skia2/docs/examples/Alpha_Constants_a.cpp
Mike Reed 34a0c97f5e don't use drawBitmap
Bug: skia:11216
Change-Id: I89a40e330f27f30c461f2b6012bf26c082b66094
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/359076
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2021-01-26 02:24:21 +00:00

37 lines
1.7 KiB
C++

// Copyright 2019 Google LLC.
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
#include "tools/fiddle/examples.h"
// HASH=bc9c7ea424d10bbcd1e5a88770d4794e
REG_FIDDLE(Alpha_Constants_a, 256, 128, false, 1) {
void draw(SkCanvas* canvas) {
std::vector<int32_t> srcPixels;
srcPixels.resize(source.height() * source.rowBytes());
SkPixmap pixmap(SkImageInfo::MakeN32Premul(source.width(), source.height()),
&srcPixels.front(), source.rowBytes());
source.readPixels(pixmap, 0, 0);
for (int y = 0; y < 16; ++y) {
for (int x = 0; x < 16; ++x) {
int32_t* blockStart = &srcPixels.front() + y * source.width() * 16 + x * 16;
size_t transparentCount = 0;
for (int fillY = 0; fillY < source.height() / 16; ++fillY) {
for (int fillX = 0; fillX < source.width() / 16; ++fillX) {
const SkColor color = SkUnPreMultiply::PMColorToColor(blockStart[fillX]);
transparentCount += SkColorGetA(color) == SK_AlphaTRANSPARENT;
}
blockStart += source.width();
}
if (transparentCount > 200) {
blockStart = &srcPixels.front() + y * source.width() * 16 + x * 16;
for (int fillY = 0; fillY < source.height() / 16; ++fillY) {
for (int fillX = 0; fillX < source.width() / 16; ++fillX) {
blockStart[fillX] = SK_ColorRED;
}
blockStart += source.width();
}
}
}
}
canvas->drawImage(SkImage::MakeRasterCopy(pixmap), 0, 0);
}
} // END FIDDLE