30 lines
1.2 KiB
C++
30 lines
1.2 KiB
C++
// Copyright 2019 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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// HASH=092739b4cd5d732a27c07ced8ef45f01
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REG_FIDDLE(Bitmap_extractAlpha_2, 256, 160, false, 0) {
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void draw(SkCanvas* canvas) {
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auto radiusToSigma = [](SkScalar radius) -> SkScalar {
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static const SkScalar kBLUR_SIGMA_SCALE = 0.57735f;
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return radius > 0 ? kBLUR_SIGMA_SCALE * radius + 0.5f : 0.0f;
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};
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SkBitmap alpha, bitmap;
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bitmap.allocN32Pixels(100, 100);
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SkCanvas offscreen(bitmap);
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offscreen.clear(0);
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SkPaint paint;
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paint.setAntiAlias(true);
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paint.setColor(SK_ColorBLUE);
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paint.setStyle(SkPaint::kStroke_Style);
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paint.setStrokeWidth(20);
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offscreen.drawCircle(50, 50, 39, paint);
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offscreen.flush();
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paint.setMaskFilter(SkMaskFilter::MakeBlur(kNormal_SkBlurStyle, radiusToSigma(25)));
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SkIPoint offset;
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bitmap.extractAlpha(&alpha, &paint, &offset);
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paint.setColor(SK_ColorRED);
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canvas->drawImage(bitmap.asImage(), 0, -offset.fY, SkSamplingOptions(), &paint);
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canvas->drawImage(alpha.asImage(), 100 + offset.fX, 0, SkSamplingOptions(), &paint);
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}
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} // END FIDDLE
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