Scalable vector graphics is a commonly used file format for providing a geometrical description of an image using basic objects such as labels, circles, lines, curves and polygons. An image can be reduced or enlarged to an arbitrary size, and will not suffer image data loss, nor will it become pixelated. SVG makes an excellent format for artwork, diagrams and drawings. SVG images are defined in XML text files. This means that they can be searched, indexed, scripted and, compressed. Since they are XML files, SVG images can be edited with any text editor, but SVG-based drawing programs are also available.
However, the rendering engine used by wiki is not perfect, and may cause the image to be shown incorrectly, or differently from how it is displayed in your vector editor of choice. This page enables authors experiencing problems with SVG graphics to obtain some help in getting their images into wiki the way they intend.
Things that can be helped with on this page
Using SVG appropriately
What you see is not what you get
Missing objects or black boxes
Failure to convert these objects appropriately, which is often not user error, may lead to incorrect Z-ordering, phantom black boxes or missing (not rasterized) objects. If operating on a system with rsvg installed (based on the librsvg library which is used by Wikimedia to rasterize SVG files), it may be a good idea to check the image before uploading to MediaWiki servers. If black boxes still appear after converting all objects appropriately, it may be necessary to hand-edit the XML to remove the <flowroot> tags.   The issue seems to stem from a mismatch between SVG 1.2 and SVG 1.1 behaviour, and affects several 1.1 programs, such as rsvg. The workarounds that one can employ are either not to use flowed text (by using the text tool without creating a text field), or to stroke the text using "object to path". This can subsequently (and optionally) be cleaned up using "simplify", although this has the negative side effect of smoothing your fonts, particularly at sharp corners. The positive effect of the simplify step is to significantly reduce the filesize required to describe your text components.
Due to copyright restrictions, MediaWiki cannot use proprietary fonts that are commonly found on several proprietary operating systems. Fonts such as Geneva require licensing fees to distribute. rsvg will not be able to locate such fonts, and the text will fail to appear in the rendered image. There are three solutions to this issue:
For ease of subsequent editing and significantly smaller file sizes, substituting the font with an available font is the recommended option. Many of the common fonts have non-proprietary alternatives that are somewhat similar in typographical style, resulting in minimal disruption to existing images during substitution. For a list of fonts available in Wikipedia, see available fonts on Meta.
Here are some suggested freely-distributable replacements for commonly-used proprietary fonts:
Fonts which are available on Wikimedia servers may or may not be available on a visitor's machine. If the placement or appearance of text in the image is important and there is uncertainty about which fonts are installed on a visitor's machine, then converting text into path information (as mentioned hereinbefore) may be necessary.
MediaWiki provides rasterized previews of SVG images. If those are only images needed by a visitor, then no portability issues may arise. If the visitor retrieves the SVG image to render it directly in their browser (perhaps to zoom in and see more detail than provided in MediaWiki's rasterized preview), it may not display as intended unless the referenced fonts have been installed on the visitor's machine.
Some fonts like Times and Helvetica have problems with resizing, replacing them with Liberation Serif and Liberation Sans, respectively, should fix the issue.
Missing embedded JPEG images
When a raster graphic is embedded in an SVG it is encoded into base64 data. That data is then assigned a MIME type in the <image> element. In the case of an embedded JPEG, the MIME type is "image/jpeg". Older versions of Inkscape (and possibly other editors) assigned the MIME type "image/jpg". While Inkscape and most web browsers will display such an SVG image just fine, the MediaWiki software that rasterizes the SVG file will have trouble with it. Not recognizing the MIME type "image/jpg" there will simply be an empty space where the image is supposed to be. The fix is to open the SVG file in a text editor, find the <image> element, locate "image/jpg", change it to "image/jpeg" and re-save. At right is an example of this problem.
MediaWiki (the software from which Wikipedia is run) uses the librsvg-library to rasterize all of its svg files. The version of the rsvg program that is installed on wiki does not always correctly raster the Inkscape or OpenOffice.org SVG files. The file manager GNOME Files relies on librsvg, so it can be used to check the quality before a SVG is uploaded.
Rendering Inkscape files
There is a simple work-around for the scarcities of librsvg. The operation "Stroke to Path", to be found under Menu>Path in Inkscape or via Ctrl+Alt+C, can be applied to all of the objects that are not rendered correctly. To keep the SVGs editable, this should only be done to the files intended for upload, and these files can be deleted afterwards.
As of February 2014, the objects that must be modified to render correctly by libsrvg include:
Rendering OpenOffice.org SVG files
OpenOffice.org SVG files may require manual modification before being uploaded to Wikipedia. To achieve this:
NB: Vector graphics line widths may also need to be set explicitly in OpenOffice.org Draw.
SVG code replacement guide (executing replace all using Nedit regular expressions)
This SVG export procedure has been tested using OO 2.3.0 and OO 3.2.1 with a simple .odg candidate.
- 1 Common problems
- 2 Rendering files
- 3 Assistance
- 4 Current requests
If you have a tricky SVG file with a problem not described, or can't quite figure out what the previous section was talking about, you can simply ask for assistance by posting a quick note hereafter that outlines the problem, as well as providing links to the files that are exhibiting these problems. Don't forget to sign your name with four tilde symbols (~~~~) and an editor will attempt to reply here to help!
When you are happy that a request has been fulfilled, just leave a note so that the request can be archived later, as needed.
An alternative source of help is Commons:Graphics village pump.