png-js
v1.0.0
Published
A PNG decoder in JavaScript
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png.js
A PNG decoder in JS for the canvas element or Node.js.
Browser Usage
Simply include png.js and zlib.js on your HTML page, create a canvas element, and call PNG.load to load an image.
<canvas></canvas>
<script src="zlib.js"></script>
<script src="png.js"></script>
<script>
var canvas = document.getElementsByTagName('canvas')[0];
PNG.load('some.png', canvas);
</script>
The source code for the browser version resides in png.js
and also supports loading and displaying animated PNGs.
Node.js Usage
Install the module using npm
sudo npm install png-js
Require the module and decode a PNG
var PNG = require('png-js');
PNG.decode('some.png', function(pixels) {
// pixels is a 1d array (in rgba order) of decoded pixel data
});
You can also call PNG.load
if you want to load the PNG (but not decode the pixels) synchronously. If you already
have the PNG data in a buffer, simply use new PNG(buffer)
. In both of these cases, you need to call png.decode
yourself which passes your callback the decoded pixels as a buffer. If you already have a buffer you want the pixels
copied to, call copyToImageData
with your buffer and the decoded pixels as returned from decodePixels
.