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 "include/core/SkCanvas.h"
9 #include "include/core/SkPaint.h"
10 #include "include/core/SkPath.h"
11 #include "samplecode/Sample.h"
12
13 // ensure that we don't accidentally screw up the bounds when the oval is
14 // fractional, and the impl computes the center and radii, and uses them to
15 // reconstruct the edges of the circle.
16 // see bug# 1504910
test_circlebounds(SkCanvas *)17 static void test_circlebounds(SkCanvas*) {
18 SkRect r = { 1.39999998f, 1, 21.3999996f, 21 };
19 SkPath p;
20 p.addOval(r);
21 SkASSERT(r == p.getBounds());
22 }
23
24 class CircleView : public Sample {
name()25 SkString name() override { return SkString("Circles"); }
26
circle(SkCanvas * canvas,int width,bool aa)27 void circle(SkCanvas* canvas, int width, bool aa) {
28 SkPaint paint;
29
30 paint.setAntiAlias(aa);
31 if (width < 0) {
32 paint.setStyle(SkPaint::kFill_Style);
33 } else {
34 paint.setStyle(SkPaint::kStroke_Style);
35 paint.setStrokeWidth(SkIntToScalar(width));
36 }
37 canvas->drawCircle(0, 0, 9.0f, paint);
38 if (false) { // avoid bit rot, suppress warning
39 test_circlebounds(canvas);
40 }
41 }
42
drawSix(SkCanvas * canvas,SkScalar dx,SkScalar dy)43 void drawSix(SkCanvas* canvas, SkScalar dx, SkScalar dy) {
44 for (int width = -1; width <= 1; width++) {
45 canvas->save();
46 circle(canvas, width, false);
47 canvas->translate(0, dy);
48 circle(canvas, width, true);
49 canvas->restore();
50 canvas->translate(dx, 0);
51 }
52 }
53
make_poly(SkPath * path,int n)54 static void make_poly(SkPath* path, int n) {
55 if (n <= 0) {
56 return;
57 }
58 path->incReserve(n + 1);
59 path->moveTo(SK_Scalar1, 0);
60 SkScalar step = SK_ScalarPI * 2 / n;
61 SkScalar angle = 0;
62 for (int i = 1; i < n; i++) {
63 angle += step;
64 path->lineTo(SkScalarCos(angle), SkScalarSin(angle));
65 }
66 path->close();
67 }
68
onDrawContent(SkCanvas * canvas)69 void onDrawContent(SkCanvas* canvas) override {
70 SkPaint paint;
71 paint.setAntiAlias(true);
72 paint.setStyle(SkPaint::kStroke_Style);
73 SkMatrix matrix;
74 matrix.setScale(SkIntToScalar(100), SkIntToScalar(100));
75 matrix.postTranslate(SkIntToScalar(200), SkIntToScalar(200));
76 canvas->concat(matrix);
77 for (int n = 3; n < 20; n++) {
78 SkPath path;
79 make_poly(&path, n);
80 SkAutoCanvasRestore acr(canvas, true);
81 canvas->rotate(SkIntToScalar(10) * (n - 3));
82 canvas->translate(-SK_Scalar1, 0);
83 canvas->drawPath(path, paint);
84 }
85 }
86 };
87
88 DEF_SAMPLE( return new CircleView(); )
89