skia2/docs/examples/Canvas_accessTopLayerPixels_b.cpp
Hal Canary d88c2e8e09 Docs: rename examples files to match names
Change-Id: I9a6b2780cfdd91cdd16d5a08eb9ba1214492cb7e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/201982
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Hal Canary <halcanary@google.com>
2019-03-19 18:49:22 +00:00

41 lines
1.3 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 "fiddle/examples.h"
// HASH=a7ac9c21bbabcdeeca00f72a61cd0f3e
REG_FIDDLE(Canvas_accessTopLayerPixels_b, 256, 256, false, 0) {
void draw(SkCanvas* canvas) {
SkPaint paint;
SkFont font(nullptr, 100);
canvas->drawString("ABC", 20, 160, font, paint);
SkRect layerBounds = SkRect::MakeXYWH(32, 32, 192, 192);
canvas->saveLayerAlpha(&layerBounds, 128);
canvas->clear(SK_ColorWHITE);
canvas->drawString("DEF", 20, 160, font, paint);
SkImageInfo imageInfo;
size_t rowBytes;
SkIPoint origin;
uint32_t* access = (uint32_t*) canvas->accessTopLayerPixels(&imageInfo, &rowBytes, &origin);
if (access) {
int h = imageInfo.height();
int v = imageInfo.width();
int rowWords = rowBytes / sizeof(uint32_t);
for (int y = 0; y < h; ++y) {
int newY = (y - h / 2) * 2 + h / 2;
if (newY < 0 || newY >= h) {
continue;
}
for (int x = 0; x < v; ++x) {
int newX = (x - v / 2) * 2 + v / 2;
if (newX < 0 || newX >= v) {
continue;
}
if (access[y * rowWords + x] == SK_ColorBLACK) {
access[newY * rowWords + newX] = SK_ColorGRAY;
}
}
}
}
canvas->restore();
}
} // END FIDDLE