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/gm.h"
38 #include "include/core/SkCanvas.h"
39 #include "include/core/SkColor.h"
40 #include "include/core/SkPaint.h"
41 #include "include/core/SkPoint.h"
42 #include "include/core/SkRect.h"
43 #include "include/core/SkRefCnt.h"
44 #include "include/core/SkScalar.h"
45 #include "include/core/SkShader.h"
46 #include "include/core/SkSize.h"
47 #include "include/core/SkString.h"
48 #include "include/core/SkTileMode.h"
49 #include "include/core/SkTypes.h"
50 #include "include/effects/SkGradientShader.h"
51 #include "include/private/SkTemplates.h"
52
53 // All positions must be divided by the target interval count, which will produce the expected
54 // normalized position array for that interval number (assuming an appropriate color count is
55 // provided).
56 const int M1_POSITIONS[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8 };
57 const int M2_POSITIONS[] = { 0, 1,1, 2,2, 3,3, 4,4, 5,5, 6,6, 7,7, 8 };
58 const int M3_POSITIONS[] = { 0, 1, 2,2, 3, 4,4, 5, 6,6, 7, 8 };
59 const int M4_POSITIONS[] = { 0, 1,1, 2, 3,3, 4, 5,5, 6, 7,7, 8 };
60
61 // Color count = index of first occurrence of interval count value in Mx_POSITIONS array.
62 const int INT1_COLOR_COUNTS[] = { 2, 2, 2, 2 };
63 const int INT2_COLOR_COUNTS[] = { 3, 4, 3, 4 };
64 const int INT3_COLOR_COUNTS[] = { 4, 6, 5, 5 };
65 const int INT4_COLOR_COUNTS[] = { 5, 8, 6, 7 };
66 const int INT5_COLOR_COUNTS[] = { 6, 10, 8, 8 };
67 const int INT6_COLOR_COUNTS[] = { 7, 12, 9, 10 };
68 const int INT7_COLOR_COUNTS[] = { 8, 14, 11, 11 };
69 const int INT8_COLOR_COUNTS[] = { 9, 16, 12, 13 };
70
71 // Cycle through defined colors for positions 0 through 8.
72 const SkColor COLORS[] = {
73 SK_ColorDKGRAY,
74 SK_ColorRED,
75 SK_ColorYELLOW,
76 SK_ColorGREEN,
77 SK_ColorCYAN,
78 SK_ColorBLUE,
79 SK_ColorMAGENTA,
80 SK_ColorBLACK,
81 SK_ColorLTGRAY
82 };
83
84 const int* INTERVAL_COLOR_COUNTS[] = {
85 INT1_COLOR_COUNTS,
86 INT2_COLOR_COUNTS,
87 INT3_COLOR_COUNTS,
88 INT4_COLOR_COUNTS,
89 INT5_COLOR_COUNTS,
90 INT6_COLOR_COUNTS,
91 INT7_COLOR_COUNTS,
92 INT8_COLOR_COUNTS
93 };
94 const int COLOR_COUNT = SK_ARRAY_COUNT(COLORS);
95
96 const int* M_POSITIONS[] = {
97 M1_POSITIONS,
98 M2_POSITIONS,
99 M3_POSITIONS,
100 M4_POSITIONS
101 };
102
103 const int WIDTH = 500;
104 const int HEIGHT = 500;
105
106 const int NUM_ROWS = 8;
107 const int NUM_COLS = 4;
108
109 const int CELL_WIDTH = WIDTH / NUM_COLS;
110 const int CELL_HEIGHT = HEIGHT / NUM_ROWS;
111
112 const int PAD_WIDTH = 3;
113 const int PAD_HEIGHT = 3;
114
115 const int RECT_WIDTH = CELL_WIDTH - (2 * PAD_WIDTH);
116 const int RECT_HEIGHT = CELL_HEIGHT - (2 * PAD_HEIGHT);
117
shade_rect(SkCanvas * canvas,sk_sp<SkShader> shader,int cellRow,int cellCol)118 static void shade_rect(SkCanvas* canvas, sk_sp<SkShader> shader, int cellRow, int cellCol) {
119 SkPaint paint;
120 paint.setShader(shader);
121
122 canvas->save();
123 canvas->translate(SkIntToScalar(cellCol * CELL_WIDTH + PAD_WIDTH),
124 SkIntToScalar(cellRow * CELL_HEIGHT + PAD_HEIGHT));
125
126 const SkRect rect = SkRect::MakeWH(SkIntToScalar(RECT_WIDTH), SkIntToScalar(RECT_HEIGHT));
127 canvas->drawRect(rect, paint);
128 canvas->restore();
129 }
130
131 class AnalyticGradientShaderGM : public skiagm::GM {
132 public:
AnalyticGradientShaderGM()133 AnalyticGradientShaderGM() {
134
135 }
136
137 protected:
onShortName()138 SkString onShortName() override {
139 return SkString("analytic_gradients");
140 }
141
onISize()142 SkISize onISize() override {
143 return SkISize::Make(1024, 512);
144 }
145
onDraw(SkCanvas * canvas)146 void onDraw(SkCanvas* canvas) override {
147 const SkPoint points[2] = { SkPoint::Make(0, 0), SkPoint::Make(RECT_WIDTH, 0.0) };
148
149 for (int cellRow = 0; cellRow < NUM_ROWS; cellRow++) {
150 // Each interval has 4 different color counts, one per mode
151 const int* colorCounts = INTERVAL_COLOR_COUNTS[cellRow]; // Has len = 4
152
153 for (int cellCol = 0; cellCol < NUM_COLS; cellCol++) {
154 // create_gradient_points(cellRow, cellCol, points);
155
156 // Get the color count dependent on interval and mode
157 int colorCount = colorCounts[cellCol];
158 // Get the positions given the mode
159 const int* layout = M_POSITIONS[cellCol];
160
161 // Collect positions and colors specific to the interval+mode normalizing the
162 // position based on the interval count (== cellRow+1)
163 SkAutoSTMalloc<4, SkColor> colors(colorCount);
164 SkAutoSTMalloc<4, SkScalar> positions(colorCount);
165 int j = 0;
166 for (int i = 0; i < colorCount; i++) {
167 positions[i] = SkIntToScalar(layout[i]) / (cellRow + 1);
168 colors[i] = COLORS[j % COLOR_COUNT];
169 j++;
170 }
171
172 auto shader = SkGradientShader::MakeLinear(
173 points,
174 colors.get(),
175 positions.get(),
176 colorCount,
177 SkTileMode::kClamp,
178 0,
179 nullptr);
180
181 shade_rect(canvas, shader, cellRow, cellCol);
182 }
183 }
184 }
185
186 private:
187 using INHERITED = skiagm::GM;
188 };
189
190 DEF_GM(return new AnalyticGradientShaderGM;)
191