xref: /aosp_15_r20/external/skia/docs/examples/Bitmap_writePixels.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_writePixels, 256, 256, false, 3) {
draw(SkCanvas * canvas)5 void draw(SkCanvas* canvas) {
6     std::vector<int32_t> srcPixels;
7     int width = image->width();
8     int height = image->height();
9     srcPixels.resize(height * width  * 4);
10     SkPixmap pixmap(SkImageInfo::MakeN32Premul(width, height), (const void*) &srcPixels.front(),
11                     width * 4);
12     image->readPixels(nullptr, pixmap, 0, 0);
13     canvas->scale(.5f, .5f);
14     width /= 4;
15     height /= 4;
16     for (int y = 0; y < 4; ++y) {
17         for (int x = 0; x < 4; ++x) {
18             SkBitmap bitmap;
19             bitmap.allocPixels(SkImageInfo::MakeN32Premul(width, height));
20             bitmap.writePixels(pixmap, -y * width, -x * height);
21             canvas->drawImage(bitmap.asImage(), x * width, y * height);
22         }
23     }
24 }
25 }  // END FIDDLE
26