xref: /aosp_15_r20/external/skia/docs/examples/Miter_Limit.cpp (revision c8dee2aa9b3f27cf6c858bd81872bdeb2c07ed17)
1*c8dee2aaSAndroid Build Coastguard Worker // Copyright 2019 Google LLC.
2*c8dee2aaSAndroid Build Coastguard Worker // Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
3*c8dee2aaSAndroid Build Coastguard Worker #include "tools/fiddle/examples.h"
4*c8dee2aaSAndroid Build Coastguard Worker REG_FIDDLE(Miter_Limit, 384, 170, false, 0) {
draw(SkCanvas * canvas)5*c8dee2aaSAndroid Build Coastguard Worker void draw(SkCanvas* canvas) {
6*c8dee2aaSAndroid Build Coastguard Worker     SkPoint pts[] = {{ 10, 50 }, { 110, 80 }, { 10, 110 }};
7*c8dee2aaSAndroid Build Coastguard Worker     SkVector v[] = { pts[0] - pts[1], pts[2] - pts[1] };
8*c8dee2aaSAndroid Build Coastguard Worker     SkScalar angle1 = SkScalarATan2(v[0].fY, v[0].fX);
9*c8dee2aaSAndroid Build Coastguard Worker     SkScalar angle2 = SkScalarATan2(v[1].fY, v[1].fX);
10*c8dee2aaSAndroid Build Coastguard Worker     const SkScalar strokeWidth = 20;
11*c8dee2aaSAndroid Build Coastguard Worker     SkScalar miterLimit = 1 / SkScalarSin((angle2 - angle1) / 2);
12*c8dee2aaSAndroid Build Coastguard Worker     SkScalar miterLength = strokeWidth * miterLimit;
13*c8dee2aaSAndroid Build Coastguard Worker     SkPath path;
14*c8dee2aaSAndroid Build Coastguard Worker     path.moveTo(pts[0]);
15*c8dee2aaSAndroid Build Coastguard Worker     path.lineTo(pts[1]);
16*c8dee2aaSAndroid Build Coastguard Worker     path.lineTo(pts[2]);
17*c8dee2aaSAndroid Build Coastguard Worker     SkPaint paint;  // set to default kMiter_Join
18*c8dee2aaSAndroid Build Coastguard Worker     paint.setAntiAlias(true);
19*c8dee2aaSAndroid Build Coastguard Worker     paint.setStyle(SkPaint::kStroke_Style);
20*c8dee2aaSAndroid Build Coastguard Worker     paint.setStrokeMiter(miterLimit);
21*c8dee2aaSAndroid Build Coastguard Worker     paint.setStrokeWidth(strokeWidth);
22*c8dee2aaSAndroid Build Coastguard Worker     canvas->drawPath(path, paint);
23*c8dee2aaSAndroid Build Coastguard Worker     paint.setStrokeWidth(1);
24*c8dee2aaSAndroid Build Coastguard Worker     canvas->drawLine(pts[1].fX - miterLength / 2, pts[1].fY + 50,
25*c8dee2aaSAndroid Build Coastguard Worker                      pts[1].fX + miterLength / 2, pts[1].fY + 50, paint);
26*c8dee2aaSAndroid Build Coastguard Worker     canvas->translate(200, 0);
27*c8dee2aaSAndroid Build Coastguard Worker     miterLimit *= 0.99f;
28*c8dee2aaSAndroid Build Coastguard Worker     paint.setStrokeMiter(miterLimit);
29*c8dee2aaSAndroid Build Coastguard Worker     paint.setStrokeWidth(strokeWidth);
30*c8dee2aaSAndroid Build Coastguard Worker     canvas->drawPath(path, paint);
31*c8dee2aaSAndroid Build Coastguard Worker     paint.setStrokeWidth(1);
32*c8dee2aaSAndroid Build Coastguard Worker     canvas->drawLine(pts[1].fX - miterLength / 2, pts[1].fY + 50,
33*c8dee2aaSAndroid Build Coastguard Worker                      pts[1].fX + miterLength / 2, pts[1].fY + 50, paint);
34*c8dee2aaSAndroid Build Coastguard Worker }
35*c8dee2aaSAndroid Build Coastguard Worker }  // END FIDDLE
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