMatrix,
  82                        const char text[], size_t byteLength,
  83                        const SkScalar pos[], int scalarsPerPosition,
  84                        const SkPoint& offset, const SkIRect& regionClipBounds) SK_OVERRIDE;
  85
  86     void init(GrRenderTarget*, const GrClip&, const GrPaint&, const SkPaint&,
  87               size_t textByteLength, RenderMode, const SkMatrix& viewMatrix,
  88               const SkIRect& regionClipBounds);
  89     bool mapToFallbackContext(SkMatrix* inverse);
  90     void appendGlyph(const SkGlyph&, const SkPoint&);
  91     void flush();
  92     void finish();
  93
  94 };
  95
  96 #endif