Save SVGs as PNGs from the browser.
HTML JavaScript
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exupero Change how background color is implemented.
Instead of filling a rectangle on the canvas, set the SVG's background
color with CSS. Simpler, and also makes it possible to unset a
CSS background color so the image has a transparent background while the
SVG doesn't.
Latest commit 9916814 Aug 12, 2018

README.md

saveSvgAsPng

Installation

npm install save-svg-as-png

Prerequisites

SaveSvgAsPng relies on JavaScript promises, so any browsers that don't natively support the standard Promise object will need to have a polyfill.

Usage

To save a PNG, include the script saveSvgAsPng.js in your page, then call the saveSvgAsPng function with an SVG node and a filename:

saveSvgAsPng(document.getElementById("diagram"), "diagram.png");

The filename is the preferred filename when saving the image to the file system. The browser may change the name of the file if there is already a file by that name in the target directory.

If you want to scale the image up or down, you can pass a scale factor in an options object:

saveSvgAsPng(document.getElementById("diagram"), "diagram.png", {scale: 0.5});

Other options are documented below.

If you just want a dataURI for an SVG, you can call svgAsDataUri with an SVG node, options, and a callback:

svgAsDataUri(document.getElementById("diagram"), {}, function(uri) {
  ...
});

If you want a dataURI of a PNG generated from an SVG, you can call svgAsPngUri with an SVG node, options, and a callback:

svgAsPngUri(document.getElementById("diagram"), {}, function(uri) {
  ...
});

Compatible with browserify and requirejs.

If you want to use TypeScript, necessary type definitions are available in Typings public registry.

Options

  • backgroundColor — Creates a PNG with the given background color. Defaults to transparent.
  • canvg - If canvg is passed in, it will be used to write svg to canvas. This will allow support for Internet Explorer
  • encoderOptions - A Number between 0 and 1 indicating image quality. The default is 0.8
  • encoderType - A DOMString indicating the image format. The default type is image/png.
  • fonts - A list of {text, url, format} objects the specify what fonts to inline in the SVG. Omitting this option defaults to auto-detecting font rules.
  • height - Specify the image's height. Defaults to the viewbox's height if given, or the element's non-percentage height, or the element's bounding box's height, or the element's CSS height, or the computed style's height, or 0.
  • left - Specify the viewbox's left position. Defaults to 0.
  • modifyCss - A function that takes a CSS rule's selector and properties and returns a string of CSS. Supercedes selectorRemap and modifyStyle. Useful for modifying properties only for certain CSS selectors.
  • modifyStyle - A function that takes a CSS rule's properties and returns a string of CSS. Useful for modifying properties before they're inlined into the SVG.
  • scale — Changes the resolution of the output PNG. Defaults to 1, the same dimensions as the source SVG.
  • selectorRemap — A function that takes a CSS selector and produces its replacement in the CSS that's inlined into the SVG. Useful if your SVG style selectors are scoped by ancestor elements in your HTML document.
  • top - Specify the viewbox's top position. Defaults to 0.
  • width - Specify the image's width. Defaults to the viewbox's width if given, or the element's non-percentage width, or the element's bounding box's width, or the element's CSS width, or the computed style's width, or 0.

Testing

run tests with tape

npm test

Support

Chrome limits data URIs to 2MB, so you may have trouble generating PNGs beyod a certain size.

Internet Explorer will only work if canvg is passed in, otherwise it will throw a SecurityError when calling toDataURL on a canvas that's been written to. canvg may have it's own issues with SVG support, so ensure you test the output after switching.