xref: /aosp_15_r20/external/skia/docs/examples/Bitmap_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(Bitmap_readPixels_2, 256, 256, false, 3) {
draw(SkCanvas * canvas)5 void draw(SkCanvas* canvas) {
6     std::vector<int32_t> srcPixels;
7     srcPixels.resize(source.height() * source.rowBytes());
8     for (int y = 0; y < 4; ++y) {
9         for (int x = 0; x < 4; ++x) {
10             SkPixmap pixmap(SkImageInfo::MakeN32Premul(source.width() / 4, source.height() / 4),
11                     &srcPixels.front() + x * source.height() * source.width() / 4 +
12                     y * source.width() / 4, source.rowBytes());
13             source.readPixels(pixmap, x * source.width() / 4, y * source.height() / 4);
14         }
15     }
16     canvas->scale(.5f, .5f);
17     SkBitmap bitmap;
18     bitmap.installPixels(SkImageInfo::MakeN32Premul(source.width(), source.height()),
19                              &srcPixels.front(), source.rowBytes());
20     canvas->drawImage(bitmap.asImage(), 0, 0);
21 }
22 }  // END FIDDLE
23