GradientTest.cpp revision 9c0b02a557e9be663a0eb07519e1b6a61a6c3df2 
1/*
2 * Copyright 2011 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 "SkCanvas.h"
9#include "SkColorPriv.h"
10#include "SkColorShader.h"
11#include "SkGradientShader.h"
12#include "SkShader.h"
13#include "SkSurface.h"
14#include "SkTemplates.h"
15#include "Test.h"
16
17// https://code.google.com/p/chromium/issues/detail?id=448299
18// Giant (inverse) matrix causes overflow when converting/computing using 32.32
19// Before the fix, we would assert (and then crash).
20static void test_big_grad(skiatest::Reporter* reporter) {
21    const SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
22    const SkPoint pts[] = {{ 15, 14.7112684f }, { 0.709064007f, 12.6108112f }};
23    SkShader* s = SkGradientShader::CreateLinear(pts, colors, nullptr, 2, SkShader::kClamp_TileMode);
24    SkPaint paint;
25    paint.setShader(s)->unref();
26
27    SkBitmap bm;
28    bm.allocN32Pixels(2000, 1);
29    SkCanvas c(bm);
30
31    const SkScalar affine[] = {
32        1.06608627e-06f, 4.26434525e-07f, 6.2855f, 2.6611f, 273.4393f, 244.0046f
33    };
34    SkMatrix matrix;
35    matrix.setAffine(affine);
36    c.concat(matrix);
37
38    c.drawPaint(paint);
39}
40
41struct GradRec {
42    int             fColorCount;
43    const SkColor*  fColors;
44    const SkScalar* fPos;
45    const SkPoint*  fPoint;   // 2
46    const SkScalar* fRadius; // 2
47    SkShader::TileMode fTileMode;
48
49    void gradCheck(skiatest::Reporter* reporter, SkShader* shader,
50                   SkShader::GradientInfo* info,
51                   SkShader::GradientType gt) const {
52        SkAutoTMalloc<SkColor> colorStorage(fColorCount);
53        SkAutoTMalloc<SkScalar> posStorage(fColorCount);
54
55        info->fColorCount = fColorCount;
56        info->fColors = colorStorage;
57        info->fColorOffsets = posStorage.get();
58        REPORTER_ASSERT(reporter, shader->asAGradient(info) == gt);
59
60        REPORTER_ASSERT(reporter, info->fColorCount == fColorCount);
61        REPORTER_ASSERT(reporter,
62                        !memcmp(info->fColors, fColors, fColorCount * sizeof(SkColor)));
63        REPORTER_ASSERT(reporter,
64                        !memcmp(info->fColorOffsets, fPos, fColorCount * sizeof(SkScalar)));
65        REPORTER_ASSERT(reporter, fTileMode == info->fTileMode);
66    }
67};
68
69
70static void none_gradproc(skiatest::Reporter* reporter, const GradRec&) {
71    SkAutoTUnref<SkShader> s(SkShader::CreateEmptyShader());
72    REPORTER_ASSERT(reporter, SkShader::kNone_GradientType == s->asAGradient(nullptr));
73}
74
75static void color_gradproc(skiatest::Reporter* reporter, const GradRec& rec) {
76    SkAutoTUnref<SkShader> s(new SkColorShader(rec.fColors[0]));
77    REPORTER_ASSERT(reporter, SkShader::kColor_GradientType == s->asAGradient(nullptr));
78
79    SkShader::GradientInfo info;
80    info.fColors = nullptr;
81    info.fColorCount = 0;
82    s->asAGradient(&info);
83    REPORTER_ASSERT(reporter, 1 == info.fColorCount);
84}
85
86static void linear_gradproc(skiatest::Reporter* reporter, const GradRec& rec) {
87    SkAutoTUnref<SkShader> s(SkGradientShader::CreateLinear(rec.fPoint,
88                                                            rec.fColors,
89                                                            rec.fPos,
90                                                            rec.fColorCount,
91                                                            rec.fTileMode));
92
93    SkShader::GradientInfo info;
94    rec.gradCheck(reporter, s, &info, SkShader::kLinear_GradientType);
95    REPORTER_ASSERT(reporter, !memcmp(info.fPoint, rec.fPoint, 2 * sizeof(SkPoint)));
96}
97
98static void radial_gradproc(skiatest::Reporter* reporter, const GradRec& rec) {
