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
5REG_FIDDLE(Alpha_Constants_a, 256, 128, false, 1) {
6void 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