xref: /aosp_15_r20/external/skia/docs/examples/Canvas_readPixels_a.cpp (revision c8dee2aa9b3f27cf6c858bd81872bdeb2c07ed17)
1 // Copyright 2019 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"
4 REG_FIDDLE(Canvas_readPixels_a, 64, 64, false, 0) {
draw(SkCanvas * canvas)5 void draw(SkCanvas* canvas) {
6     canvas->clear(SK_ColorBLUE);
7     SkPaint paint;
8     canvas->drawCircle(32, 32, 28, paint);
9     SkImageInfo info = SkImageInfo::Make(64, 64, kBGRA_8888_SkColorType, kPremul_SkAlphaType);
10     sk_sp<SkData> data(SkData::MakeUninitialized(info.minRowBytes() * info.height()));
11     sk_bzero(data->writable_data(), info.minRowBytes() * info.height());
12     for (int x : { 32, -32 } ) {
13         for (int y : { 32, -32 } ) {
14             canvas->readPixels(info, data->writable_data(), info.minRowBytes(), x, y);
15         }
16     }
17     sk_sp<SkImage> image = SkImages::RasterFromData(info, data, info.minRowBytes());
18     canvas->drawImage(image, 0, 0);
19 }
20 }  // END FIDDLE
21