1 /*
2  * Copyright 2016 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 "SkDashPathEffect.h"
11 
12 int dash1[] = { 1, 1 };
13 int dash2[] = { 1, 3 };
14 int dash3[] = { 1, 1, 3, 3 };
15 int dash4[] = { 1, 3, 2, 4 };
16 
17 struct DashExample {
18     int* pattern;
19     int length;
20 } dashExamples[] = {
21     { dash1, SK_ARRAY_COUNT(dash1) },
22     { dash2, SK_ARRAY_COUNT(dash2) },
23     { dash3, SK_ARRAY_COUNT(dash3) },
24     { dash4, SK_ARRAY_COUNT(dash4) }
25 };
26 
27 DEF_SIMPLE_GM(dashcircle, canvas, 900, 1200) {
28     SkPaint refPaint;
29     refPaint.setAntiAlias(true);
30     refPaint.setColor(0xFFbf3f7f);
31     refPaint.setStyle(SkPaint::kStroke_Style);
32     refPaint.setStrokeWidth(1);
33     const SkScalar radius = 125;
34     SkRect oval = SkRect::MakeLTRB(-radius - 20, -radius - 20, radius + 20, radius + 20);
35     SkPath circle;
36     circle.addCircle(0, 0, radius);
37     SkScalar circumference = radius * SK_ScalarPI * 2;
38     int wedges[] = { 6, 12, 36 };
39     canvas->translate(radius + 20, radius + 20);
40     for (int wedge : wedges) {
41         SkScalar arcLength = 360.f / wedge;
42         canvas->save();
43         for (const DashExample& dashExample : dashExamples) {
44             SkPath refPath;
45             int dashUnits = 0;
46             for (int index = 0; index < dashExample.length; ++index) {
47                 dashUnits += dashExample.pattern[index];
48             }
49             SkScalar unitLength = arcLength / dashUnits;
50             SkScalar angle = 0;
51             for (int index = 0; index < wedge; ++index) {
52                 for (int i2 = 0; i2 < dashExample.length; i2 += 2) {
53                     SkScalar span = dashExample.pattern[i2] * unitLength;
54                     refPath.moveTo(0, 0);
55                     refPath.arcTo(oval, angle, span, false);
56                     refPath.close();
57                     angle += span + (dashExample.pattern[i2 + 1]) * unitLength;
58                 }
59             }
60             canvas->drawPath(refPath, refPaint);
61             SkPaint p;
62             p.setAntiAlias(true);
63             p.setStyle(SkPaint::kStroke_Style);
64             p.setStrokeWidth(10);
65             SkScalar intervals[4];
66             int intervalCount = dashExample.length;
67             SkScalar dashLength = circumference / wedge / dashUnits;
68             for (int index = 0; index < dashExample.length; ++index) {
69                 intervals[index] = dashExample.pattern[index] * dashLength;
70             }
71             p.setPathEffect(SkDashPathEffect::Create(intervals, intervalCount, 0))->unref();
72             canvas->drawPath(circle, p);
73             canvas->translate(0, radius * 2 + 50);
74         }
75         canvas->restore();
76         canvas->translate(radius * 2  + 50, 0);
77     }
78 }
79