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