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 "sk_tool_utils.h"
10#include "SkBlendModePriv.h"
11#include "SkCanvas.h"
12#include "SkGradientShader.h"
13#include "SkLumaColorFilter.h"
14
15static SkScalar kSize   = 80;
16static SkScalar kInset  = 10;
17static SkColor  kColor1 = SkColorSetARGB(0xff, 0xff, 0xff, 0);
18static SkColor  kColor2 = SkColorSetARGB(0xff, 0x82, 0xff, 0);
19
20static void draw_label(SkCanvas* canvas, const char* label,
21                       const SkPoint& offset) {
22    SkPaint paint;
23    sk_tool_utils::set_portable_typeface(&paint);
24    size_t len = strlen(label);
25
26    SkScalar width = paint.measureText(label, len);
27    canvas->drawText(label, len, offset.x() - width / 2, offset.y(),
28                     paint);
29}
30
31static void draw_scene(SkCanvas* canvas, const sk_sp<SkColorFilter>& filter, SkBlendMode mode,
32                       const sk_sp<SkShader>& s1, const sk_sp<SkShader>& s2) {
33    SkPaint paint;
34    paint.setAntiAlias(true);
35    SkRect r, c, bounds = SkRect::MakeWH(kSize, kSize);
36
37    c = bounds;
38    c.fRight = bounds.centerX();
39    paint.setARGB(0x20, 0, 0, 0xff);
40    canvas->drawRect(bounds, paint);
41
42    canvas->saveLayer(&bounds, nullptr);
43
44    r = bounds;
45    r.inset(kInset, 0);
46    paint.setShader(s1);
47    paint.setColor(s1 ? SK_ColorBLACK : SkColorSetA(kColor1, 0x80));
48    canvas->drawOval(r, paint);
49    if (!s1) {
50        canvas->save();
51        canvas->clipRect(c);
52        paint.setColor(kColor1);
53        canvas->drawOval(r, paint);
54        canvas->restore();
55    }
56
57    SkPaint xferPaint;
58    xferPaint.setBlendMode(mode);
59    canvas->saveLayer(&bounds, &xferPaint);
60
61    r = bounds;
62    r.inset(0, kInset);
63    paint.setShader(s2);
64    paint.setColor(s2 ? SK_ColorBLACK : SkColorSetA(kColor2, 0x80));
65    paint.setColorFilter(filter);
66    canvas->drawOval(r, paint);
67    if (!s2) {
68        canvas->save();
69        canvas->clipRect(c);
70        paint.setColor(kColor2);
71        canvas->drawOval(r, paint);
72        canvas->restore();
73    }
74
75    canvas->restore();
76    canvas->restore();
77}
78
79class LumaFilterGM : public skiagm::GM {
80public:
81    LumaFilterGM() {
82        SkColor  g1Colors[] = { kColor1, SkColorSetA(kColor1, 0x20) };
83        SkColor  g2Colors[] = { kColor2, SkColorSetA(kColor2, 0x20) };
84        SkPoint  g1Points[] = { { 0, 0 }, { 0,     100 } };
85        SkPoint  g2Points[] = { { 0, 0 }, { kSize, 0   } };
86        SkScalar pos[] = { 0.2f, 1.0f };
87
88        fFilter = SkLumaColorFilter::Make();
89        fGr1 = SkGradientShader::MakeLinear(g1Points, g1Colors, pos, SK_ARRAY_COUNT(g1Colors),
90                                            SkShader::kClamp_TileMode);
91        fGr2 = SkGradientShader::MakeLinear(g2Points, g2Colors, pos, SK_ARRAY_COUNT(g2Colors),
92                                            SkShader::kClamp_TileMode);
93    }
94
95protected:
96
97    SkString onShortName() override {
98        return SkString("lumafilter");
99    }
100
101    SkISize onISize() override {
102        return SkISize::Make(600, 420);
103    }
104
105    void onDraw(SkCanvas* canvas) override {
106        SkBlendMode modes[] = {
107            SkBlendMode::kSrcOver,
108            SkBlendMode::kDstOver,
109            SkBlendMode::kSrcATop,
110            SkBlendMode::kDstATop,
111            SkBlendMode::kSrcIn,
112            SkBlendMode::kDstIn,
113        };
114        struct {
115            const sk_sp<SkShader>& fShader1;
116            const sk_sp<SkShader>& fShader2;
117        } shaders[] = {
118            { nullptr, nullptr },
119            { nullptr, fGr2 },
120            { fGr1, nullptr },
121            { fGr1, fGr2 },
122        };
123
124        SkScalar gridStep = kSize + 2 * kInset;
125        for (size_t i = 0; i < SK_ARRAY_COUNT(modes); ++i) {
126            draw_label(canvas, SkBlendMode_Name(modes[i]),
127                       SkPoint::Make(gridStep * (0.5f + i), 20));
128        }
129
130        for (size_t i = 0; i < SK_ARRAY_COUNT(shaders); ++i) {
131            canvas->save();
132            canvas->translate(kInset, gridStep * i + 30);
133            for (size_t m = 0; m < SK_ARRAY_COUNT(modes); ++m) {
134                draw_scene(canvas, fFilter, modes[m], shaders[i].fShader1,
135                           shaders[i].fShader2);
136                canvas->translate(gridStep, 0);
137            }
138            canvas->restore();
139        }
140    }
141
142private:
143    sk_sp<SkColorFilter>    fFilter;
144    sk_sp<SkShader>         fGr1, fGr2;
145
146    typedef skiagm::GM INHERITED;
147};
148
149//////////////////////////////////////////////////////////////////////////////
150
151DEF_GM(return new LumaFilterGM;)
152