xref: /aosp_15_r20/external/skia/docs/examples/Pixmap_writable_addr32.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(Pixmap_writable_addr32, 256, 72, false, 4) {
draw(SkCanvas * canvas)5 void draw(SkCanvas* canvas) {
6     std::vector<int32_t> pixels;
7     pixels.resize(image->height() * image->width() * 4);
8     SkPixmap pixmap(SkImageInfo::Make(image->width(), image->height(), kN32_SkColorType,
9             image->alphaType()), (const void*) &pixels.front(), image->width() * 4);
10     image->readPixels(nullptr, pixmap, 0, 0);
11     for (int y = 0; y < pixmap.height() / 2; ++y) {
12         for (int x = 0; x < pixmap.width(); ++x) {
13             if ((x & 4) == (y & 4)) {
14                 *pixmap.writable_addr32(x, y) =
15                         *pixmap.writable_addr32(pixmap.width() - x - 1, pixmap.height() - y - 1);
16             }
17         }
18     }
19     SkBitmap bitmap;
20     bitmap.installPixels(pixmap);
21     canvas->drawImage(bitmap.asImage(), 0, 0);
22 }
23 }  // END FIDDLE
24