1/*
2 * Copyright 2013 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#include "gm.h"
9#include "SkCanvas.h"
10#include "SkGradientShader.h"
11#include "SkLumaColorFilter.h"
12
13static SkScalar kSize   = 80;
14static SkScalar kInset  = 10;
15static SkColor  kColor1 = SkColorSetARGB(0xff, 0xff, 0xff, 0);
16static SkColor  kColor2 = SkColorSetARGB(0xff, 0x80, 0xff, 0);
17
18static void draw_label(SkCanvas* canvas, const char* label,
19                       const SkPoint& offset) {
20    SkPaint paint;
21    sk_tool_utils::set_portable_typeface(&paint);
22    size_t len = strlen(label);
23
24    SkScalar width = paint.measureText(label, len);
25    canvas->drawText(label, len, offset.x() - width / 2, offset.y(),
26                     paint);
27}
28
29static void draw_scene(SkCanvas* canvas, SkColorFilter* filter,
30                       SkXfermode::Mode mode, SkShader* s1,
31                       SkShader* s2) {
32    SkPaint paint;
33    paint.setAntiAlias(true);
34    SkRect r, c, bounds = SkRect::MakeWH(kSize, kSize);
35
36    c = bounds;
37    c.fRight = bounds.centerX();
38    paint.setARGB(0x20, 0, 0, 0xff);
39    canvas->drawRect(bounds, paint);
40
41    canvas->saveLayer(&bounds, NULL);
42
43    r = bounds;
44    r.inset(kInset, 0);
45    paint.setShader(s1);
46    paint.setColor(s1 ? SK_ColorBLACK : SkColorSetA(kColor1, 0x80));
47    canvas->drawOval(r, paint);
48    if (!s1) {
49        canvas->save();
50        canvas->clipRect(c);
51        paint.setColor(kColor1);
52        canvas->drawOval(r, paint);
53        canvas->restore();
54    }
55
56    SkPaint xferPaint;
57    xferPaint.setXfermodeMode(mode);
58    canvas->saveLayer(&bounds, &xferPaint);
59
60    r = bounds;
61    r.inset(0, kInset);
62    paint.setShader(s2);
63    paint.setColor(s2 ? SK_ColorBLACK : SkColorSetA(kColor2, 0x80));
64    paint.setColorFilter(filter);
65    canvas->drawOval(r, paint);
66    if (!s2) {
67        canvas->save();
68        canvas->clipRect(c);
69        paint.setColor(kColor2);
70        canvas->drawOval(r, paint);
71        canvas->restore();
72    }
73
74    canvas->restore();
75    canvas->restore();
76}
77
78class LumaFilterGM : public skiagm::GM {
79public:
80    LumaFilterGM() {
81        SkColor  g1Colors[] = { kColor1, SkColorSetA(kColor1, 0x20) };
82        SkColor  g2Colors[] = { kColor2, SkColorSetA(kColor2, 0x20) };
83        SkPoint  g1Points[] = { { 0, 0 }, { 0,     100 } };
84        SkPoint  g2Points[] = { { 0, 0 }, { kSize, 0   } };
85        SkScalar pos[] = { 0.2f, 1.0f };
86
87        fFilter.reset(SkLumaColorFilter::Create());
88        fGr1.reset(SkGradientShader::CreateLinear(g1Points,
89                                                  g1Colors,
90                                                  pos,
91                                                  SK_ARRAY_COUNT(g1Colors),
92                                                  SkShader::kClamp_TileMode));
93        fGr2.reset(SkGradientShader::CreateLinear(g2Points,
94                                                  g2Colors,
95                                                  pos,
96                                                  SK_ARRAY_COUNT(g2Colors),
97                                                  SkShader::kClamp_TileMode));
98    }
99
100protected:
101    virtual uint32_t onGetFlags() const SK_OVERRIDE {
102        return kSkipTiled_Flag;
103    }
104
105    virtual SkString onShortName() SK_OVERRIDE {
106        return SkString("lumafilter");
107    }
108
109    virtual SkISize onISize() SK_OVERRIDE {
110        return SkISize::Make(600, 420);
111    }
112
113    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
114        SkXfermode::Mode modes[] = { SkXfermode::kSrcOver_Mode,
115                                     SkXfermode::kDstOver_Mode,
116                                     SkXfermode::kSrcATop_Mode,
117                                     SkXfermode::kDstATop_Mode,
118                                     SkXfermode::kSrcIn_Mode,
119                                     SkXfermode::kDstIn_Mode,
120                                   };
121        struct {
122            SkShader*   fShader1;
123            SkShader*   fShader2;
124        } shaders[] = {
125            { NULL, NULL },
126            { NULL, fGr2 },
127            { fGr1, NULL },
128            { fGr1, fGr2 },
129        };
130
131        SkScalar gridStep = kSize + 2 * kInset;
132        for (size_t i = 0; i < SK_ARRAY_COUNT(modes); ++i) {
133            draw_label(canvas, SkXfermode::ModeName(modes[i]),
134                       SkPoint::Make(gridStep * (0.5f + i), 20));
135        }
136
137        for (size_t i = 0; i < SK_ARRAY_COUNT(shaders); ++i) {
138            canvas->save();
139            canvas->translate(kInset, gridStep * i + 30);
140            for (size_t m = 0; m < SK_ARRAY_COUNT(modes); ++m) {
141                draw_scene(canvas, fFilter, modes[m], shaders[i].fShader1,
142                           shaders[i].fShader2);
143                canvas->translate(gridStep, 0);
144            }
145            canvas->restore();
146        }
147    }
148
149private:
150    SkAutoTUnref<SkColorFilter> fFilter;
151    SkAutoTUnref<SkShader>      fGr1, fGr2;
152
153    typedef skiagm::GM INHERITED;
154};
155
156//////////////////////////////////////////////////////////////////////////////
157
158DEF_GM( return SkNEW(LumaFilterGM); )
159