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) 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) 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) 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
97