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 /*
9 * This GM presents a variety of gradients meant to test the correctness of the analytic
10 * GrUnrolledBinaryGradientColorizer, which can handle arbitrary gradients with 1 to 8 interpolation
11 * intervals. These intervals can be either hardstops or smooth color transitions.
12 *
13 * It produces an image similar to that of GM_hardstop_gradients, but is arranged as follows:
14 *
15 * | Clamp |
16 * |________________|
17 * | M1 M2 M3 M4 |
18 * ___________|________________|
19 * 1 |
20 * 2 |
21 * 3 |
22 * 4 |
23 * 5 |
24 * 6 |
25 * 7 |
26 * 8 |
27 * The M-modes are different ways of interlveaving hardstops with smooth transitions:
28 * - M1 = All smooth transitions
29 * - M2 = All hard stops
30 * - M5 = Alternating smooth then hard
31 * - M6 = Alternating hard then smooth
32 *
33 * Only clamping is tested since this is focused more on within the interpolation region behavior,
34 * compared to overall behavior.
35 */
36
37 #include "gm.h"
38
39 #include "SkGradientShader.h"
40
41 // All positions must be divided by the target interval count, which will produce the expected
42 // normalized position array for that interval number (assuming an appropriate color count is
43 // provided).
44 const int M1_POSITIONS[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8 };
45 const int M2_POSITIONS[] = { 0, 1,1, 2,2, 3,3, 4,4, 5,5, 6,6, 7,7, 8 };
46 const int M3_POSITIONS[] = { 0, 1, 2,2, 3, 4,4, 5, 6,6, 7, 8 };
47 const int M4_POSITIONS[] = { 0, 1,1, 2, 3,3, 4, 5,5, 6, 7,7, 8 };
48
49 // Color count = index of first occurrence of interval count value in Mx_POSITIONS array.
50 const int INT1_COLOR_COUNTS[] = { 2, 2, 2, 2 };
51 const int INT2_COLOR_COUNTS[] = { 3, 4, 3, 4 };
52 const int INT3_COLOR_COUNTS[] = { 4, 6, 5, 5 };
53 const int INT4_COLOR_COUNTS[] = { 5, 8, 6, 7 };
54 const int INT5_COLOR_COUNTS[] = { 6, 10, 8, 8 };
55 const int INT6_COLOR_COUNTS[] = { 7, 12, 9, 10 };
56 const int INT7_COLOR_COUNTS[] = { 8, 14, 11, 11 };
57 const int INT8_COLOR_COUNTS[] = { 9, 16, 12, 13 };
58
59 // Cycle through defined colors for positions 0 through 8.
60 const SkColor COLORS[] = {
61 SK_ColorDKGRAY,
62 SK_ColorRED,
63 SK_ColorYELLOW,
64 SK_ColorGREEN,
65 SK_ColorCYAN,
66 SK_ColorBLUE,
67 SK_ColorMAGENTA,
68 SK_ColorBLACK,
69 SK_ColorLTGRAY
70 };
71
72 const int* INTERVAL_COLOR_COUNTS[] = {
73 INT1_COLOR_COUNTS,
74 INT2_COLOR_COUNTS,
75 INT3_COLOR_COUNTS,
76 INT4_COLOR_COUNTS,
77 INT5_COLOR_COUNTS,
78 INT6_COLOR_COUNTS,
79 INT7_COLOR_COUNTS,
80 INT8_COLOR_COUNTS
81 };
82 const int COLOR_COUNT = SK_ARRAY_COUNT(COLORS);
83
84 const int* M_POSITIONS[] = {
85 M1_POSITIONS,
86 M2_POSITIONS,
87 M3_POSITIONS,
88 M4_POSITIONS
89 };
90
91 const int WIDTH = 500;
92 const int HEIGHT = 500;
93
94 const int NUM_ROWS = 8;
95 const int NUM_COLS = 4;
96
97 const int CELL_WIDTH = WIDTH / NUM_COLS;
98 const int CELL_HEIGHT = HEIGHT / NUM_ROWS;
99
100 const int PAD_WIDTH = 3;
101 const int PAD_HEIGHT = 3;
102
103 const int RECT_WIDTH = CELL_WIDTH - (2 * PAD_WIDTH);
104 const int RECT_HEIGHT = CELL_HEIGHT - (2 * PAD_HEIGHT);
105
shade_rect(SkCanvas * canvas,sk_sp<SkShader> shader,int cellRow,int cellCol)106 static void shade_rect(SkCanvas* canvas, sk_sp<SkShader> shader, int cellRow, int cellCol) {
107 SkPaint paint;
108 paint.setShader(shader);
109
110 canvas->save();
111 canvas->translate(SkIntToScalar(cellCol * CELL_WIDTH + PAD_WIDTH),
112 SkIntToScalar(cellRow * CELL_HEIGHT + PAD_HEIGHT));
113
114 const SkRect rect = SkRect::MakeWH(SkIntToScalar(RECT_WIDTH), SkIntToScalar(RECT_HEIGHT));
115 canvas->drawRect(rect, paint);
116 canvas->restore();
117 }
118
119 class AnalyticGradientShaderGM : public skiagm::GM {
120 public:
AnalyticGradientShaderGM()121 AnalyticGradientShaderGM() {
122
123 }
124
125 protected:
onShortName()126 SkString onShortName() override {
127 return SkString("analytic_gradients");
128 }
129
onISize()130 SkISize onISize() override {
131 return SkISize::Make(1024, 512);
132 }
133
onDraw(SkCanvas * canvas)134 void onDraw(SkCanvas* canvas) override {
135 const SkPoint points[2] = { SkPoint::Make(0, 0), SkPoint::Make(RECT_WIDTH, 0.0) };
136
137 for (int cellRow = 0; cellRow < NUM_ROWS; cellRow++) {
138 // Each interval has 4 different color counts, one per mode
139 const int* colorCounts = INTERVAL_COLOR_COUNTS[cellRow]; // Has len = 4
140
141 for (int cellCol = 0; cellCol < NUM_COLS; cellCol++) {
142 // create_gradient_points(cellRow, cellCol, points);
143
144 // Get the color count dependent on interval and mode
145 int colorCount = colorCounts[cellCol];
146 // Get the positions given the mode
147 const int* layout = M_POSITIONS[cellCol];
148
149 // Collect positions and colors specific to the interval+mode normalizing the
150 // position based on the interval count (== cellRow+1)
151 SkAutoSTMalloc<4, SkColor> colors(colorCount);
152 SkAutoSTMalloc<4, SkScalar> positions(colorCount);
153 int j = 0;
154 for (int i = 0; i < colorCount; i++) {
155 positions[i] = SkIntToScalar(layout[i]) / (cellRow + 1);
156 colors[i] = COLORS[j % COLOR_COUNT];
157 j++;
158 }
159
160 auto shader = SkGradientShader::MakeLinear(
161 points,
162 colors.get(),
163 positions.get(),
164 colorCount,
165 SkShader::kClamp_TileMode,
166 0,
167 nullptr);
168
169 shade_rect(canvas, shader, cellRow, cellCol);
170 }
171 }
172 }
173
174 private:
175 typedef skiagm::GM INHERITED;
176 };
177
178 DEF_GM(return new AnalyticGradientShaderGM;)
179