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 "gm.h"
9 #include "sk_tool_utils.h"
10 #include "SkArithmeticImageFilter.h"
11 #include "SkCanvas.h"
12 #include "SkColorPriv.h"
13 #include "SkGradientShader.h"
14 #include "SkImage.h"
15 #include "SkImageSource.h"
16 #include "SkShader.h"
17 #include "SkSurface.h"
18
19 #define WW 100
20 #define HH 32
21
make_src()22 static sk_sp<SkImage> make_src() {
23 sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(WW, HH));
24 SkCanvas* canvas = surface->getCanvas();
25
26 SkPaint paint;
27 SkPoint pts[] = { {0, 0}, {SkIntToScalar(WW), SkIntToScalar(HH)} };
28 SkColor colors[] = {
29 SK_ColorTRANSPARENT, SK_ColorGREEN, SK_ColorCYAN,
30 SK_ColorRED, SK_ColorMAGENTA, SK_ColorWHITE,
31 };
32 paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors),
33 SkShader::kClamp_TileMode));
34 canvas->drawPaint(paint);
35 return surface->makeImageSnapshot();
36 }
37
make_dst()38 static sk_sp<SkImage> make_dst() {
39 sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(WW, HH));
40 SkCanvas* canvas = surface->getCanvas();
41
42 SkPaint paint;
43 SkPoint pts[] = { {0, SkIntToScalar(HH)}, {SkIntToScalar(WW), 0} };
44 SkColor colors[] = {
45 SK_ColorBLUE, SK_ColorYELLOW, SK_ColorBLACK, SK_ColorGREEN,
46 sk_tool_utils::color_to_565(SK_ColorGRAY)
47 };
48 paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors),
49 SkShader::kClamp_TileMode));
50 canvas->drawPaint(paint);
51 return surface->makeImageSnapshot();
52 }
53
show_k_text(SkCanvas * canvas,SkScalar x,SkScalar y,const SkScalar k[])54 static void show_k_text(SkCanvas* canvas, SkScalar x, SkScalar y, const SkScalar k[]) {
55 SkPaint paint;
56 paint.setTextSize(SkIntToScalar(24));
57 paint.setAntiAlias(true);
58 sk_tool_utils::set_portable_typeface(&paint);
59 for (int i = 0; i < 4; ++i) {
60 SkString str;
61 str.appendScalar(k[i]);
62 SkScalar width = paint.measureText(str.c_str(), str.size());
63 canvas->drawString(str, x, y + paint.getTextSize(), paint);
64 x += width + SkIntToScalar(10);
65 }
66 }
67
68 class ArithmodeGM : public skiagm::GM {
69 public:
ArithmodeGM()70 ArithmodeGM () {}
71
72 protected:
73
onShortName()74 virtual SkString onShortName() {
75 return SkString("arithmode");
76 }
77
onISize()78 virtual SkISize onISize() { return SkISize::Make(640, 572); }
79
onDraw(SkCanvas * canvas)80 virtual void onDraw(SkCanvas* canvas) {
81 sk_sp<SkImage> src = make_src();
82 sk_sp<SkImage> dst = make_dst();
83 sk_sp<SkImageFilter> srcFilter = SkImageSource::Make(src);
84 sk_sp<SkImageFilter> dstFilter = SkImageSource::Make(dst);
85
86 constexpr SkScalar one = SK_Scalar1;
87 constexpr SkScalar K[] = {
88 0, 0, 0, 0,
89 0, 0, 0, one,
90 0, one, 0, 0,
91 0, 0, one, 0,
92 0, one, one, 0,
93 0, one, -one, 0,
94 0, one/2, one/2, 0,
95 0, one/2, one/2, one/4,
96 0, one/2, one/2, -one/4,
97 one/4, one/2, one/2, 0,
98 -one/4, one/2, one/2, 0,
99 };
100
101 const SkScalar* k = K;
102 const SkScalar* stop = k + SK_ARRAY_COUNT(K);
103 const SkRect rect = SkRect::MakeWH(WW, HH);
104 SkScalar gap = SkIntToScalar(WW + 20);
105 while (k < stop) {
106 {
107 SkAutoCanvasRestore acr(canvas, true);
108 canvas->drawImage(src, 0, 0);
109 canvas->translate(gap, 0);
110 canvas->drawImage(dst, 0, 0);
111 canvas->translate(gap, 0);
112 SkPaint paint;
113 paint.setImageFilter(SkArithmeticImageFilter::Make(k[0], k[1], k[2], k[3], true,
114 dstFilter, srcFilter, nullptr));
115 canvas->saveLayer(&rect, &paint);
116 canvas->restore();
117
118 canvas->translate(gap, 0);
119 show_k_text(canvas, 0, 0, k);
120 }
121
122 k += 4;
123 canvas->translate(0, HH + 12);
124 }
125
126 // Draw two special cases to test enforcePMColor. In these cases, we
127 // draw the dst bitmap twice, the first time it is halved and inverted,
128 // leading to invalid premultiplied colors. If we enforcePMColor, these
129 // invalid values should be clamped, and will not contribute to the
130 // second draw.
131 for (int i = 0; i < 2; i++) {
132 const bool enforcePMColor = (i == 0);
133
134 {
135 SkAutoCanvasRestore acr(canvas, true);
136 canvas->translate(gap, 0);
137 canvas->drawImage(dst, 0, 0);
138 canvas->translate(gap, 0);
139
140 sk_sp<SkImageFilter> bg =
141 SkArithmeticImageFilter::Make(0, 0, -one / 2, 1, enforcePMColor, dstFilter,
142 nullptr, nullptr);
143 SkPaint p;
144 p.setImageFilter(SkArithmeticImageFilter::Make(0, one / 2, -one, 1, true,
145 std::move(bg), dstFilter, nullptr));
146 canvas->saveLayer(&rect, &p);
147 canvas->restore();
148 canvas->translate(gap, 0);
149
150 // Label
151 SkPaint paint;
152 paint.setTextSize(SkIntToScalar(24));
153 paint.setAntiAlias(true);
154 sk_tool_utils::set_portable_typeface(&paint);
155 SkString str(enforcePMColor ? "enforcePM" : "no enforcePM");
156 canvas->drawString(str, 0, paint.getTextSize(), paint);
157 }
158 canvas->translate(0, HH + 12);
159 }
160 }
161
162 private:
163 typedef GM INHERITED;
164 };
165
166 ///////////////////////////////////////////////////////////////////////////////
167
168 DEF_GM( return new ArithmodeGM; )
169