1// Copyright 2020 Google LLC.
2// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
3#include "tools/fiddle/examples.h"
4REG_FIDDLE(mapradius, 256, 256, false, 0) {
5void draw(SkCanvas* canvas) {
6    SkPaint paint;
7    paint.setAntiAlias(true);
8    paint.setStyle(SkPaint::kStroke_Style);
9    SkMatrix matrix;
10    const SkPoint center = {128, 103};
11    matrix.setScale(2, .5f, center.fX, center.fY);
12    matrix.postRotate(45, center.fX, center.fY);
13    const SkScalar circleRadius = 60;
14    SkScalar mappedRadius = matrix.mapRadius(circleRadius);
15    SkVector minorAxis, majorAxis;
16    matrix.mapVector(0, circleRadius, &minorAxis);
17    matrix.mapVector(circleRadius, 0, &majorAxis);
18    paint.setColor(SK_ColorRED);
19    canvas->drawLine(40, 240, 40 + minorAxis.length(), 240, paint);
20    canvas->drawLine(42 + minorAxis.length(), 240, 42 + minorAxis.length() + majorAxis.length(),
21                     240, paint);
22    paint.setColor(SK_ColorBLACK);
23    canvas->drawLine(center.fX, center.fY, center.fX + mappedRadius, center.fY, paint);
24    canvas->drawLine(center.fX, center.fY, center.fX, center.fY + mappedRadius, paint);
25    canvas->drawLine(40, 220, 40 + mappedRadius, 220, paint);
26    canvas->drawLine(42 + mappedRadius, 220, 42 + mappedRadius * 2, 220, paint);
27    canvas->concat(matrix);
28    canvas->drawCircle(center.fX, center.fY, circleRadius, paint);
29    paint.setColor(SK_ColorRED);
30    canvas->drawLine(center.fX, center.fY, center.fX + circleRadius, center.fY, paint);
31    canvas->drawLine(center.fX, center.fY, center.fX, center.fY + circleRadius, paint);
32}
33}  // END FIDDLE
34