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 <SkFont.h>
9 #include "gm.h"
10 #include "sk_tool_utils.h"
11 #include "SkArithmeticImageFilter.h"
12 #include "SkCanvas.h"
13 #include "SkColorPriv.h"
14 #include "SkGradientShader.h"
15 #include "SkImage.h"
16 #include "SkImageSource.h"
17 #include "SkShader.h"
18 #include "SkSurface.h"
19
20 #define WW 100
21 #define HH 32
22
make_src()23 static sk_sp<SkImage> make_src() {
24 sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(WW, HH));
25 SkCanvas* canvas = surface->getCanvas();
26
27 SkPaint paint;
28 SkPoint pts[] = { {0, 0}, {SkIntToScalar(WW), SkIntToScalar(HH)} };
29 SkColor colors[] = {
30 SK_ColorTRANSPARENT, SK_ColorGREEN, SK_ColorCYAN,
31 SK_ColorRED, SK_ColorMAGENTA, SK_ColorWHITE,
32 };
33 paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors),
34 SkShader::kClamp_TileMode));
35 canvas->drawPaint(paint);
36 return surface->makeImageSnapshot();
37 }
38
make_dst()39 static sk_sp<SkImage> make_dst() {
40 sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(WW, HH));
41 SkCanvas* canvas = surface->getCanvas();
42
43 SkPaint paint;
44 SkPoint pts[] = { {0, SkIntToScalar(HH)}, {SkIntToScalar(WW), 0} };
45 SkColor colors[] = {
46 SK_ColorBLUE, SK_ColorYELLOW, SK_ColorBLACK, SK_ColorGREEN,
47 SK_ColorGRAY,
48 };
49 paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors),
50 SkShader::kClamp_TileMode));
51 canvas->drawPaint(paint);
52 return surface->makeImageSnapshot();
53 }
54
show_k_text(SkCanvas * canvas,SkScalar x,SkScalar y,const SkScalar k[])55 static void show_k_text(SkCanvas* canvas, SkScalar x, SkScalar y, const SkScalar k[]) {
56 SkFont font(sk_tool_utils::create_portable_typeface(), 24);
57 font.setEdging(SkFont::Edging::kAntiAlias);
58 SkPaint paint;
59 paint.setAntiAlias(true);
60 for (int i = 0; i < 4; ++i) {
61 SkString str;
62 str.appendScalar(k[i]);
63 SkScalar width = font.measureText(str.c_str(), str.size(), kUTF8_SkTextEncoding);
64 canvas->drawString(str, x, y + font.getSize(), font, paint);
65 x += width + SkIntToScalar(10);
66 }
67 }
68
69 class ArithmodeGM : public skiagm::GM {
70 public:
ArithmodeGM()71 ArithmodeGM () {}
72
73 protected:
74
onShortName()75 virtual SkString onShortName() {
76 return SkString("arithmode");
77 }
78
onISize()79 virtual SkISize onISize() { return SkISize::Make(640, 572); }
80
onDraw(SkCanvas * canvas)81 virtual void onDraw(SkCanvas* canvas) {
82 sk_sp<SkImage> src = make_src();
83 sk_sp<SkImage> dst = make_dst();
84 sk_sp<SkImageFilter> srcFilter = SkImageSource::Make(src);
85 sk_sp<SkImageFilter> dstFilter = SkImageSource::Make(dst);
86
87 constexpr SkScalar one = SK_Scalar1;
88 constexpr SkScalar K[] = {
89 0, 0, 0, 0,
90 0, 0, 0, one,
91 0, one, 0, 0,
92 0, 0, one, 0,
93 0, one, one, 0,
94 0, one, -one, 0,
95 0, one/2, one/2, 0,
96 0, one/2, one/2, one/4,
97 0, one/2, one/2, -one/4,
98 one/4, one/2, one/2, 0,
99 -one/4, one/2, one/2, 0,
100 };
101
102 const SkScalar* k = K;
103 const SkScalar* stop = k + SK_ARRAY_COUNT(K);
104 const SkRect rect = SkRect::MakeWH(WW, HH);
105 SkScalar gap = SkIntToScalar(WW + 20);
106 while (k < stop) {
107 {
108 SkAutoCanvasRestore acr(canvas, true);
109 canvas->drawImage(src, 0, 0);
110 canvas->translate(gap, 0);
111 canvas->drawImage(dst, 0, 0);
112 canvas->translate(gap, 0);
113 SkPaint paint;
114 paint.setImageFilter(SkArithmeticImageFilter::Make(k[0], k[1], k[2], k[3], true,
115 dstFilter, srcFilter, nullptr));
116 canvas->saveLayer(&rect, &paint);
117 canvas->restore();
118
119 canvas->translate(gap, 0);
120 show_k_text(canvas, 0, 0, k);
121 }
122
123 k += 4;
124 canvas->translate(0, HH + 12);
125 }
126
127 // Draw two special cases to test enforcePMColor. In these cases, we
128 // draw the dst bitmap twice, the first time it is halved and inverted,
129 // leading to invalid premultiplied colors. If we enforcePMColor, these
130 // invalid values should be clamped, and will not contribute to the
131 // second draw.
132 for (int i = 0; i < 2; i++) {
133 const bool enforcePMColor = (i == 0);
134
135 {
136 SkAutoCanvasRestore acr(canvas, true);
137 canvas->translate(gap, 0);
138 canvas->drawImage(dst, 0, 0);
139 canvas->translate(gap, 0);
140
141 sk_sp<SkImageFilter> bg =
142 SkArithmeticImageFilter::Make(0, 0, -one / 2, 1, enforcePMColor, dstFilter,
143 nullptr, nullptr);
144 SkPaint p;
145 p.setImageFilter(SkArithmeticImageFilter::Make(0, one / 2, -one, 1, true,
146 std::move(bg), dstFilter, nullptr));
147 canvas->saveLayer(&rect, &p);
148 canvas->restore();
149 canvas->translate(gap, 0);
150
151 // Label
152 SkFont font(sk_tool_utils::create_portable_typeface(), 24);
153 SkString str(enforcePMColor ? "enforcePM" : "no enforcePM");
154 canvas->drawString(str, 0, font.getSize(), font, SkPaint());
155 }
156 canvas->translate(0, HH + 12);
157 }
158 }
159
160 private:
161 typedef GM INHERITED;
162 };
163
164 ///////////////////////////////////////////////////////////////////////////////
165
166 DEF_GM( return new ArithmodeGM; )
167