node_modules.image-size.lib.types.png.js Maven / Gradle / Ivy
'use strict';
var pngSignature = 'PNG\r\n\x1a\n';
function isPNG (buffer) {
if (pngSignature === buffer.toString('ascii', 1, 8)) {
if ('IHDR' !== buffer.toString('ascii', 12, 16)) {
throw new TypeError('invalid png');
}
return true;
}
}
function calculate (buffer) {
return {
'width': buffer.readUInt32BE(16),
'height': buffer.readUInt32BE(20)
};
}
module.exports = {
'detect': isPNG,
'calculate': calculate
};