skia2/docs/examples/Canvas_001.cpp

31 lines
1.3 KiB
C++
Raw Normal View History

// 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=87f55e62ec4c3535e1a5d0f1415b20c6
REG_FIDDLE(Canvas_001, 256, 256, true, 0) {
void draw(SkCanvas* ) {
const int width = 3;
const int height = 3;
SkPMColor pixels[height][width]; // allocate a 3 by 3 Premultiplied bitmap on the stack
// create a SkCanvas backed by a raster device, and delete it when the
// function goes out of scope.
std::unique_ptr<SkCanvas> canvas = SkCanvas::MakeRasterDirectN32(
width,
height,
pixels[0], // top-left of the bitmap
sizeof(pixels[0])); // byte width of the each row
// write a Premultiplied value for white into all pixels in the bitmap
canvas->clear(SK_ColorWHITE);
SkPMColor pmWhite = pixels[0][0]; // the Premultiplied format may vary
SkPaint paint; // by default, draws black
canvas->drawPoint(1, 1, paint); // draw in the center
canvas->flush(); // ensure that pixels is ready to be read
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width; ++x) {
SkDebugf("%c", pixels[y][x] == pmWhite ? '-' : 'x');
}
SkDebugf("\n");
}
}
} // END FIDDLE