xref: /aosp_15_r20/external/skia/docs/examples/Surface_readPixels_2.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(Surface_readPixels_2, 256, 64, false, 0) {
draw(SkCanvas * canvas)5  void draw(SkCanvas* canvas) {
6      sk_sp<SkSurface> surf(SkSurfaces::Raster(SkImageInfo::MakeN32Premul(64, 64)));
7      auto surfCanvas = surf->getCanvas();
8      surfCanvas->clear(SK_ColorRED);
9      SkPaint paint;
10      surfCanvas->drawOval({4, 8, 58, 54}, paint);
11      SkImageInfo info = SkImageInfo::Make(64, 64, kBGRA_8888_SkColorType, kPremul_SkAlphaType);
12      sk_sp<SkData> data(SkData::MakeUninitialized(info.minRowBytes() * info.height()));
13      sk_bzero(data->writable_data(), info.minRowBytes() * info.height());
14      for (int x : { 32, -32 } ) {
15          for (int y : { 32, -32 } ) {
16              surf->readPixels(info, data->writable_data(), info.minRowBytes(), x, y);
17          }
18      }
19      sk_sp<SkImage> image = SkImages::RasterFromData(info, data, info.minRowBytes());
20      canvas->drawImage(image, 0, 0);
21  }
22  }  // END FIDDLE
23