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(Bitmap_extractAlpha_2, 256, 160, false, 0) {
draw(SkCanvas * canvas)5*c8dee2aaSAndroid Build Coastguard Worker void draw(SkCanvas* canvas) {
6*c8dee2aaSAndroid Build Coastguard Worker auto radiusToSigma = [](SkScalar radius) -> SkScalar {
7*c8dee2aaSAndroid Build Coastguard Worker static const SkScalar kBLUR_SIGMA_SCALE = 0.57735f;
8*c8dee2aaSAndroid Build Coastguard Worker return radius > 0 ? kBLUR_SIGMA_SCALE * radius + 0.5f : 0.0f;
9*c8dee2aaSAndroid Build Coastguard Worker };
10*c8dee2aaSAndroid Build Coastguard Worker SkBitmap alpha, bitmap;
11*c8dee2aaSAndroid Build Coastguard Worker bitmap.allocN32Pixels(100, 100);
12*c8dee2aaSAndroid Build Coastguard Worker SkCanvas offscreen(bitmap);
13*c8dee2aaSAndroid Build Coastguard Worker offscreen.clear(0);
14*c8dee2aaSAndroid Build Coastguard Worker SkPaint paint;
15*c8dee2aaSAndroid Build Coastguard Worker paint.setAntiAlias(true);
16*c8dee2aaSAndroid Build Coastguard Worker paint.setColor(SK_ColorBLUE);
17*c8dee2aaSAndroid Build Coastguard Worker paint.setStyle(SkPaint::kStroke_Style);
18*c8dee2aaSAndroid Build Coastguard Worker paint.setStrokeWidth(20);
19*c8dee2aaSAndroid Build Coastguard Worker offscreen.drawCircle(50, 50, 39, paint);
20*c8dee2aaSAndroid Build Coastguard Worker paint.setMaskFilter(SkMaskFilter::MakeBlur(kNormal_SkBlurStyle, radiusToSigma(25)));
21*c8dee2aaSAndroid Build Coastguard Worker SkIPoint offset;
22*c8dee2aaSAndroid Build Coastguard Worker bitmap.extractAlpha(&alpha, &paint, &offset);
23*c8dee2aaSAndroid Build Coastguard Worker paint.setColor(SK_ColorRED);
24*c8dee2aaSAndroid Build Coastguard Worker canvas->drawImage(bitmap.asImage(), 0, -offset.fY, SkSamplingOptions(), &paint);
25*c8dee2aaSAndroid Build Coastguard Worker canvas->drawImage(alpha.asImage(), 100 + offset.fX, 0, SkSamplingOptions(), &paint);
26*c8dee2aaSAndroid Build Coastguard Worker }
27*c8dee2aaSAndroid Build Coastguard Worker } // END FIDDLE
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