34 lines
1.6 KiB
C++
34 lines
1.6 KiB
C++
// Copyright 2020 Google LLC.
|
|
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
|
|
#include "tools/fiddle/examples.h"
|
|
REG_FIDDLE(mapradius, 256, 256, false, 0) {
|
|
void draw(SkCanvas* canvas) {
|
|
SkPaint paint;
|
|
paint.setAntiAlias(true);
|
|
paint.setStyle(SkPaint::kStroke_Style);
|
|
SkMatrix matrix;
|
|
const SkPoint center = {128, 103};
|
|
matrix.setScale(2, .5f, center.fX, center.fY);
|
|
matrix.postRotate(45, center.fX, center.fY);
|
|
const SkScalar circleRadius = 60;
|
|
SkScalar mappedRadius = matrix.mapRadius(circleRadius);
|
|
SkVector minorAxis, majorAxis;
|
|
matrix.mapVector(0, circleRadius, &minorAxis);
|
|
matrix.mapVector(circleRadius, 0, &majorAxis);
|
|
paint.setColor(SK_ColorRED);
|
|
canvas->drawLine(40, 240, 40 + minorAxis.length(), 240, paint);
|
|
canvas->drawLine(42 + minorAxis.length(), 240, 42 + minorAxis.length() + majorAxis.length(),
|
|
240, paint);
|
|
paint.setColor(SK_ColorBLACK);
|
|
canvas->drawLine(center.fX, center.fY, center.fX + mappedRadius, center.fY, paint);
|
|
canvas->drawLine(center.fX, center.fY, center.fX, center.fY + mappedRadius, paint);
|
|
canvas->drawLine(40, 220, 40 + mappedRadius, 220, paint);
|
|
canvas->drawLine(42 + mappedRadius, 220, 42 + mappedRadius * 2, 220, paint);
|
|
canvas->concat(matrix);
|
|
canvas->drawCircle(center.fX, center.fY, circleRadius, paint);
|
|
paint.setColor(SK_ColorRED);
|
|
canvas->drawLine(center.fX, center.fY, center.fX + circleRadius, center.fY, paint);
|
|
canvas->drawLine(center.fX, center.fY, center.fX, center.fY + circleRadius, paint);
|
|
}
|
|
} // END FIDDLE
|