1 /*
2 * Copyright 2011 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 SkDrawProcs_DEFINED
9 #define SkDrawProcs_DEFINED
10
11 #include "SkBlitter.h"
12 #include "SkDraw.h"
13 #include "SkGlyph.h"
14
15 class SkAAClip;
16 class SkBlitter;
17
18 struct SkDraw1Glyph {
19 const SkDraw* fDraw;
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 SkScalar fHalfSampleX;
28 /** Half the sampling frequency of the rasterized glyph in y. */
29 SkScalar 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&, Sk48Dot16 x, Sk48Dot16 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 //
blitMaskSkDraw1Glyph46 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
58 struct SkDrawProcs {
59 SkDraw1Glyph::Proc fD1GProc;
60 };
61
62 bool 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 */
SkDrawTreatAsHairline(const SkPaint & paint,const SkMatrix & matrix,SkScalar * coverage)71 inline 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 class SkTextAlignProc {
91 public:
SkTextAlignProc(SkPaint::Align align)92 SkTextAlignProc(SkPaint::Align align)
93 : fAlign(align) {
94 }
95
96 // Returns the glyph position, which may be rounded or not by the caller
97 // e.g. subpixel doesn't round.
operator()98 void operator()(const SkPoint& loc, const SkGlyph& glyph, SkPoint* dst) {
99 if (SkPaint::kLeft_Align == fAlign) {
100 dst->set(loc.fX, loc.fY);
101 } else if (SkPaint::kCenter_Align == fAlign) {
102 dst->set(loc.fX - SkFixedToScalar(glyph.fAdvanceX >> 1),
103 loc.fY - SkFixedToScalar(glyph.fAdvanceY >> 1));
104 } else {
105 SkASSERT(SkPaint::kRight_Align == fAlign);
106 dst->set(loc.fX - SkFixedToScalar(glyph.fAdvanceX),
107 loc.fY - SkFixedToScalar(glyph.fAdvanceY));
108 }
109 }
110 private:
111 const SkPaint::Align fAlign;
112 };
113
114 #endif
115