/svg-exportJS

A Javascript library to export svg charts from the DOM and download them as an SVG file, PDF, or raster image (JPEG, PNG) format. Can be done all in client-side.

Primary LanguageJavaScriptMIT LicenseMIT

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An easy-to-use client-side Javascript library to export SVG graphics from web pages and download them as an SVG file, PDF, or raster image (JPEG, PNG) format. Written in plain vanilla javascript. Originally created to export D3.js charts.

This library features:

  • Exporting SVG DOM Element objects or serialized SVG string to SVG file, PNG, JPEG, PDF
  • Setting custom size for exported image or graphic
  • High resolution raster image, using scale
  • Including external CSS styles in SVG
  • Filtering out parts of the SVG by CSS selector
  • Exporting text in custom embedded fonts
  • Handling transparent background for JPEG format conversion
  • Exporting SVGs that are hidden on the DOM (display: none, SVGs in hidden modals, dropdowns or tabs, etc.)
  • Exporting SVGs containing images (<image> tag)

Demo available here.

Getting Started

Prerequisites

  • Any of the following browsers: Chrome 38.0+, Edge 18.0+, Firefox 20.0+, Safari 10.1+, Opera 25+
  • Canvg (if you need JPEG/PNG export) 
    <script src="https://cdnjs.cloudflare.com/ajax/libs/canvg/3.0.9/umd.js" integrity="sha512-Wu9XXg78PiNE0DI4Z80lFKlEpLq7yGjquc0I35Nz+sYmSs4/oNHaSW8ACStXBoXciqwTLnSINqToeWP3iNDGmQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>
  • PDFKit, blob-stream and SVG-to-PDFKit (if you need PDF export). 
    <script src="https://cdn.jsdelivr.net/npm/pdfkit@0.13.0/js/pdfkit.standalone.js" integrity="sha256-41qk5dewLKulpzhP3H6G7mY+5q+vzxMaxolsOGmZD/8=" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/blob-stream-browserify@0.1.3/index.js" integrity="sha256-bFrIR3MiIsKhM2EDZdTJ3eY7iSluq1W7e6dNVwScEYw=" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/svg-to-pdfkit@0.1.8/source.js" integrity="sha256-NaOoypZxJFnz2e4IeMtA9+UMZ5Fh85ljICcUts98jqY=" crossorigin="anonymous"></script>

Please note that the CDNs above may not be the most up-to-date. The latest source code can be found directly from the github projects, also linked above.

Installation

Either download the plugin and save it in your project, or use script-tags in your html files using the hosted url.

  • Download the plugin svg-export.min.js from this repo, and add it to your project.
  • Add the plugin using the file hosted on Github Pages. Place the script within the <head> tag in your html files (place prerequisites first): 
    <!-- svg-exportJS prerequisite: canvg -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/canvg/3.0.9/umd.js" integrity="sha512-Wu9XXg78PiNE0DI4Z80lFKlEpLq7yGjquc0I35Nz+sYmSs4/oNHaSW8ACStXBoXciqwTLnSINqToeWP3iNDGmQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>
<!-- svg-exportJS plugin -->
<script src="https://sharonchoong.github.io/svg-exportJS/svg-export.min.js"></script>

Usage

Given the <svg> element:

<svg id="mysvg">...</svg>

In Javascript:

svgExport.downloadSvg(
  document.getElementById("mysvg"), // SVG DOM Element object to be exported. Alternatively, a string of the serialized SVG can be passed
  "chart title name", // chart title: file name of exported image
  { width: 200, height: 200 } // options (optional, please see below for a list of option properties)
);
svgExport.downloadPng("<svg id=\"mysvg\"></svg>", "chart title name", {
  width: 200,
  height: 200,
});
svgExport.downloadJpeg(svgElementObject, "chart title name");
svgExport.downloadPdf(svgString, "chart title name");

See index.html for an example of how to use.

