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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, which returns a promise:

svgAsDataUri(document.getElementById("diagram"), options).then(uri => ...);

If you want a dataURI of a PNG generated from an SVG, you can call svgAsPngUri, which also returns a promise:

svgAsPngUri(document.getElementById("diagram"), options).then(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.
  • excludeUnusedCss - Exclude CSS rules that don't match any elements in the SVG.
  • excludeCss - Exclude all CSS rules

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 make sure to test the output.