saveSvgAsPng.js

(function() {
  var out$ = typeof exports != 'undefined' && exports || this;

  var doctype = '<?xml version="1.0" standalone="no"?><!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">';

  function isExternal(url) {
    return url && url.lastIndexOf('http',0) == 0 && url.lastIndexOf(window.location.host) == -1;
  }

  function inlineImages(el, callback) {
    var images = el.querySelectorAll('image');
    var left = images.length;
    if (left == 0) {
      callback();
    }
    for (var i = 0; i < images.length; i++) {
      (function(image) {
        var href = image.getAttributeNS("http://www.w3.org/1999/xlink", "href");
        if (href) {
          if (isExternal(href.value)) {
            console.warn("Cannot render embedded images linking to external hosts: "+href.value);
            return;
          }
        }
        var canvas = document.createElement('canvas');
        var ctx = canvas.getContext('2d');
        var img = new Image();
        href = href || image.getAttribute('href');
        img.src = href;
        img.onload = function() {
          canvas.width = img.width;
          canvas.height = img.height;
          ctx.drawImage(img, 0, 0);
          image.setAttributeNS("http://www.w3.org/1999/xlink", "href", canvas.toDataURL('image/png'));
          left--;
          if (left == 0) {
            callback();
          }
        }
        img.onerror = function() {
          console.log("Could not load "+href);
          left--;
          if (left == 0) {
            callback();
          }
        }
      })(images[i]);
    }
  }

  function styles(el, selectorRemap) {
    var css = "";
    var sheets = document.styleSheets;
    for (var i = 0; i < sheets.length; i++) {
      try {
        var rules = sheets[i].cssRules;
      } catch (e) {
        console.warn("Stylesheet could not be loaded: "+sheets[i].href);
        continue;
      }

      if (rules != null) {
        for (var j = 0; j < rules.length; j++) {
          var rule = rules[j];
          if (typeof(rule.style) != "undefined") {
            var match = null;
            try {
              match = el.querySelector(rule.selectorText);
            } catch(err) {
              console.warn('Invalid CSS selector "' + rule.selectorText + '"', err);
            }
            if (match) {
              var selector = selectorRemap ? selectorRemap(rule.selectorText) : rule.selectorText;
              css += selector + " { " + rule.style.cssText + " }\n";
            } else if(rule.cssText.match(/^@font-face/)) {
              css += rule.cssText + '\n';
            }
          }
        }
      }
    }
    return css;
  }

  function getDimension(el, clone, dim) {
    var v = (el.viewBox.baseVal && el.viewBox.baseVal[dim]) ||
      (clone.getAttribute(dim) !== null && !clone.getAttribute(dim).match(/%$/) && parseInt(clone.getAttribute(dim))) ||
      el.getBoundingClientRect()[dim] ||
      parseInt(clone.style[dim]) ||
      parseInt(window.getComputedStyle(el).getPropertyValue(dim));
    return (typeof v === 'undefined' || v === null || isNaN(parseFloat(v))) ? 0 : v;
  }

  function reEncode(data) {
    data = encodeURIComponent(data);
    data = data.replace(/%([0-9A-F]{2})/g, function(match, p1) {
      var c = String.fromCharCode('0x'+p1);
      return c === '%' ? '%25' : c;
    });
    return decodeURIComponent(data);
  }

  out$.svgAsDataUri = function(el, options, cb) {
    options = options || {};
    options.scale = options.scale || 1;
    var xmlns = "http://www.w3.org/2000/xmlns/";

    inlineImages(el, function() {
      var outer = document.createElement("div");
      var clone = el.cloneNode(true);
      var width, height;
      if(el.tagName == 'svg') {
        width = options.width || getDimension(el, clone, 'width');
        height = options.height || getDimension(el, clone, 'height');
      } else if(el.getBBox) {
        var box = el.getBBox();
        width = box.x + box.width;
        height = box.y + box.height;
        clone.setAttribute('transform', clone.getAttribute('transform').replace(/translate\(.*?\)/, ''));

        var svg = document.createElementNS('http://www.w3.org/2000/svg','svg')
        svg.appendChild(clone)
        clone = svg;
      } else {
        console.error('Attempted to render non-SVG element', el);
        return;
      }

      clone.setAttribute("version", "1.1");
      clone.setAttributeNS(xmlns, "xmlns", "http://www.w3.org/2000/svg");
      clone.setAttributeNS(xmlns, "xmlns:xlink", "http://www.w3.org/1999/xlink");
      clone.setAttribute("width", width * options.scale);
      clone.setAttribute("height", height * options.scale);
      clone.setAttribute("viewBox", [
        options.left || 0,
        options.top || 0,
        width,
        height
      ].join(" "));

      outer.appendChild(clone);

      var css = styles(el, options.selectorRemap);
      var s = document.createElement('style');
      s.setAttribute('type', 'text/css');
      s.innerHTML = "<![CDATA[\n" + css + "\n]]>";
      var defs = document.createElement('defs');
      defs.appendChild(s);
      clone.insertBefore(defs, clone.firstChild);

      var svg = doctype + outer.innerHTML;
      var uri = 'data:image/svg+xml;base64,' + window.btoa(reEncode(svg));
      if (cb) {
        cb(uri);
      }
    });
  }

  out$.svgAsPngUri = function(el, options, cb) {
    out$.svgAsDataUri(el, options, function(uri) {
      var image = new Image();
      image.onload = function() {
        var canvas = document.createElement('canvas');
        canvas.width = image.width;
        canvas.height = image.height;
        var context = canvas.getContext('2d');
        if(options && options.backgroundColor){
          context.fillStyle = options.backgroundColor;
          context.fillRect(0, 0, canvas.width, canvas.height);
        }
        context.drawImage(image, 0, 0);
        var a = document.createElement('a');
        cb(canvas.toDataURL('image/png'));
      }
      image.src = uri;
    });
  }

  out$.saveSvgAsPng = function(el, name, options) {
    options = options || {};
    out$.svgAsPngUri(el, options, function(uri) {
      var a = document.createElement('a');
      a.download = name;
      a.href = uri;
      document.body.appendChild(a);
      a.addEventListener("click", function(e) {
        a.parentNode.removeChild(a);
      });
      a.click();
    });
  }
})();