svg-to-image

convert SVG text to a Image that can be drawn in canvas

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svg-to-image
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svg-to-image
experimental
Converts a string of SVG into an HTMLImageElement using Blob and URL.createObjectURL. Falls back to encodeURIComponent for unsupported browsers, such as Safari 8.0.

Install

npm install svg-to-image --save

Example

A common use case for this is rendering SVG to a 2D or WebGL canvas.
var svgToImage = require('svg-to-image')
var getContext = require('get-canvas-context')

// set up a new Canvas2D
var context = getContext('2d', {
  width: 200, height: 200
})

var data = [
  '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" width="200px" height="200px">',
    '<circle stroke-width="12" r="43" cx="50" cy="50" fill="none" stroke="#3A5"/>',
    '<circle r="6" cx="59" cy="23" fill="#000"/>',
    '<g stroke-linejoin="round" stroke-linecap="round" stroke-width="1" stroke="#000" fill="none">',
      '<path d="M36,36c5,0,3,2,8-1c1,2,1,3,3,2c3,0-6,7-3,8c-4-2-9,2-14-2c4-3,4-4,5-7c5,0,8,2,12,1"/>',
      '<path fill="#000" d="M34,29h31c2,5,7,10,7,16l-8,1l8,1l-3,31l-5,-18l-11,18l5-34l-3-8z"/>',
      '<path stroke-width="2" d="M27,48h23M28,49h21l-3,28h-14l-4,-28h5l3,28h3v-28h5l-2,28m3-4h-13m-1-5h16m0-5h-16m-1-5h18m0-5h-19"/>',
    '</g>',
    '<path stroke="#F00" stroke-width="1"/>',
  '</svg>'
].join('\n')

svgToImage(data, function (err, image) {
  if (err) throw err

  // draw image to canvas
  context.drawImage(image, 0, 0)

  // append to DOM
  var canvas = context.canvas
  document.body.appendChild(context.canvas)

  // open a PNG image the user can Right Click -> Save As
  window.open(context.canvas.toDataURL('image/png'))
})

Result:
svgImage
In Chrome and FireFox, you can also use this method for rendering DOM to canvas, by using <foreignObject> and well-formatted HTML.
var data = [
  '<svg xmlns="http://www.w3.org/2000/svg" width="200" height="200">',
    '<foreignObject width="100%" height="100%">',
      '<div xmlns="http://www.w3.org/1999/xhtml" style="font-size:40px">',
      '<em>I</em> like ', 
      '<span style="color:white; text-shadow:0 0 2px blue;">',
      'cheese</span>',
      '</div>',
    '</foreignObject>',
  '</svg>'
].join('\n')

Gotchas

  • The <svg> element should have both width and height fields, otherwise it may lead to undefined results
  • Rendering DOM needs to be wrapped in <foreignObject>, be well-formatted, and the root element should use the correct XML namespace
  • Only latest Chrome and FireFox have been tested with <foreignObject>

Usage

NPM

svgToImage(svg, [opt], [cb])

Converts the given svg string data into an HTMLImageElement, which can then be used to render to canvas.
You can optionally specify an opt.crossOrigin string, or omit the opt object.
The callback is called with (err, image) parameters, where err will be non-null in the case of a failure, and image is the rendered image.

License

MIT, see LICENSE.md for details.