99    SkAutoTUnref<SkShader> s(SkGradientShader::CreateRadial(rec.fPoint[0],
100                                                            rec.fRadius[0],
101                                                            rec.fColors,
102                                                            rec.fPos,
103                                                            rec.fColorCount,
104                                                            rec.fTileMode));
105
106    SkShader::GradientInfo info;
107    rec.gradCheck(reporter, s, &info, SkShader::kRadial_GradientType);
108    REPORTER_ASSERT(reporter, info.fPoint[0] == rec.fPoint[0]);
109    REPORTER_ASSERT(reporter, info.fRadius[0] == rec.fRadius[0]);
110}
111
112static void sweep_gradproc(skiatest::Reporter* reporter, const GradRec& rec) {
113    SkAutoTUnref<SkShader> s(SkGradientShader::CreateSweep(rec.fPoint[0].fX,
114                                                           rec.fPoint[0].fY,
115                                                           rec.fColors,
116                                                           rec.fPos,
117                                                           rec.fColorCount));
118
119    SkShader::GradientInfo info;
120    rec.gradCheck(reporter, s, &info, SkShader::kSweep_GradientType);
121    REPORTER_ASSERT(reporter, info.fPoint[0] == rec.fPoint[0]);
122}
123
124static void conical_gradproc(skiatest::Reporter* reporter, const GradRec& rec) {
125    SkAutoTUnref<SkShader> s(SkGradientShader::CreateTwoPointConical(rec.fPoint[0],
126                                                             rec.fRadius[0],
127                                                             rec.fPoint[1],
128                                                             rec.fRadius[1],
129                                                             rec.fColors,
130                                                             rec.fPos,
131                                                             rec.fColorCount,
132                                                             rec.fTileMode));
133
134    SkShader::GradientInfo info;
135    rec.gradCheck(reporter, s, &info, SkShader::kConical_GradientType);
136    REPORTER_ASSERT(reporter, !memcmp(info.fPoint, rec.fPoint, 2 * sizeof(SkPoint)));
137    REPORTER_ASSERT(reporter, !memcmp(info.fRadius, rec.fRadius, 2 * sizeof(SkScalar)));
138}
139
140// Ensure that repeated color gradients behave like drawing a single color
141static void TestConstantGradient(skiatest::Reporter*) {
142    const SkPoint pts[] = {
143        { 0, 0 },
144        { SkIntToScalar(10), 0 }
145    };
146    SkColor colors[] = { SK_ColorBLUE, SK_ColorBLUE };
147    const SkScalar pos[] = { 0, SK_Scalar1 };
148    SkAutoTUnref<SkShader> s(SkGradientShader::CreateLinear(pts,
149                                                            colors,
150                                                            pos,
151                                                            2,
152                                                            SkShader::kClamp_TileMode));
153    SkBitmap outBitmap;
154    outBitmap.allocN32Pixels(10, 1);
155    SkPaint paint;
156    paint.setShader(s.get());
157    SkCanvas canvas(outBitmap);
158    canvas.drawPaint(paint);
159    SkAutoLockPixels alp(outBitmap);
160    for (int i = 0; i < 10; i++) {
161        // The following is commented out because it currently fails
162        // Related bug: https://code.google.com/p/skia/issues/detail?id=1098
163
164        // REPORTER_ASSERT(reporter, SK_ColorBLUE == outBitmap.getColor(i, 0));
165    }
166}
167
168typedef void (*GradProc)(skiatest::Reporter* reporter, const GradRec&);
169
170static void TestGradientShaders(skiatest::Reporter* reporter) {
