1 /*
2 * Copyright 2013 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/SkMatrix.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/SkTileMode.h"
19 #include "include/core/SkTypes.h"
20 #include "include/effects/SkGradientShader.h"
21
22 constexpr SkColor gColors[] = {
23 SK_ColorRED, SK_ColorYELLOW
24 };
25
26 // These annoying defines are necessary, because the only other alternative
27 // is to use SkIntToScalar(...) everywhere.
28 constexpr SkScalar sZero = 0;
29 constexpr SkScalar sHalf = SK_ScalarHalf;
30 constexpr SkScalar sOne = SK_Scalar1;
31
32 // These arrays define the gradient stop points
33 // as x1, y1, x2, y2 per gradient to draw.
34 constexpr SkPoint linearPts[][2] = {
35 {{sZero, sZero}, {sOne, sZero}},
36 {{sZero, sZero}, {sZero, sOne}},
37 {{sOne, sZero}, {sZero, sZero}},
38 {{sZero, sOne}, {sZero, sZero}},
39
40 {{sZero, sZero}, {sOne, sOne}},
41 {{sOne, sOne}, {sZero, sZero}},
42 {{sOne, sZero}, {sZero, sOne}},
43 {{sZero, sOne}, {sOne, sZero}}
44 };
45
46 constexpr SkPoint radialPts[][2] = {
47 {{sZero, sHalf}, {sOne, sHalf}},
48 {{sHalf, sZero}, {sHalf, sOne}},
49 {{sOne, sHalf}, {sZero, sHalf}},
50 {{sHalf, sOne}, {sHalf, sZero}},
51
52 {{sZero, sZero}, {sOne, sOne}},
53 {{sOne, sOne}, {sZero, sZero}},
54 {{sOne, sZero}, {sZero, sOne}},
55 {{sZero, sOne}, {sOne, sZero}}
56 };
57
58 // These define the pixels allocated to each gradient image.
59 constexpr SkScalar TESTGRID_X = SkIntToScalar(200);
60 constexpr SkScalar TESTGRID_Y = SkIntToScalar(200);
61
62 constexpr int IMAGES_X = 4; // number of images per row
63
make_linear_gradient(const SkPoint pts[2],const SkMatrix & localMatrix)64 static sk_sp<SkShader> make_linear_gradient(const SkPoint pts[2], const SkMatrix& localMatrix) {
65 return SkGradientShader::MakeLinear(pts, gColors, nullptr, SK_ARRAY_COUNT(gColors),
66 SkTileMode::kClamp, 0, &localMatrix);
67 }
68
make_radial_gradient(const SkPoint pts[2],const SkMatrix & localMatrix)69 static sk_sp<SkShader> make_radial_gradient(const SkPoint pts[2], const SkMatrix& localMatrix) {
70 SkPoint center;
71 center.set(SkScalarAve(pts[0].fX, pts[1].fX),
72 SkScalarAve(pts[0].fY, pts[1].fY));
73 float radius = (center - pts[0]).length();
74 return SkGradientShader::MakeRadial(center, radius, gColors, nullptr, SK_ARRAY_COUNT(gColors),
75 SkTileMode::kClamp, 0, &localMatrix);
76 }
77
draw_gradients(SkCanvas * canvas,sk_sp<SkShader> (* makeShader)(const SkPoint[2],const SkMatrix &),const SkPoint ptsArray[][2],int numImages)78 static void draw_gradients(SkCanvas* canvas,
79 sk_sp<SkShader> (*makeShader)(const SkPoint[2], const SkMatrix&),
80 const SkPoint ptsArray[][2], int numImages) {
81 // Use some nice prime numbers for the rectangle and matrix with
82 // different scaling along the x and y axes (which is the bug this
83 // test addresses, where incorrect order of operations mixed up the axes)
84 SkRect rectGrad = {
85 SkIntToScalar(43), SkIntToScalar(61),
86 SkIntToScalar(181), SkIntToScalar(167) };
87 SkMatrix shaderMat;
88 shaderMat.setScale(rectGrad.width(), rectGrad.height());
89 shaderMat.postTranslate(rectGrad.left(), rectGrad.top());
90
91 canvas->save();
92 for (int i = 0; i < numImages; i++) {
93 // Advance line downwards if necessary.
94 if (i % IMAGES_X == 0 && i != 0) {
95 canvas->restore();
96 canvas->translate(0, TESTGRID_Y);
97 canvas->save();
98 }
99
100 SkPaint paint;
101 paint.setShader(makeShader(*ptsArray, shaderMat));
102 canvas->drawRect(rectGrad, paint);
103
104 // Advance to next position.
105 canvas->translate(TESTGRID_X, 0);
106 ptsArray++;
107 }
108 canvas->restore();
109 }
110
111 DEF_SIMPLE_GM_BG(gradient_matrix, canvas, 800, 800, 0xFFDDDDDD) {
112 draw_gradients(canvas, &make_linear_gradient,
113 linearPts, SK_ARRAY_COUNT(linearPts));
114
115 canvas->translate(0, TESTGRID_Y);
116
117 draw_gradients(canvas, &make_radial_gradient,
118 radialPts, SK_ARRAY_COUNT(radialPts));
119 }
120