forked from image-size/image-size
/
svg.js
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svg.js
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'use strict';
var svgReg = /<svg\s([^>"']|"[^"]*"|'[^']*')*>/;
function isSVG (buffer) {
return svgReg.test(buffer);
}
var extractorRegExps = {
'root': svgReg,
'width': /\bwidth=(['"])([^%]+?)\1/,
'height': /\bheight=(['"])([^%]+?)\1/,
'viewbox': /\bviewBox=(['"])(.+?)\1/
};
function parseViewbox (viewbox) {
var bounds = viewbox.split(' ');
return {
'width': parseInt(bounds[2], 10),
'height': parseInt(bounds[3], 10)
};
}
function parseAttributes (root) {
var width = root.match(extractorRegExps.width);
var height = root.match(extractorRegExps.height);
var viewbox = root.match(extractorRegExps.viewbox);
return {
'width': width && parseInt(width[2], 10),
'height': height && parseInt(height[2], 10),
'viewbox': viewbox && parseViewbox(viewbox[2])
};
}
function calculateByDimensions (attrs) {
return {
'width': attrs.width,
'height': attrs.height
};
}
function calculateByViewbox (attrs) {
var ratio = attrs.viewbox.width / attrs.viewbox.height;
if (attrs.width) {
return {
'width': attrs.width,
'height': Math.floor(attrs.width / ratio)
};
}
if (attrs.height) {
return {
'width': Math.floor(attrs.height * ratio),
'height': attrs.height
};
}
return {
'width': attrs.viewbox.width,
'height': attrs.viewbox.height
};
}
function calculate (buffer) {
var root = buffer.toString('utf8').match(extractorRegExps.root);
if (root) {
var attrs = parseAttributes(root[0]);
if (attrs.width && attrs.height) {
return calculateByDimensions(attrs);
}
if (attrs.viewbox) {
return calculateByViewbox(attrs);
}
}
throw new TypeError('invalid svg');
}
module.exports = {
'detect': isSVG,
'calculate': calculate
};