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 "GrDrawState.h"
13#include "GrDrawTarget.h"
14#include "SkStrokeRec.h"
15
16class GrTextStrike;
17class GrPath;
18class GrPathRange;
19
20/*
21 * This class implements text rendering using stencil and cover path rendering
22 * (by the means of GrDrawTarget::drawPath).
23 * This class exposes the functionality through GrTextContext interface.
24 */
25class GrStencilAndCoverTextContext : public GrTextContext {
26public:
27    GrStencilAndCoverTextContext(GrContext*, const SkDeviceProperties&);
28    virtual ~GrStencilAndCoverTextContext();
29
30    virtual void drawText(const GrPaint&, const SkPaint&, const char text[],
31                          size_t byteLength,
32                          SkScalar x, SkScalar y) SK_OVERRIDE;
33    virtual void drawPosText(const GrPaint&, const SkPaint&,
34                             const char text[], size_t byteLength,
35                             const SkScalar pos[], SkScalar constY,
36                             int scalarsPerPosition) SK_OVERRIDE;
37
38    virtual bool canDraw(const SkPaint& paint) SK_OVERRIDE;
39
40private:
41    static const int kGlyphBufferSize = 1024;
42
43    enum RenderMode {
44        /**
45         * This is the render mode used by drawText(), which is mainly used by
46         * the Skia unit tests. It tries match the other text backends exactly,
47         * with the exception of not implementing LCD text, and doing anti-
48         * aliasing with the built-in MSAA.
49         */
50        kMaxAccuracy_RenderMode,
51
52        /**
53         * This is the render mode used by drawPosText(). It ignores hinting and
54         * LCD text, even if the client provided positions for hinted glyphs,
55         * and renders from a canonically-sized, generic set of paths for the
56         * given typeface. In the future we should work out a system for the
57         * client to know it should not provide hinted glyph positions. This
58         * render mode also tries to use GPU stroking for fake bold, even when
59         * SK_USE_FREETYPE_EMBOLDEN is set.
60         */
61        kMaxPerformance_RenderMode,
62    };
63
64    void init(const GrPaint&, const SkPaint&, size_t textByteLength,
65              RenderMode, SkScalar textTranslateY = 0);
66    void initGlyphs(SkGlyphCache* cache);
67    void appendGlyph(uint16_t glyphID, float x);
68    void appendGlyph(uint16_t glyphID, float x, float y);
69    void flush();
70    void finish();
71
72    GrDrawState::AutoRestoreEffects fStateRestore;
73    SkScalar fTextRatio;
74    float fTextInverseRatio;
75    SkGlyphCache* fGlyphCache;
76    GrPathRange* fGlyphs;
77    uint32_t fIndexBuffer[kGlyphBufferSize];
78    float fTransformBuffer[2 * kGlyphBufferSize];
79    GrDrawTarget::PathTransformType fTransformType;
80    int fPendingGlyphCount;
81    SkMatrix fContextInitialMatrix;
82    bool fNeedsDeviceSpaceGlyphs;
83};
84
85#endif
86