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