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#include "include/core/SkCanvas.h"
8#include "include/effects/SkGradientShader.h"
9#include "samplecode/Sample.h"
10
11static sk_sp<SkShader> setgrad(const SkRect& r, SkColor c0, SkColor c1) {
12    SkColor colors[] = { c0, c1 };
13    SkPoint pts[] = { { r.fLeft, r.fTop }, { r.fRight, r.fTop } };
14    return SkGradientShader::MakeLinear(pts, colors, nullptr, 2, SkTileMode::kClamp);
15}
16
17static void test_alphagradients(SkCanvas* canvas) {
18    SkRect r;
19    r.setLTRB(10, 10, 410, 30);
20    SkPaint p, p2;
21    p2.setStyle(SkPaint::kStroke_Style);
22
23    p.setShader(setgrad(r, 0xFF00FF00, 0x0000FF00));
24    canvas->drawRect(r, p);
25    canvas->drawRect(r, p2);
26
27    r.offset(0, r.height() + SkIntToScalar(4));
28    p.setShader(setgrad(r, 0xFF00FF00, 0x00000000));
29    canvas->drawRect(r, p);
30    canvas->drawRect(r, p2);
31
32    r.offset(0, r.height() + SkIntToScalar(4));
33    p.setShader(setgrad(r, 0xFF00FF00, 0x00FF0000));
34    canvas->drawRect(r, p);
35    canvas->drawRect(r, p2);
36}
37
38///////////////////////////////////////////////////////////////////////////////
39
40struct GradData {
41    int             fCount;
42    const SkColor*  fColors;
43    const SkScalar* fPos;
44};
45
46static const SkColor gColors[] = {
47    SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorWHITE, SK_ColorBLACK
48};
49static const SkScalar gPos0[] = { 0, SK_Scalar1 };
50static const SkScalar gPos1[] = { SK_Scalar1/4, SK_Scalar1*3/4 };
51static const SkScalar gPos2[] = {
52    0, SK_Scalar1/8, SK_Scalar1/2, SK_Scalar1*7/8, SK_Scalar1
53};
54
55static const GradData gGradData[] = {
56    { 2, gColors, nullptr },
57    { 2, gColors, gPos0 },
58    { 2, gColors, gPos1 },
59    { 5, gColors, nullptr },
60    { 5, gColors, gPos2 }
61};
62
63static sk_sp<SkShader> MakeLinear(const SkPoint pts[2], const GradData& data, SkTileMode tm) {
64    return SkGradientShader::MakeLinear(pts, data.fColors, data.fPos, data.fCount, tm);
65}
66
67static sk_sp<SkShader> MakeRadial(const SkPoint pts[2], const GradData& data, SkTileMode tm) {
68    SkPoint center;
69    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
70               SkScalarAve(pts[0].fY, pts[1].fY));
71    return SkGradientShader::MakeRadial(center, center.fX, data.fColors,
72                                        data.fPos, data.fCount, tm);
73}
74
75static sk_sp<SkShader> MakeSweep(const SkPoint pts[2], const GradData& data, SkTileMode tm) {
76    SkPoint center;
77    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
78               SkScalarAve(pts[0].fY, pts[1].fY));
79    return SkGradientShader::MakeSweep(center.fX, center.fY, data.fColors, data.fPos, data.fCount);
80}
81
82static sk_sp<SkShader> Make2Conical(const SkPoint pts[2], const GradData& data, SkTileMode tm) {
83    SkPoint center0, center1;
84    center0.set(SkScalarAve(pts[0].fX, pts[1].fX),
85                SkScalarAve(pts[0].fY, pts[1].fY));
86    center1.set(SkScalarInterp(pts[0].fX, pts[1].fX, SkIntToScalar(3)/5),
87                SkScalarInterp(pts[0].fY, pts[1].fY, SkIntToScalar(1)/4));
88    return SkGradientShader::MakeTwoPointConical(
89                            center1, (pts[1].fX - pts[0].fX) / 7,
90                            center0, (pts[1].fX - pts[0].fX) / 2,
91                            data.fColors, data.fPos, data.fCount, tm);
92}
93
94static sk_sp<SkShader> Make2ConicalConcentric(const SkPoint pts[2], const GradData& data,
95                                       SkTileMode tm) {
96    SkPoint center;
97    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
98               SkScalarAve(pts[0].fY, pts[1].fY));
99    return SkGradientShader::MakeTwoPointConical(
100                            center, (pts[1].fX - pts[0].fX) / 7,
101                            center, (pts[1].fX - pts[0].fX) / 2,
102                            data.fColors, data.fPos, data.fCount, tm);
103}
104
105typedef sk_sp<SkShader> (*GradMaker)(const SkPoint pts[2], const GradData& data, SkTileMode tm);
106
107static const GradMaker gGradMakers[] = {
108    MakeLinear, MakeRadial, MakeSweep, Make2Conical, Make2ConicalConcentric
109};
110
111///////////////////////////////////////////////////////////////////////////////
112
113class GradientsView : public Sample {
114public:
115    GradientsView() {
116        this->setBGColor(0xFFDDDDDD);
117    }
118
119protected:
120    SkString name() override { return SkString("Gradients"); }
121
122    void onDrawContent(SkCanvas* canvas) override {
123        SkPoint pts[2] = {
124            { 0, 0 },
125            { SkIntToScalar(100), SkIntToScalar(100) }
126        };
127        SkRect r = { 0, 0, SkIntToScalar(100), SkIntToScalar(100) };
128        SkPaint paint;
129        paint.setDither(true);
130
131        canvas->save();
132        canvas->translate(SkIntToScalar(20), SkIntToScalar(10));
133
134        for (int tm = 0; tm < kSkTileModeCount; ++tm) {
135            canvas->save();
136            for (size_t i = 0; i < SK_ARRAY_COUNT(gGradData); i++) {
137                canvas->save();
138                for (size_t j = 0; j < SK_ARRAY_COUNT(gGradMakers); j++) {
139                    paint.setShader(gGradMakers[j](pts, gGradData[i], (SkTileMode)tm));
140                    canvas->drawRect(r, paint);
141                    canvas->translate(0, SkIntToScalar(120));
142                }
143                canvas->restore();
144                canvas->translate(SkIntToScalar(120), 0);
145            }
146            canvas->restore();
147            canvas->translate(SK_ARRAY_COUNT(gGradData)*SkIntToScalar(120), 0);
148        }
149        canvas->restore();
150
151        canvas->translate(0, SkIntToScalar(370));
152        if (false) { // avoid bit rot, suppress warning
153            test_alphagradients(canvas);
154        }
155    }
156
157private:
158    using INHERITED = Sample;
159};
160
161///////////////////////////////////////////////////////////////////////////////
162
163DEF_SAMPLE( return new GradientsView(); )
164