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 // HASH=bc9c7ea424d10bbcd1e5a88770d4794e
5 REG_FIDDLE(Alpha_Constants_a, 256, 128, false, 1) {
draw(SkCanvas * canvas)6 void draw(SkCanvas* canvas) {
7     std::vector<int32_t> srcPixels;
8     srcPixels.resize(source.height() * source.rowBytes());
9     SkPixmap pixmap(SkImageInfo::MakeN32Premul(source.width(), source.height()),
10                     &srcPixels.front(), source.rowBytes());
11     source.readPixels(pixmap, 0, 0);
12     for (int y = 0; y < 16; ++y) {
13         for (int x = 0; x < 16; ++x) {
14             int32_t* blockStart = &srcPixels.front() + y * source.width() * 16 + x * 16;
15             size_t transparentCount = 0;
16             for (int fillY = 0; fillY < source.height() / 16; ++fillY) {
17                 for (int fillX = 0; fillX < source.width() / 16; ++fillX) {
18                     const SkColor color = SkUnPreMultiply::PMColorToColor(blockStart[fillX]);
19                     transparentCount += SkColorGetA(color) == SK_AlphaTRANSPARENT;
20                 }
21                 blockStart += source.width();
22             }
23             if (transparentCount > 200) {
24                 blockStart = &srcPixels.front() + y * source.width() * 16 + x * 16;
25                 for (int fillY = 0; fillY < source.height() / 16; ++fillY) {
26                     for (int fillX = 0; fillX < source.width() / 16; ++fillX) {
27                         blockStart[fillX] = SK_ColorRED;
28                     }
29                     blockStart += source.width();
30                 }
31             }
32         }
33     }
34     canvas->drawImage(SkImage::MakeRasterCopy(pixmap), 0, 0);
35 }
36 }  // END FIDDLE
37