SkDrawProcs.h revision 44fb865e81a57e0c72de3109d0ed5ea428aa1f44 
1
2/*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8#ifndef SkDrawProcs_DEFINED
9#define SkDrawProcs_DEFINED
10
11#include "SkBlitter.h"
12#include "SkDraw.h"
13
14class SkAAClip;
15class SkBlitter;
16
17struct SkDraw1Glyph {
18    const SkDraw* fDraw;
19    SkBounder* fBounder;
20    const SkRegion* fClip;
21    const SkAAClip* fAAClip;
22    SkBlitter* fBlitter;
23    SkGlyphCache* fCache;
24    const SkPaint* fPaint;
25    SkIRect fClipBounds;
26    /** Half the sampling frequency of the rasterized glyph in x. */
27    SkFixed fHalfSampleX;
28    /** Half the sampling frequency of the rasterized glyph in y. */
29    SkFixed fHalfSampleY;
30
31    /** Draws one glyph.
32     *
33     *  The x and y are pre-biased, so implementations may just truncate them.
34     *  i.e. half the sampling frequency has been added.
35     *  e.g. 1/2 or 1/(2^(SkGlyph::kSubBits+1)) has already been added.
36     *  This added bias can be found in fHalfSampleX,Y.
37     */
38    typedef void (*Proc)(const SkDraw1Glyph&, SkFixed x, SkFixed y, const SkGlyph&);
39
40    Proc init(const SkDraw* draw, SkBlitter* blitter, SkGlyphCache* cache,
41              const SkPaint&);
42
43    // call this instead of fBlitter->blitMask() since this wrapper will handle
44    // the case when the mask is ARGB32_Format
45    //
46    void blitMask(const SkMask& mask, const SkIRect& clip) const {
47        if (SkMask::kARGB32_Format == mask.fFormat) {
48            this->blitMaskAsSprite(mask);
49        } else {
50            fBlitter->blitMask(mask, clip);
51        }
52    }
53
54    // mask must be kARGB32_Format
55    void blitMaskAsSprite(const SkMask& mask) const;
56};
57
58struct SkDrawProcs {
59    SkDraw1Glyph::Proc  fD1GProc;
60};
61
62bool SkDrawTreatAAStrokeAsHairline(SkScalar strokeWidth, const SkMatrix&,
63                                   SkScalar* coverage);
64
65/**
66 *  If the current paint is set to stroke and the stroke-width when applied to
67 *  the matrix is <= 1.0, then this returns true, and sets coverage (simulating
68 *  a stroke by drawing a hairline with partial coverage). If any of these
69 *  conditions are false, then this returns false and coverage is ignored.
70 */
71inline bool SkDrawTreatAsHairline(const SkPaint& paint, const SkMatrix& matrix,
72                                  SkScalar* coverage) {
73    if (SkPaint::kStroke_Style != paint.getStyle()) {
74        return false;
75    }
76
77    SkScalar strokeWidth = paint.getStrokeWidth();
78    if (0 == strokeWidth) {
79        *coverage = SK_Scalar1;
80        return true;
81    }
82
83    if (!paint.isAntiAlias()) {
84        return false;
85    }
86
87    return SkDrawTreatAAStrokeAsHairline(strokeWidth, matrix, coverage);
88}
89
90#endif
91