pdfmake/src/svgMeasure.js

Client/server side PDF printing in pure JavaScript

'use strict';

var xmldoc = require('xmldoc');
var isString = require('./helpers').isString;

/** Strip unit postfix, parse number, but return undefined instead of NaN for bad input */
function stripUnits(textVal) {
	var n = parseFloat(textVal);
	if (typeof n !== 'number' || isNaN(n)) {
		return undefined;
	}
	return n;
}

/** Make sure it's valid XML and the root tage is <svg/>, returns xmldoc DOM */
function parseSVG(svgString) {
	var doc;

	try {
		doc = new xmldoc.XmlDocument(svgString);
	} catch (err) {
		throw new Error('Invalid svg document (' + err + ')');
	}

	if (doc.name !== "svg") {
		throw new Error('Invalid svg document (expected <svg>)');
	}

	return doc;
}

function SVGMeasure() {
}

SVGMeasure.prototype.measureSVG = function (svg) {
	var width, height, viewBox;

	if (isString(svg)) {
		var doc = parseSVG(svg);

		width = doc.attr.width;
		height = doc.attr.height;
		viewBox = doc.attr.viewBox;
	} else if (typeof SVGElement !== 'undefined' && svg instanceof SVGElement && typeof getComputedStyle === 'function') {
		width = svg.getAttribute("width");
		height = svg.getAttribute("height");
		viewBox = svg.getAttribute("viewBox");
	} else {
		throw new Error('Invalid SVG document');
	}

	var docWidth = stripUnits(width);
	var docHeight = stripUnits(height);

	if ((docWidth == undefined || docHeight == undefined) && typeof viewBox == 'string') {
		var viewBoxParts = viewBox.split(/[,\s]+/);
		if (viewBoxParts.length !== 4) {
			throw new Error("Unexpected svg viewBox format, should have 4 entries but found: '" + viewBox + "'");
		}
		if (docWidth == undefined) {
			docWidth = stripUnits(viewBoxParts[2]);
		}
		if (docHeight == undefined) {
			docHeight = stripUnits(viewBoxParts[3]);
		}
	}

	return {
		width: docWidth,
		height: docHeight
	};
};

SVGMeasure.prototype.writeDimensions = function (svg, dimensions) {
	if (isString(svg)) {
		var doc = parseSVG(svg);

		if (typeof doc.attr.viewBox !== 'string') {
			doc.attr.viewBox = `0 0 ${stripUnits(doc.attr.width)} ${stripUnits(doc.attr.height)}`;
		}

		doc.attr.width = "" + dimensions.width;
		doc.attr.height = "" + dimensions.height;

		return doc.toString();
	}

	if (!svg.hasAttribute('viewBox')) {
		svg.setAttribute('viewBox', `0 0 ${stripUnits(svg.getAttribute('width'))} ${stripUnits(svg.getAttribute('height'))}`);
	}

	svg.setAttribute('width', "" + dimensions.width);
	svg.setAttribute('height', "" + dimensions.height);

	return svg;
};

module.exports = SVGMeasure;