1
2/*
3 * Copyright 2014 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9#include "gm.h"
10#include "SkGradientShader.h"
11#include "SkPatchUtils.h"
12
13static SkShader* make_shader() {
14    const SkColor colors[] = {
15        SK_ColorRED, SK_ColorCYAN, SK_ColorGREEN, SK_ColorWHITE, SK_ColorMAGENTA, SK_ColorBLUE,
16        SK_ColorYELLOW,
17    };
18    const SkPoint pts[] = { { 100.f / 4.f, 0.f }, { 3.f * 100.f / 4.f, 100.f } };
19
20    return SkGradientShader::CreateLinear(pts, colors, NULL, SK_ARRAY_COUNT(colors),
21                                          SkShader::kMirror_TileMode);
22}
23
24static void draw_control_points(SkCanvas* canvas, const SkPoint cubics[12]) {
25    //draw control points
26    SkPaint paint;
27    SkPoint bottom[SkPatchUtils::kNumPtsCubic];
28    SkPatchUtils::getBottomCubic(cubics, bottom);
29    SkPoint top[SkPatchUtils::kNumPtsCubic];
30    SkPatchUtils::getTopCubic(cubics, top);
31    SkPoint left[SkPatchUtils::kNumPtsCubic];
32    SkPatchUtils::getLeftCubic(cubics, left);
33    SkPoint right[SkPatchUtils::kNumPtsCubic];
34    SkPatchUtils::getRightCubic(cubics, right);
35
36    paint.setColor(SK_ColorBLACK);
37    paint.setStrokeWidth(0.5f);
38    SkPoint corners[4] = { bottom[0], bottom[3], top[0], top[3] };
39    canvas->drawPoints(SkCanvas::kLines_PointMode, 4, bottom, paint);
40    canvas->drawPoints(SkCanvas::kLines_PointMode, 2, bottom + 1, paint);
41    canvas->drawPoints(SkCanvas::kLines_PointMode, 4, top, paint);
42    canvas->drawPoints(SkCanvas::kLines_PointMode, 4, left, paint);
43    canvas->drawPoints(SkCanvas::kLines_PointMode, 4, right, paint);
44
45    canvas->drawPoints(SkCanvas::kLines_PointMode, 2, top + 1, paint);
46    canvas->drawPoints(SkCanvas::kLines_PointMode, 2, left + 1, paint);
47    canvas->drawPoints(SkCanvas::kLines_PointMode, 2, right + 1, paint);
48
49    paint.setStrokeWidth(2);
50
51    paint.setColor(SK_ColorRED);
52    canvas->drawPoints(SkCanvas::kPoints_PointMode, 4, corners, paint);
53
54    paint.setColor(SK_ColorBLUE);
55    canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, bottom + 1, paint);
56
57    paint.setColor(SK_ColorCYAN);
58    canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, top + 1, paint);
59
60    paint.setColor(SK_ColorYELLOW);
61    canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, left + 1, paint);
62
63    paint.setColor(SK_ColorGREEN);
64    canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, right + 1, paint);
65}
66
67namespace skiagm {
68/**
69 * This GM draws a cubics coons patch using the specialized call SkCanvas::drawPatch.
70 */
71class SkPatchGM : public GM {
72
73public:
74    SkPatchGM() {
75        this->setBGColor(0xFFFFFFFF);
76    }
77
78protected:
79    SkString onShortName() override {
80        return SkString("patch_primitive");
81    }
82
83    SkISize onISize() override {
84        return SkISize::Make(800, 800);
85    }
86
87    void onDraw(SkCanvas* canvas) override {
88
89        SkPaint paint;
90
91        // The order of the colors and points is clockwise starting at upper-left corner.
92        const SkPoint cubics[SkPatchUtils::kNumCtrlPts] = {
93            //top points
94            {100,100},{150,50},{250,150}, {300,100},
95            //right points
96            {250, 150},{350,250},
97            //bottom points
98            {300,300},{250,250},{150,350},{100,300},
99            //left points
100            {50,250},{150,150}
101        };
102
103        const SkColor colors[SkPatchUtils::kNumCorners] = {
104            SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorCYAN
105        };
106        const SkPoint texCoords[SkPatchUtils::kNumCorners] = {
107            {0.0f, 0.0f}, {100.0f, 0.0f}, {100.0f,100.0f}, {0.0f, 100.0f}}
108        ;
109
110        const SkXfermode::Mode modes[] = {
111            SkXfermode::kSrc_Mode,
112            SkXfermode::kDst_Mode,
113            SkXfermode::kModulate_Mode,
114        };
115
116        SkAutoTUnref<SkShader> shader(make_shader());
117
118        canvas->save();
119        for (int y = 0; y < 3; y++) {
120            SkAutoTUnref<SkXfermode> xfer(SkXfermode::Create(modes[y]));
121
122            for (int x = 0; x < 4; x++) {
123                canvas->save();
124                canvas->translate(x * 350.0f, y * 350.0f);
125                switch (x) {
126                    case 0:
127                        canvas->drawPatch(cubics, NULL, NULL, xfer, paint);
128                        break;
129                    case 1:
130                        canvas->drawPatch(cubics, colors, NULL, xfer, paint);
131                        break;
132                    case 2:
133                        paint.setShader(shader);
134                        canvas->drawPatch(cubics, NULL, texCoords, xfer, paint);
135                        paint.setShader(NULL);
136                        break;
137                    case 3:
138                        paint.setShader(shader);
139                        canvas->drawPatch(cubics, colors, texCoords, xfer, paint);
140                        paint.setShader(NULL);
141                        break;
142                    default:
143                        break;
144                }
145
146                draw_control_points(canvas, cubics);
147                canvas->restore();
148            }
149        }
150        canvas->restore();
151    }
152
153private:
154    typedef GM INHERITED;
155};
156
157DEF_GM(return SkNEW(SkPatchGM); )
158
159}
160