1 /*
2 * Copyright 2018 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/gm.h"
9 #include "include/core/SkCanvas.h"
10 #include "include/core/SkColor.h"
11 #include "include/core/SkFont.h"
12 #include "include/core/SkPaint.h"
13 #include "include/core/SkPoint.h"
14 #include "include/core/SkRect.h"
15 #include "include/core/SkRefCnt.h"
16 #include "include/core/SkScalar.h"
17 #include "include/core/SkShader.h"
18 #include "include/core/SkSize.h"
19 #include "include/core/SkString.h"
20 #include "include/core/SkTileMode.h"
21 #include "include/core/SkTypes.h"
22 #include "include/effects/SkGradientShader.h"
23 #include "tools/ToolUtils.h"
24
25 // NOTE: The positions define hardstops for the red and green borders. For the repeating degenerate
26 // gradients, that means the red and green are never visible, so the average color used should only
27 // be based off of the white, blue, black blend.
28 static const SkColor COLORS[] = { SK_ColorRED, SK_ColorWHITE, SK_ColorBLUE,
29 SK_ColorBLACK, SK_ColorGREEN };
30 static const SkScalar POS[] = { 0.0, 0.0, 0.5, 1.0, 1.0 };
31 static const int COLOR_CT = SK_ARRAY_COUNT(COLORS);
32
33 static const SkTileMode TILE_MODES[] = { SkTileMode::kDecal,
34 SkTileMode::kRepeat,
35 SkTileMode::kMirror,
36 SkTileMode::kClamp };
37 static const char* TILE_NAMES[] = { "decal", "repeat", "mirror", "clamp" };
38 static const int TILE_MODE_CT = SK_ARRAY_COUNT(TILE_MODES);
39
40 static constexpr int TILE_SIZE = 100;
41 static constexpr int TILE_GAP = 10;
42
43 static const SkPoint CENTER = SkPoint::Make(TILE_SIZE / 2, TILE_SIZE / 2);
44
45 typedef sk_sp<SkShader> (*GradientFactory)(SkTileMode tm);
46
draw_tile_header(SkCanvas * canvas)47 static void draw_tile_header(SkCanvas* canvas) {
48 canvas->save();
49
50 SkFont font(ToolUtils::create_portable_typeface(), 12);
51 for (int i = 0; i < TILE_MODE_CT; ++i) {
52 canvas->drawString(TILE_NAMES[i], 0, 0, font, SkPaint());
53 canvas->translate(TILE_SIZE + TILE_GAP, 0);
54 }
55
56 canvas->restore();
57
58 // Now adjust to start at rows below the header
59 canvas->translate(0, 2 * TILE_GAP);
60 }
61
draw_row(SkCanvas * canvas,const char * desc,GradientFactory factory)62 static void draw_row(SkCanvas* canvas, const char* desc, GradientFactory factory) {
63 canvas->save();
64
65 SkPaint text;
66 text.setAntiAlias(true);
67
68 SkFont font(ToolUtils::create_portable_typeface(), 12);
69
70 canvas->translate(0, TILE_GAP);
71 canvas->drawString(desc, 0, 0, font, text);
72 canvas->translate(0, TILE_GAP);
73
74 SkPaint paint;
75 paint.setColor(SK_ColorBLACK);
76 paint.setStyle(SkPaint::kStrokeAndFill_Style);
77 paint.setStrokeWidth(2.0f);
78
79 for (int i = 0; i < TILE_MODE_CT; ++i) {
80 paint.setShader(factory(TILE_MODES[i]));
81 canvas->drawRect(SkRect::MakeWH(TILE_SIZE, TILE_SIZE), paint);
82 canvas->translate(TILE_SIZE + TILE_GAP, 0);
83 }
84
85 canvas->restore();
86
87 // Now adjust to start the next row below this one (1 gap for text and 2 gap for margin)
88 canvas->translate(0, 3 * TILE_GAP + TILE_SIZE);
89 }
90
make_linear(SkTileMode mode)91 static sk_sp<SkShader> make_linear(SkTileMode mode) {
92 // Same position
93 SkPoint pts[2] = {CENTER, CENTER};
94 return SkGradientShader::MakeLinear(pts, COLORS, POS, COLOR_CT, mode);
95 }
96
make_radial(SkTileMode mode)97 static sk_sp<SkShader> make_radial(SkTileMode mode) {
98 // Radius = 0
99 return SkGradientShader::MakeRadial(CENTER, 0.0, COLORS, POS, COLOR_CT, mode);
100 }
101
make_sweep(SkTileMode mode)102 static sk_sp<SkShader> make_sweep(SkTileMode mode) {
103 // Start and end angles at 45
104 static constexpr SkScalar SWEEP_ANG = 45.0;
105 return SkGradientShader::MakeSweep(CENTER.fX, CENTER.fY, COLORS, POS, COLOR_CT, mode,
106 SWEEP_ANG, SWEEP_ANG, 0, nullptr);
107 }
108
make_sweep_zero_ang(SkTileMode mode)109 static sk_sp<SkShader> make_sweep_zero_ang(SkTileMode mode) {
110 // Start and end angles at 0
111 return SkGradientShader::MakeSweep(CENTER.fX, CENTER.fY, COLORS, POS, COLOR_CT, mode,
112 0.0, 0.0, 0, nullptr);
113 }
114
make_2pt_conic(SkTileMode mode)115 static sk_sp<SkShader> make_2pt_conic(SkTileMode mode) {
116 // Start and end radius = TILE_SIZE, same position
117 return SkGradientShader::MakeTwoPointConical(CENTER, TILE_SIZE / 2, CENTER, TILE_SIZE / 2,
118 COLORS, POS, COLOR_CT, mode);
119 }
120
make_2pt_conic_zero_rad(SkTileMode mode)121 static sk_sp<SkShader> make_2pt_conic_zero_rad(SkTileMode mode) {
122 // Start and end radius = 0, same position
123 return SkGradientShader::MakeTwoPointConical(CENTER, 0.0, CENTER, 0.0, COLORS, POS,
124 COLOR_CT, mode);
125 }
126
127 class DegenerateGradientGM : public skiagm::GM {
128 public:
DegenerateGradientGM()129 DegenerateGradientGM() {
130
131 }
132
133 protected:
onShortName()134 SkString onShortName() override {
135 return SkString("degenerate_gradients");
136 }
137
onISize()138 SkISize onISize() override {
139 return SkISize::Make(800, 800);
140 }
141
onDraw(SkCanvas * canvas)142 void onDraw(SkCanvas* canvas) override {
143 canvas->translate(3 * TILE_GAP, 3 * TILE_GAP);
144 draw_tile_header(canvas);
145
146 draw_row(canvas, "linear: empty, blue, blue, green", make_linear);
147 draw_row(canvas, "radial: empty, blue, blue, green", make_radial);
148 draw_row(canvas, "sweep-0: empty, blue, blue, green", make_sweep_zero_ang);
149 draw_row(canvas, "sweep-45: empty, blue, blue, red 45 degree sector then green",
150 make_sweep);
151 draw_row(canvas, "2pt-conic-0: empty, blue, blue, green", make_2pt_conic_zero_rad);
152 draw_row(canvas, "2pt-conic-1: empty, blue, blue, full red circle on green",
153 make_2pt_conic);
154 }
155
156 private:
157 using INHERITED = skiagm::GM;
158 };
159
160 DEF_GM(return new DegenerateGradientGM;)
161