Options

  • width (number) : the width of the resulting image exported, in pixels. Default is the SVG's width on the DOM
  • height (number) : the height of the resulting image exported, in pixels. Default is the SVG's height on the DOM
  • scale (number) : a multiple by which the SVG can be increased or decreased in size. For PNG and JPEG exports, if width, height and scale are not specified, scale is set to 10 for a 10x enlargement to ensure that a higher resolution image is produced. Otherwise, the default scale is 1
  • useCSS (bool): if SVG styles are specified in stylesheet externally rather than inline, setting true will add references to such styles from the styles computed by the browser. If useCSS is false, currentColor will be changed to black. This setting only applies if the SVG is passed as a DOM Element object, not as a string. Set this to false whenever possible to optimize performance. When set to true, all elements in the SVG are iterated to obtain their computed styles, which can be costly for large SVGs (please read Optimizing for large SVGs below for more detail). Default is true
  • excludeByCSSSelector (string): e.g. [stroke='red'], [stroke='green'], [display='none'], .text-muted. Elements matching the specified CSS selector will not be included in the generated file. This can be used to remove unwanted/unsupported elements of the SVG from the exported file, or to optimize performance for large SVGs. Please read Optimizing for large SVGs and Not Supported below for more detail.
  • transparentBackgroundReplace (string): the color to be used to replace a transparent background in JPEG format export. Default is white
  • allowCrossOriginImages (bool): If the SVG contains images, this option permits the use of images from foreign origins. Defaults to false. Please read Images within SVG below for more detail.
  • pdfOptions
    • pageLayout (object): e.g. { margin: 50, layout: "landscape" }. This is provided to PDFKit's addPage. When the options width and height are not specified, a minimum size of 300x300 is used for the PDF page size; otherwise the page size wraps around the SVG size. Please see the PDFKit documentation for more info
    • addTitleToPage (bool): Default is true
    • chartCaption (string) caption to appear at the bottom of the chart in the PDF. Default is no caption
    • pdfTextFontFamily (string): Font family of title and caption (if applicable) in PDF. See here for a list of available fonts. Default is Helvetica
    • pdfTitleFontSize (number): Default is 20
    • pdfCaptionFontSize (number): Default is 14
    • customFonts (array of objects): Optional argument for custom fonts. e.g. [{ fontName: 'FakeFont', url: 'fonts/FakeFont.ttf'}]. Each object must have two properties: fontName for the font name that appears in the CSS/SVG, and url for the URL of the custom font file to be used in the PDF. A third property styleName specifying the style name to be used can be specified for multi-collection font files (.ttc and .dfont files)

Custom fonts

Regarding embedded custom fonts used in the SVG element (using @font-face for example), please note that for SVG export, custom fonts only show correctly if the system opening the SVG file has the font installed. If this is not possible, please consider using one of the other file formats available.

Images within SVG

This library supports exporting SVGs that contain images in an <image> tag. If you need to export such SVGs to raster images or PDFs, please make sure that you have the latest version of Canvg and SVG-to-PDFKit. If the images' href are external, the allowCrossOriginImages option must be set to true, and the image servers must be configured with the 'Access-Control-Allow-Origin' CORS policy.

Optimizing for large SVGs

  • Set the useCSS option to false whenever possible to optimize performance. When set to true, all elements in the SVG are iterated to obtain their computed styles, which can be costly for large SVGs.
  • If you have no choice but to set useCSS to true for a large SVG, but it is causing slow performance or a frozen browser, you can also try filtering out unneeded elements within the SVG, using the excludeByCSSSelector setting. For example, you could exclude all elements in the SVG that are styled as display: none, exclude elements that have the attribute fill=transparent, or exclude unneeded elements that have a specific class name.

Colors

Colors tested to work on all exported formats include CSS color names, HEX, RGB, RGBA and HSL.

SVG graphics in Office documents

Need to add SVG graphics to Office Word, Excel or Powerpoint presentations? SVG files can be inserted as a picture for non-pixelated graphics in Office 2016 or later, including Office 365.

Roadmap

  • Open the generated file in a new window/tab instead of downloading the file
  • Set up package.json and publish to npm (jsdom for Node?)

Not Supported

Since foreignObject does not contain SVG, it is not supported.

Contributing

Contributions are very welcome! Feel free to flag issues or pull requests.

License

Licensed under MIT. See LICENSE for more information.

Contact

Sharon Choong - https://sharonchoong.github.io/

Send me your cheers with a cup of coffee! Ko-Fi