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