171    static const SkColor gColors[] = { SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE };
172    static const SkScalar gPos[] = { 0, SK_ScalarHalf, SK_Scalar1 };
173    static const SkPoint gPts[] = {
174        { 0, 0 },
175        { SkIntToScalar(10), SkIntToScalar(20) }
176    };
177    static const SkScalar gRad[] = { SkIntToScalar(1), SkIntToScalar(2) };
178
179    GradRec rec;
180    rec.fColorCount = SK_ARRAY_COUNT(gColors);
181    rec.fColors = gColors;
182    rec.fPos = gPos;
183    rec.fPoint = gPts;
184    rec.fRadius = gRad;
185    rec.fTileMode = SkShader::kClamp_TileMode;
186
187    static const GradProc gProcs[] = {
188        none_gradproc,
189        color_gradproc,
190        linear_gradproc,
191        radial_gradproc,
192        sweep_gradproc,
193        conical_gradproc,
194    };
195
196    for (size_t i = 0; i < SK_ARRAY_COUNT(gProcs); ++i) {
197        gProcs[i](reporter, rec);
198    }
199}
200
201static void test_nearly_vertical(skiatest::Reporter* reporter) {
202    SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(200, 200));
203
204    const SkPoint pts[] = {{ 100, 50 }, { 100.0001f, 50000 }};
205    const SkColor colors[] = { SK_ColorBLACK, SK_ColorWHITE };
206    const SkScalar pos[] = { 0, 1 };
207    SkAutoTUnref<SkShader> gradient(
208        SkGradientShader::CreateLinear(pts, colors, pos, 2, SkShader::kClamp_TileMode));
209
210    SkPaint paint;
211    paint.setShader(gradient);
212
213    surface->getCanvas()->drawPaint(paint);
214}
215
216// A linear gradient interval can, due to numerical imprecision (likely in the divide)
217// finish an interval with the final fx not landing outside of [p0...p1].
218// The old code had an assert which this test triggered.
219// We now explicitly clamp the resulting fx value.
220static void test_linear_fuzz(skiatest::Reporter* reporter) {
221    SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(1300, 630));
222
223    const SkPoint pts[] = {{ 179.5f, -179.5f }, { 1074.5f, 715.5f }};
224    const SkColor colors[] = { SK_ColorBLACK, SK_ColorWHITE, SK_ColorBLACK, SK_ColorWHITE };
225    const SkScalar pos[] = {0, 0.200000003f, 0.800000012f, 1 };
226
227
228    SkAutoTUnref<SkShader> gradient(
229                   SkGradientShader::CreateLinear(pts, colors, pos, 4, SkShader::kClamp_TileMode));
230
231    SkPaint paint;
232    paint.setShader(gradient);
233    SkRect r = {0, 83, 1254, 620};
234    surface->getCanvas()->drawRect(r, paint);
235}
236
237// https://bugs.chromium.org/p/skia/issues/detail?id=5023
238// We should still shade pixels for which the radius is exactly 0.
239static void test_two_point_conical_zero_radius(skiatest::Reporter* reporter) {
240    SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(5, 5));
241    surface->getCanvas()->clear(SK_ColorRED);
242
243    const SkColor colors[] = { SK_ColorGREEN, SK_ColorBLUE };
244    SkAutoTUnref<SkShader> shader(SkGradientShader::CreateTwoPointConical(
245        SkPoint::Make(2.5f, 2.5f), 0,
246        SkPoint::Make(3.0f, 3.0f), 10,
247        colors, nullptr, SK_ARRAY_COUNT(colors), SkShader::kClamp_TileMode));
248    SkPaint p;
249    p.setShader(shader);
250    surface->getCanvas()->drawPaint(p);
251
252    // r == 0 for the center pixel.
253    // verify that we draw it (no red bleed)
254    SkPMColor centerPMColor;
255    surface->readPixels(SkImageInfo::MakeN32Premul(1, 1), &centerPMColor, sizeof(SkPMColor), 2, 2);
256    REPORTER_ASSERT(reporter, SkGetPackedR32(centerPMColor) == 0);
257}
258
259DEF_TEST(Gradient, reporter) {
260    TestGradientShaders(reporter);
261    TestConstantGradient(reporter);
262    test_big_grad(reporter);
263    test_nearly_vertical(reporter);
264    test_linear_fuzz(reporter);
265    test_two_point_conical_zero_radius(reporter);
266}
267