Compass SVG polyfill

A compass plugin which serves SVG background images to new browsers and provides a PNG fallback to old browsers.

Project details

Use case

SVGs are great as they're a vector format but some browsers don't support them. This script automates the conversion of SVGs to PNGs and provides the CSS for you.

Problem domain

Requirements

In order to use this gem you must have either ImageMagick or librsvg.

ImageMagick is the recommended library.

Mac OS X Installation

ImageMagick

Install ImageMagick

brew install imagemagick

librsvg

Download and install XQuartz

https://xquartz.macosforge.org/landing/

Install librsvg

brew install librsvg

Linux Installation

Tested on Ubuntu 12.04 and Ubuntu 14.04

ImageMagick

Install ImageMagick

sudo apt-get install imagemagick libmagickwand-dev graphicsmagick-libmagick-dev-compat
sudo apt-get install libmagickcore-dev libmagickwand-dev

librsvg

Install librsvg

sudo apt-get update
sudo apt-get install librsvg2-bin

Usage

Instructions

The following instructions are for adding the SVG background image code to an existing project.

Install gem

gem install compass-svg-polyfill

Add the following to the top of your config.rb:

require "compass-svg-polyfill"

Run compass

compass watch

Add your stylesheet:

# At the top of your file
@import "compass-svg-polyfill/svg";

# Optionally, define the default image converter
$default-image-converter: imagemagick;

# Target a specific element
.element {
    @include background-svg(
        $width: 856px,                  /* value must be in pixels */
        $height: 433px,                 /* value must be in pixels */
        $svg: "world-map.svg",          /* file must exist */
        $png: "world-map-856x433.png",  /* file to be generated */
        $inline: false,                 /* optional: include svg in css */
        $image-converter: librsvg       /* optional: imagemagick or librsvg */
    );
}

When using compass watch images are regenerated every time you update your CSS files. If you make changes to your SVG images, resave a stylesheet containing the image and the PNG images will be regenerated.

$inline

  • Optional
  • Default value: false
  • Available from: 1.0.4

The SVG vector images can be base64 encoded and included in the CSS output through a data URI. The fallback PNG images are linked through a URL.

This means that on older browsers the load time is slightly slower (because you have to download two files) but on more modern browsers you have limited the number of HTTP requests.

When true: SVG images are encoded in the CSS file and PNG images download via a separate HTTP request

When false: both SVG and PNG images are downloaded via a separate HTTP request

$image-converter

  • Optional
  • Default value: imagemagick
  • Valid values: imagemagick, librsvg
  • Available from: 1.0.5

You can select which image converter to use on a case-by-case basis using this parameter.

Global variables

$default-image-converter

  • Global
  • Optional
  • Default value: imagemagick
  • Valid values: imagemagick, librsvg
  • Available from: 1.0.5

Select which image converter to use globally.

Licence

Copyright (C) 2013, Bashkim Isai

This script is distributed under the MIT licence.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Contributors

If you fork this project and create a pull request add your GitHub username, your full name and website to the end of list above.