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