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/gm.h"
9 #include "include/core/SkCanvas.h"
10 #include "include/core/SkColor.h"
11 #include "include/core/SkFont.h"
12 #include "include/core/SkFontTypes.h"
13 #include "include/core/SkImage.h"
14 #include "include/core/SkImageFilter.h"
15 #include "include/core/SkPaint.h"
16 #include "include/core/SkPoint.h"
17 #include "include/core/SkRect.h"
18 #include "include/core/SkRefCnt.h"
19 #include "include/core/SkScalar.h"
20 #include "include/core/SkShader.h"
21 #include "include/core/SkSize.h"
22 #include "include/core/SkString.h"
23 #include "include/core/SkSurface.h"
24 #include "include/core/SkTileMode.h"
25 #include "include/core/SkTypeface.h"
26 #include "include/core/SkTypes.h"
27 #include "include/effects/SkGradientShader.h"
28 #include "include/effects/SkImageFilters.h"
29 #include "tools/ToolUtils.h"
30
31 #include <utility>
32
33 #define WW 100
34 #define HH 32
35
make_src()36 static sk_sp<SkImage> make_src() {
37 sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(WW, HH));
38 SkCanvas* canvas = surface->getCanvas();
39
40 SkPaint paint;
41 SkPoint pts[] = { {0, 0}, {SkIntToScalar(WW), SkIntToScalar(HH)} };
42 SkColor colors[] = {
43 SK_ColorTRANSPARENT, SK_ColorGREEN, SK_ColorCYAN,
44 SK_ColorRED, SK_ColorMAGENTA, SK_ColorWHITE,
45 };
46 paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors),
47 SkTileMode::kClamp));
48 canvas->drawPaint(paint);
49 return surface->makeImageSnapshot();
50 }
51
make_dst()52 static sk_sp<SkImage> make_dst() {
53 sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(WW, HH));
54 SkCanvas* canvas = surface->getCanvas();
55
56 SkPaint paint;
57 SkPoint pts[] = { {0, SkIntToScalar(HH)}, {SkIntToScalar(WW), 0} };
58 SkColor colors[] = {
59 SK_ColorBLUE, SK_ColorYELLOW, SK_ColorBLACK, SK_ColorGREEN,
60 SK_ColorGRAY,
61 };
62 paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors),
63 SkTileMode::kClamp));
64 canvas->drawPaint(paint);
65 return surface->makeImageSnapshot();
66 }
67
show_k_text(SkCanvas * canvas,SkScalar x,SkScalar y,const SkScalar k[])68 static void show_k_text(SkCanvas* canvas, SkScalar x, SkScalar y, const SkScalar k[]) {
69 SkFont font(ToolUtils::create_portable_typeface(), 24);
70 font.setEdging(SkFont::Edging::kAntiAlias);
71 SkPaint paint;
72 paint.setAntiAlias(true);
73 for (int i = 0; i < 4; ++i) {
74 SkString str;
75 str.appendScalar(k[i]);
76 SkScalar width = font.measureText(str.c_str(), str.size(), SkTextEncoding::kUTF8);
77 canvas->drawString(str, x, y + font.getSize(), font, paint);
78 x += width + SkIntToScalar(10);
79 }
80 }
81
82 class ArithmodeGM : public skiagm::GM {
onShortName()83 SkString onShortName() override { return SkString("arithmode"); }
84
onISize()85 SkISize onISize() override { return {640, 572}; }
86
onDraw(SkCanvas * canvas)87 void onDraw(SkCanvas* canvas) override {
88 sk_sp<SkImage> src = make_src();
89 sk_sp<SkImage> dst = make_dst();
90 sk_sp<SkImageFilter> srcFilter = SkImageFilters::Image(src);
91 sk_sp<SkImageFilter> dstFilter = SkImageFilters::Image(dst);
92
93 constexpr SkScalar one = SK_Scalar1;
94 constexpr SkScalar K[] = {
95 0, 0, 0, 0,
96 0, 0, 0, one,
97 0, one, 0, 0,
98 0, 0, one, 0,
99 0, one, one, 0,
100 0, one, -one, 0,
101 0, one/2, one/2, 0,
102 0, one/2, one/2, one/4,
103 0, one/2, one/2, -one/4,
104 one/4, one/2, one/2, 0,
105 -one/4, one/2, one/2, 0,
106 };
107
108 const SkScalar* k = K;
109 const SkScalar* stop = k + SK_ARRAY_COUNT(K);
110 const SkRect rect = SkRect::MakeWH(WW, HH);
111 SkScalar gap = SkIntToScalar(WW + 20);
112 while (k < stop) {
113 {
114 SkAutoCanvasRestore acr(canvas, true);
115 canvas->drawImage(src, 0, 0);
116 canvas->translate(gap, 0);
117 canvas->drawImage(dst, 0, 0);
118 canvas->translate(gap, 0);
119 SkPaint paint;
120 paint.setImageFilter(SkImageFilters::Arithmetic(k[0], k[1], k[2], k[3], true,
121 dstFilter, srcFilter, nullptr));
122 canvas->saveLayer(&rect, &paint);
123 canvas->restore();
124
125 canvas->translate(gap, 0);
126 show_k_text(canvas, 0, 0, k);
127 }
128
129 k += 4;
130 canvas->translate(0, HH + 12);
131 }
132
133 // Draw two special cases to test enforcePMColor. In these cases, we
134 // draw the dst bitmap twice, the first time it is halved and inverted,
135 // leading to invalid premultiplied colors. If we enforcePMColor, these
136 // invalid values should be clamped, and will not contribute to the
137 // second draw.
138 for (int i = 0; i < 2; i++) {
139 const bool enforcePMColor = (i == 0);
140
141 {
142 SkAutoCanvasRestore acr(canvas, true);
143 canvas->translate(gap, 0);
144 canvas->drawImage(dst, 0, 0);
145 canvas->translate(gap, 0);
146
147 sk_sp<SkImageFilter> bg =
148 SkImageFilters::Arithmetic(0, 0, -one / 2, 1, enforcePMColor, dstFilter,
149 nullptr, nullptr);
150 SkPaint p;
151 p.setImageFilter(SkImageFilters::Arithmetic(0, one / 2, -one, 1, true,
152 std::move(bg), dstFilter, nullptr));
153 canvas->saveLayer(&rect, &p);
154 canvas->restore();
155 canvas->translate(gap, 0);
156
157 // Label
158 SkFont font(ToolUtils::create_portable_typeface(), 24);
159 SkString str(enforcePMColor ? "enforcePM" : "no enforcePM");
160 canvas->drawString(str, 0, font.getSize(), font, SkPaint());
161 }
162 canvas->translate(0, HH + 12);
163 }
164 }
165
166 private:
167 using INHERITED = GM;
168 };
169
170 ///////////////////////////////////////////////////////////////////////////////
171
172 DEF_GM( return new ArithmodeGM; )
173