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 #include "tools/fonts/FontToolUtils.h"
25
26 // NOTE: The positions define hardstops for the red and green borders. For the repeating degenerate
27 // gradients, that means the red and green are never visible, so the average color used should only
28 // be based off of the white, blue, black blend.
29 static const SkColor COLORS[] = { SK_ColorRED, SK_ColorWHITE, SK_ColorBLUE,
30 SK_ColorBLACK, SK_ColorGREEN };
31 static const SkScalar POS[] = { 0.0, 0.0, 0.5, 1.0, 1.0 };
32 static const int COLOR_CT = std::size(COLORS);
33
34 static const SkTileMode TILE_MODES[] = { SkTileMode::kDecal,
35 SkTileMode::kRepeat,
36 SkTileMode::kMirror,
37 SkTileMode::kClamp };
38 static const char* TILE_NAMES[] = { "decal", "repeat", "mirror", "clamp" };
39 static const int TILE_MODE_CT = std::size(TILE_MODES);
40
41 static constexpr int TILE_SIZE = 100;
42 static constexpr int TILE_GAP = 10;
43
44 static const SkPoint CENTER = SkPoint::Make(TILE_SIZE / 2, TILE_SIZE / 2);
45
46 typedef sk_sp<SkShader> (*GradientFactory)(SkTileMode tm);
47
draw_tile_header(SkCanvas * canvas)48 static void draw_tile_header(SkCanvas* canvas) {
49 canvas->save();
50
51 SkFont font(ToolUtils::DefaultPortableTypeface(), 12);
52 for (int i = 0; i < TILE_MODE_CT; ++i) {
53 canvas->drawString(TILE_NAMES[i], 0, 0, font, SkPaint());
54 canvas->translate(TILE_SIZE + TILE_GAP, 0);
55 }
56
57 canvas->restore();
58
59 // Now adjust to start at rows below the header
60 canvas->translate(0, 2 * TILE_GAP);
61 }
62
draw_row(SkCanvas * canvas,const char * desc,GradientFactory factory)63 static void draw_row(SkCanvas* canvas, const char* desc, GradientFactory factory) {
64 canvas->save();
65
66 SkPaint text;
67 text.setAntiAlias(true);
68
69 SkFont font(ToolUtils::DefaultPortableTypeface(), 12);
70
71 canvas->translate(0, TILE_GAP);
72 canvas->drawString(desc, 0, 0, font, text);
73 canvas->translate(0, TILE_GAP);
74
75 SkPaint paint;
76 paint.setColor(SK_ColorBLACK);
77 paint.setStyle(SkPaint::kStrokeAndFill_Style);
78 paint.setStrokeWidth(2.0f);
79
80 for (int i = 0; i < TILE_MODE_CT; ++i) {
81 paint.setShader(factory(TILE_MODES[i]));
82 canvas->drawRect(SkRect::MakeWH(TILE_SIZE, TILE_SIZE), paint);
83 canvas->translate(TILE_SIZE + TILE_GAP, 0);
84 }
85
86 canvas->restore();
87
88 // Now adjust to start the next row below this one (1 gap for text and 2 gap for margin)
89 canvas->translate(0, 3 * TILE_GAP + TILE_SIZE);
90 }
91
make_linear(SkTileMode mode)92 static sk_sp<SkShader> make_linear(SkTileMode mode) {
93 // Same position
94 SkPoint pts[2] = {CENTER, CENTER};
95 return SkGradientShader::MakeLinear(pts, COLORS, POS, COLOR_CT, mode);
96 }
97
make_radial(SkTileMode mode)98 static sk_sp<SkShader> make_radial(SkTileMode mode) {
99 // Radius = 0
100 return SkGradientShader::MakeRadial(CENTER, 0.0, COLORS, POS, COLOR_CT, mode);
101 }
102
make_sweep(SkTileMode mode)103 static sk_sp<SkShader> make_sweep(SkTileMode mode) {
104 // Start and end angles at 45
105 static constexpr SkScalar SWEEP_ANG = 45.0;
106 return SkGradientShader::MakeSweep(CENTER.fX, CENTER.fY, COLORS, POS, COLOR_CT, mode,
107 SWEEP_ANG, SWEEP_ANG, 0, nullptr);
108 }
109
make_sweep_zero_ang(SkTileMode mode)110 static sk_sp<SkShader> make_sweep_zero_ang(SkTileMode mode) {
111 // Start and end angles at 0
112 return SkGradientShader::MakeSweep(CENTER.fX, CENTER.fY, COLORS, POS, COLOR_CT, mode,
113 0.0, 0.0, 0, nullptr);
114 }
115
make_2pt_conic(SkTileMode mode)116 static sk_sp<SkShader> make_2pt_conic(SkTileMode mode) {
117 // Start and end radius = TILE_SIZE, same position
118 return SkGradientShader::MakeTwoPointConical(CENTER, TILE_SIZE / 2, CENTER, TILE_SIZE / 2,
119 COLORS, POS, COLOR_CT, mode);
120 }
121
make_2pt_conic_zero_rad(SkTileMode mode)122 static sk_sp<SkShader> make_2pt_conic_zero_rad(SkTileMode mode) {
123 // Start and end radius = 0, same position
124 return SkGradientShader::MakeTwoPointConical(CENTER, 0.0, CENTER, 0.0, COLORS, POS,
125 COLOR_CT, mode);
126 }
127
128 class DegenerateGradientGM : public skiagm::GM {
129 public:
DegenerateGradientGM()130 DegenerateGradientGM() {
131
132 }
133
134 protected:
getName() const135 SkString getName() const override { return SkString("degenerate_gradients"); }
136
getISize()137 SkISize getISize() override { return SkISize::Make(800, 800); }
138
onDraw(SkCanvas * canvas)139 void onDraw(SkCanvas* canvas) override {
140 canvas->translate(3 * TILE_GAP, 3 * TILE_GAP);
141 draw_tile_header(canvas);
142
143 draw_row(canvas, "linear: empty, blue, blue, green", make_linear);
144 draw_row(canvas, "radial: empty, blue, blue, green", make_radial);
145 draw_row(canvas, "sweep-0: empty, blue, blue, green", make_sweep_zero_ang);
146 draw_row(canvas, "sweep-45: empty, blue, blue, red 45 degree sector then green",
147 make_sweep);
148 draw_row(canvas, "2pt-conic-0: empty, blue, blue, green", make_2pt_conic_zero_rad);
149 draw_row(canvas, "2pt-conic-1: empty, blue, blue, full red circle on green",
150 make_2pt_conic);
151 }
152
153 private:
154 using INHERITED = skiagm::GM;
155 };
156
157 DEF_GM(return new DegenerateGradientGM;)
158