xref: /aosp_15_r20/external/skia/docs/examples/Canvas_copy_const_SkBitmap.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_copy_const_SkBitmap, 256, 256, true, 0) {
draw(SkCanvas *)5 void draw(SkCanvas* ) {
6     SkBitmap bitmap;
7     // create a bitmap 5 wide and 11 high
8     bitmap.allocPixels(SkImageInfo::MakeN32Premul(5, 11));
9     SkCanvas canvas(bitmap);
10     canvas.clear(SK_ColorWHITE);  // white is Unpremultiplied, in ARGB order
11     SkPixmap pixmap;  // provides guaranteed access to the drawn pixels
12     if (!canvas.peekPixels(&pixmap)) {
13         SkDebugf("peekPixels should never fail.\n");
14     }
15     const SkPMColor* pixels = pixmap.addr32();  // points to top-left of bitmap
16     SkPMColor pmWhite = pixels[0];  // the Premultiplied format may vary
17     SkPaint paint;  // by default, draws black, 12 point text
18     SkFont font = SkFont(fontMgr->matchFamilyStyle(nullptr, {}));
19     canvas.drawString("!", 1, 10, font, paint);  // 1 char at baseline (1, 10)
20     for (int y = 0; y < bitmap.height(); ++y) {
21         for (int x = 0; x < bitmap.width(); ++x) {
22             SkDebugf("%c", *pixels++ == pmWhite ? '-' : 'x');
23         }
24         SkDebugf("\n");
25     }
26 }
27 }  // END FIDDLE
28