Inline SVG extension

Following is a very simple piece of work. Feel free to comment, particularly about alternative approaches and so on.

Purpose & Quick Howto

To enable including in-line svg code in a wiki document, using client browser's capability (native as in mozilla firefox or with a plug-in as in internet explorer and Adobe's SVG plugin).

Do I need this extension

Probably not! You can achieve the same results using standard mediawiki tools

• Upload the svg file as an image
• Then use it in an [[Image:foobar]] tag. It works for many browsers.

And if you want to play it safe (remember many old browsers might not support svg format!)

• Use SVG Extension by User:Coffman. It renders gif or png directly, which works in every browser.

Howto

Follow the steps below:

• Cut and paste the source code below in to a file named SVGtag.php in your extensions directory
• Call SVGtag.php by adding following line to the end of LocalSettings.php

  include("extensions/SVGtag.php");

• Include svg code as follows:

  <svgcode calling_arguments>

<svg various arguments come here> svg code here </svg> </svgcode>

• • For example

    <svgcode width="300" height="200" version="1.1">

<svg version="1.1" id="Layer_1" xmlns="&ns_svg;" xmlns:xlink="&ns_xlink;" width="300" height="200"

    viewBox="0 0 300 350" >

<rect x="0.5" y="0.5" fill="#FFFFFF" stroke="#000000" width="250" height="175"/> </svg>

</svgcode>

See the bottom of this article to see whether your browser support svg.

Background

See Also: SVG

In a perfect world, there is no need to use fancy method to incorporate a SVG script to a web page. However, the conflicts in various browser standards make the waters muddy. There are several methods to do this, depending on targeted browser, but nothing works perfectly for everything[1]. The best compromise seems to be having the svg code in a separate file and include that file in a special object/embed/iframe tag. the latter seems to work best in both worlds (i.e. Mozilla, native svg rendering and IE assisted by Adobe SVG plug in.

<iframe src="file.svg" width="500" height="500">
</iframe>

can show a properly formatted svg file in most of the modern browsers.

How it works

(see metawikipedia:Write_your_own_MediaWiki_extension first.)

• The extension registers a hook to Mediawiki wgParser requesting it to run returnSVGtagged function whenever

  <svgtag> blah blah </svgtag>

  is found in the code, using 'blah blah' (code between <svgtag> and </svgtag> as the argument.
• returnSVGtagged function does the following
  1. Creates a unique file name based on MD5 checksum of the svg code in the argument.
  2. Checks whether a file by that name exists
  3. if no
     1. create a new file under that name with svg code as argument
  4. end if
  5. return a iframe tag calling the unique file name.

Source Code

<?php
#----------------------------------------------------------------------------
#Copyright 2006 Assela Pathirana
#----------------------------------------------------------------------------
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#-------------------------------------------------------------------------------
#    Inspired by svgextension.
#-------------------------------------------------------------------------------
$wgExtensionFunctions[] = "wfSVGtag";

function wfSVGtag() {
	global $wgParser;
	$wgParser->setHook( "svgcode", "returnSVGtagged" );
}

function returnSVGtagged( $code, $argv)
{
	global $wgUploadDirectory, $wgUploadPath, $IP, $wgArticlePath, $wgTmpDirectory;
	$hash = md5( $code );
  $tmploc="/svgcode/";
  $extension=".svg";
  $svgversion=$argv["version"];
  $boxwidth=$argv["width"];
  $boxheight=$argv["height"];
  if (!is_numeric($boxwidth)){
    $boxwidth="500";
  }
  if (!is_numeric($boxheight)){
    $boxheight="500";
  }
  if ($svgversion==""){
    $svgversion='1.1';
  }
  $svgversion2=str_replace(".","",$svgversion);
  $dest = $wgUploadDirectory.$tmploc;
  $path= $wgUploadPath.$tmploc;
	if ( ! is_dir( $dest ) ) { mkdir( $dest, 0777 ); }
	if ( ! is_dir( $wgTmpDirectory ) ) { mkdir( $wgTmpDirectory, 0777 ); }

	$outfile = $dest . $hash.$extension;
  $pname = $path . $hash.$extension;
	if ( !  file_exists( $outfile ) ) {
		$ptr = fopen($outfile, "w");
    $header=
    '<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG '.$svgversion.'//EN" "http://www.w3.org/Graphics/SVG/'.$svgversion.
    '/DTD/svg'.$svgversion2.'.dtd" [ <!ENTITY ns_svg "http://www.w3.org/2000/svg">'.
    '<!ENTITY ns_xlink "http://www.w3.org/1999/xlink"> ]>';
		fwrite($ptr, $header);
		fwrite($ptr, $code);
		fclose($ptr);
  } 
 		$txt  = "<iframe src=$pname width='".$boxwidth."' height='".$boxheight."' ></iframe>";
    return $txt;
}

?>

SVG Browser Test

Well.. you should be ablve to see the images below, even if your browser dosn't support svg. They were uploaded using the Image: directive of mediawiki, so that what you see here are actually png images generated by the host at upload time. To do the real test, click on one of the images to go to the image page and click on the url with .svg extension, below the image on that page. Then, if you see a rectangle, then your browser really supports svg! (shortcut: just clik here and here.