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javascript - 如何使用 PNGJS 库从 rgb 矩阵创建 png?

转载 作者:搜寻专家 更新时间:2023-11-01 00:17:49 25 4
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我无法根据此处的文档创建 PNG 文件(编码)https://github.com/niegowski/node-pngjs .该文档提供了一个操作现有 PNG 的示例。
为了完整性检查,我一直在尝试为每个像素赋予相同的 RGB 值。我认为这个问题帖子也很相关https://github.com/niegowski/node-pngjs/issues/20 .这是我试过的代码

var pic = new PNG({
width: cols,
height: rows
});
console.log(pic.width, pic.height);

var writeStream = fs.createWriteStream('C:\\Users\\yako\\desktop\\out.png');
pic.pack().pipe(writeStream);
writeStream.on('parsed', function() {
console.log('parsed');
});
writeStream.on('finish', function() {
fs.createReadStream('C:\\Users\\yako\\desktop\\out.png')
.pipe(new PNG({
filterType: -1
}))
.on('parsed', function() {

for (var y = 0; y < this.height; y++) {
for (var x = 0; x < this.width; x++) {
var idx = (this.width * y + x) << 2;


this.data[idx] = 255;
this.data[idx+1] = 218;
this.data[idx+2] = 185;


this.data[idx+3] = 0.5;
}
}

this.pack().pipe(fs.createWriteStream('C:\\Users\\yako\\desktop\\newOut.png'));
});
});
writeStream.on('error', function (err) {
console.error(err);
});

最佳答案

简单:

var fs = require('fs'),
PNG = require('pngjs').PNG;

var png = new PNG({
width: 100,
height: 100,
filterType: -1
});

for (var y = 0; y < png.height; y++) {
for (var x = 0; x < png.width; x++) {
var idx = (png.width * y + x) << 2;
png.data[idx ] = 255; // red
png.data[idx+1] = 218; // green
png.data[idx+2] = 185; // blue
png.data[idx+3] = 128; // alpha (0 is transparent)
}
}

png.pack().pipe(fs.createWriteStream('newOut.png'));

关于javascript - 如何使用 PNGJS 库从 rgb 矩阵创建 png?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/32259142/

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