1 /*
2  * Copyright 2014 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 "SkPath.h"
10 #include "SkScan.h"
11 
12 #define W   800
13 #define H   800
14 
15 class AnalyticAntiAliasConvexGM : public skiagm::GM {
16 public:
AnalyticAntiAliasConvexGM()17     AnalyticAntiAliasConvexGM() {}
18 
19 protected:
20 
onShortName()21     SkString onShortName() override {
22         return SkString("analytic_antialias_convex");
23     }
24 
onISize()25     SkISize onISize() override {
26         return SkISize::Make(W, H);
27     }
28 
onDraw(SkCanvas * canvas)29     void onDraw(SkCanvas* canvas) override {
30         SkPaint p;
31         p.setColor(SK_ColorRED);
32         p.setAntiAlias(true);
33 
34         canvas->clear(0xFFFFFFFF);
35 
36         canvas->save();
37 
38         SkScalar y = 0;
39 
40         canvas->translate(0, y);
41         canvas->rotate(1);
42         canvas->drawRect({ 20, 20, 200, 200 }, p);
43         canvas->restore();
44 
45         y += 200;
46 
47         canvas->translate(0, y);
48         canvas->rotate(1);
49         canvas->drawRect({ 20, 20, 20.2f, 200 }, p);
50         canvas->drawRect({ 20, 200, 200, 200.1f }, p);
51         canvas->drawCircle(100, 100, 30, p);
52         canvas->restore();
53 
54         // The following path is empty but it'll reveal bug chrome:662914
55         SkPath path;
56         path.moveTo(SkBits2Float(0x429b9d5c), SkBits2Float(0x4367a041));  // 77.8073f, 231.626f
57         // 77.8075f, 231.626f, 77.8074f, 231.625f, 77.8073f, 231.625f
58         path.cubicTo(SkBits2Float(0x429b9d71), SkBits2Float(0x4367a022),
59                 SkBits2Float(0x429b9d64), SkBits2Float(0x4367a009),
60                 SkBits2Float(0x429b9d50), SkBits2Float(0x43679ff2));
61         path.lineTo(SkBits2Float(0x429b9d5c), SkBits2Float(0x4367a041));  // 77.8073f, 231.626f
62         path.close();
63         canvas->drawPath(path, p);
64 
65         // The following path reveals a subtle SkAnalyticQuadraticEdge::updateQuadratic bug:
66         // we should not use any snapped y for the intermediate values whose error may accumulate;
67         // snapping should only be allowed once before updateLine.
68         path.reset();
69         path.moveTo(SkBits2Float(0x434ba71e), SkBits2Float(0x438a06d0));  // 203.653f, 276.053f
70         path.lineTo(SkBits2Float(0x43492a74), SkBits2Float(0x4396d70d));  // 201.166f, 301.68f
71         // 200.921f, 304.207f, 196.939f, 303.82f, 0.707107f
72         path.conicTo(SkBits2Float(0x4348ebaf), SkBits2Float(0x43981a75),
73                 SkBits2Float(0x4344f079), SkBits2Float(0x4397e900), SkBits2Float(0x3f3504f3));
74         path.close();
75         // Manually setting convexity is required. Otherwise, this path will be considered concave.
76         path.setConvexity(SkPath::kConvex_Convexity);
77         canvas->drawPath(path, p);
78     }
79 
80 private:
81     typedef skiagm::GM INHERITED;
82 };
83 
84 class AnalyticAntiAliasGeneralGM : public skiagm::GM {
85 public:
AnalyticAntiAliasGeneralGM()86     AnalyticAntiAliasGeneralGM() {}
87 
88 protected:
89 
onShortName()90     SkString onShortName() override {
91         return SkString("analytic_antialias_general");
92     }
93 
onISize()94     SkISize onISize() override {
95         return SkISize::Make(W, H);
96     }
97 
onDraw(SkCanvas * canvas)98     void onDraw(SkCanvas* canvas) override {
99         SkPaint p;
100         p.setColor(SK_ColorRED);
101         p.setAntiAlias(true);
102 
103         canvas->clear(0xFFFFFFFF);
104 
105         canvas->save();
106         canvas->rotate(1);
107         const SkScalar R = 115.2f, C = 128.0f;
108         SkPath path;
109         path.moveTo(C + R, C);
110         for (int i = 1; i < 8; ++i) {
111             SkScalar a = 2.6927937f * i;
112             SkScalar cosine;
113             SkScalar sine = SkScalarSinCos(a, &cosine);
114             path.lineTo(C + R * cosine, C + R * sine);
115         }
116         canvas->drawPath(path, p);
117         canvas->restore();
118 
119         canvas->save();
120         canvas->translate(200, 0);
121         canvas->rotate(1);
122         p.setStyle(SkPaint::kStroke_Style);
123         p.setStrokeWidth(5);
124         canvas->drawPath(path, p);
125         canvas->restore();
126 
127 
128         // The following two paths test if we correctly cumulates the alpha on the middle pixel
129         // column where the left rect and the right rect abut.
130         p.setStyle(SkPaint::kFill_Style);
131         canvas->translate(0, 300);
132         path.reset();
133         path.addRect({20, 20, 100.4999f, 100});
134         path.addRect({100.5001f, 20, 200, 100});
135         canvas->drawPath(path, p);
136 
137         canvas->translate(300, 0);
138         path.reset();
139         path.addRect({20, 20, 100.1f, 100});
140         path.addRect({100.9f, 20, 200, 100});
141         canvas->drawPath(path, p);
142     }
143 
144 private:
145     typedef skiagm::GM INHERITED;
146 };
147 
148 class AnalyticAntiAliasInverseGM : public skiagm::GM {
149 public:
AnalyticAntiAliasInverseGM()150     AnalyticAntiAliasInverseGM() {}
151 
152 protected:
153 
onShortName()154     SkString onShortName() override {
155         return SkString("analytic_antialias_inverse");
156     }
157 
onISize()158     SkISize onISize() override {
159         return SkISize::Make(W, H);
160     }
161 
onDraw(SkCanvas * canvas)162     void onDraw(SkCanvas* canvas) override {
163         SkPaint p;
164         p.setColor(SK_ColorRED);
165         p.setAntiAlias(true);
166 
167         canvas->save();
168 
169         SkPath path;
170         path.addCircle(100, 100, 30);
171         path.setFillType(SkPath::kInverseWinding_FillType);
172         canvas->drawPath(path, p);
173         canvas->restore();
174     }
175 
176 private:
177     typedef skiagm::GM INHERITED;
178 };
179 
180 DEF_GM( return new AnalyticAntiAliasConvexGM; )
181 DEF_GM( return new AnalyticAntiAliasGeneralGM; )
182 DEF_GM( return new AnalyticAntiAliasInverseGM; )
183