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 SkLayerDrawLooper_DEFINED
9#define SkLayerDrawLooper_DEFINED
10
11#include "include/core/SkBlendMode.h"
12#include "include/core/SkDrawLooper.h"
13#include "include/core/SkPaint.h"
14#include "include/core/SkPoint.h"
15
16/**
17 * DEPRECATED: No longer supported by Skia.
18 */
19class SK_API SkLayerDrawLooper : public SkDrawLooper {
20public:
21 ~SkLayerDrawLooper() override;
22
23 /**
24 * Bits specifies which aspects of the layer's paint should replace the
25 * corresponding aspects on the draw's paint.
26 * kEntirePaint_Bits means use the layer's paint completely.
27 * 0 means ignore the layer's paint... except for fColorMode, which is
28 * always applied.
29 */
30 enum Bits {
31 kStyle_Bit = 1 << 0, //!< use this layer's Style/stroke settings
32 kPathEffect_Bit = 1 << 2, //!< use this layer's patheffect
33 kMaskFilter_Bit = 1 << 3, //!< use this layer's maskfilter
34 kShader_Bit = 1 << 4, //!< use this layer's shader
35 kColorFilter_Bit = 1 << 5, //!< use this layer's colorfilter
36 kXfermode_Bit = 1 << 6, //!< use this layer's xfermode
37
38 // unsupported kTextSkewX_Bit = 1 << 1,
39
40 /**
41 * Use the layer's paint entirely, with these exceptions:
42 * - We never override the draw's paint's text_encoding, since that is
43 * used to interpret the text/len parameters in draw[Pos]Text.
44 * - Color is always computed using the LayerInfo's fColorMode.
45 */
46 kEntirePaint_Bits = -1
47
48 };
49 typedef int32_t BitFlags;
50
51 /**
52 * Info for how to apply the layer's paint and offset.
53 *
54 * fColorMode controls how we compute the final color for the layer:
55 * The layer's paint's color is treated as the SRC
56 * The draw's paint's color is treated as the DST
57 * final-color = Mode(layers-color, draws-color);
58 * Any SkBlendMode will work. Two common choices are:
59 * kSrc: to use the layer's color, ignoring the draw's
60 * kDst: to just keep the draw's color, ignoring the layer's
61 */
62 struct SK_API LayerInfo {
63 BitFlags fPaintBits;
64 SkBlendMode fColorMode;
65 SkVector fOffset;
66 bool fPostTranslate; //!< applies to fOffset
67
68 /**
69 * Initial the LayerInfo. Defaults to settings that will draw the
70 * layer with no changes: e.g.
71 * fPaintBits == 0
72 * fColorMode == kDst_Mode
73 * fOffset == (0, 0)
74 */
75 LayerInfo();
76 };
77
78 SkDrawLooper::Context* makeContext(SkArenaAlloc*) const override;
79
80 bool asABlurShadow(BlurShadowRec* rec) const override;
81
82protected:
83 SkLayerDrawLooper();
84
85 void flatten(SkWriteBuffer&) const override;
86
87private:
88 SK_FLATTENABLE_HOOKS(SkLayerDrawLooper)
89
90 struct Rec {
91 Rec* fNext;
92 SkPaint fPaint;
93 LayerInfo fInfo;
94 };
95 Rec* fRecs;
96 int fCount;
97
98 // state-machine during the init/next cycle
99 class LayerDrawLooperContext : public SkDrawLooper::Context {
100 public:
101 explicit LayerDrawLooperContext(const SkLayerDrawLooper* looper);
102
103 protected:
104 bool next(Info*, SkPaint* paint) override;
105
106 private:
107 Rec* fCurrRec;
108
109 static void ApplyInfo(SkPaint* dst, const SkPaint& src, const LayerInfo&);
110 };
111
112 typedef SkDrawLooper INHERITED;
113
114public:
115 class SK_API Builder {
116 public:
117 Builder();
118 ~Builder();
119
120 /**
121 * Call for each layer you want to add (from top to bottom).
122 * This returns a paint you can modify, but that ptr is only valid until
123 * the next call made to addLayer().
124 */
125 SkPaint* addLayer(const LayerInfo&);
126
127 /**
128 * This layer will draw with the original paint, at the specified offset
129 */
130 void addLayer(SkScalar dx, SkScalar dy);
131
132 /**
133 * This layer will with the original paint and no offset.
134 */
135 void addLayer() { this->addLayer(0, 0); }
136
137 /// Similar to addLayer, but adds a layer to the top.
138 SkPaint* addLayerOnTop(const LayerInfo&);
139
140 /**
141 * Pass list of layers on to newly built looper and return it. This will
142 * also reset the builder, so it can be used to build another looper.
143 */
144 sk_sp<SkDrawLooper> detach();
145
146 private:
147 Rec* fRecs;
148 Rec* fTopRec;
149 int fCount;
150 };
151};
152
153#endif
154