SVG help

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 we can help with

Understanding SVG

Questions about the SVG format

Using SVG appropriately

When to (or not to) use SVG

What you see is not what you get

Missing objects from files
Random filled boxes in the image
Images that are the wrong size
Font inconsistencies
Other weird and wonderful bugs

Something new

Questions that you can't find a better place for

General suggestions

The following is a list of common vector editors and suggested settings for compatibility. The user guide of your chosen program may also be valuable in troubleshooting.

Browsers

Most modern browsers can render SVGs in view-only mode. It may be convenient to set a browser as the default SVG viewer, but you can also paste the file path into the address bar. Please note that even if your browser renders an SVG correctly, it may render differently on Wikipedia.

Text editors

SVG documents are text files, and can be edited like any other text file. Specifically, SVGs are XML documents, which have special support in many text editors. One potential disadvantage to editing SVGs by hand is that previewing your changes is more cumbersome. A rudimentary solution would be to open the SVG file in a browser while working on it, and manually refreshing the document to see the result of changes.

Inkscape

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 librsvg include:

Lines with arrow heads (the arrows need to be converted)
Text, that has been transformed, e.g. "Text on Path"
Compound objects created with the binary path tools (union, intersect etc.)

OpenOffice.org

OpenOffice.org SVG files may require manual modification before being uploaded to Wikipedia. To achieve this:

Change all fonts to Wikipedia supported fonts as mentioned before. (E.g. change "Sans embedded" to "DejaVu Sans".)
Add "px" to all font-size references. (E.g. change "font-size:100" to "font-size:100px".)
Remove all additional x coordinate references in tspan elements. (E.g. change <tspan x="17583 17917 " y="10943"> to <tspan x="17583" y="10943">.)
[Not required for OO 2.3.0] Explicitly colour all text (e.g. black) by replacing relevant "stroke:none;fill:none" instances with "stroke:none;fill:rgb(0,0,0)" (note that simply explicitly colouring text black in OpenOffice 3.2.1 does not appear to work).

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)

Original text	Replacement text
Sans embedded	DejaVu Sans
`tspan x="([0-9]) ([0-9 ])"`	`tspan x="\1"`

This SVG export procedure has been tested using OO 2.3.0 and OO 3.2.1 with a simple .odg candidate.

Microsoft Powerpoint

It is easiest to save entire slides from Powerpoint as svg rather than saving multiselected objects with right click / save as picture, because for entire slides the boundaries will be cropped to the size of the slide and the background will be set to white. To save slides as svg, use file / save as / browse / save as type --> svg.

If your slide has text, open the exported svg into Notepad and replace all the existing font-family specifications with font-family="Liberation Sans,sans-serif". This specification will make Wikimedia render SVG fonts similarly to how browsers render Wikipedia fonts.

Text can also get chopped up on export, which causes rendering and localization bugs. To fix this, search for all </text> tags and make sure the tag isn't embedded in another text tag that's on the same line of text. Most embedded text tags can simply be deleted; however, but if content needs to be subscripted or subscripted, then replace the text tag with a tspan specifiction. For subscripts, use <tspan font-size="smaller" baseline-shift="sub">. For superscripts, use <tspan font-size="smaller" baseline-shift="super">.

Microsoft Visio

Generating SVG charts from Microsoft Excel

Warming stripes
(five examples compared)

Warming stripes bar chart

Bar chart (vertical)

Pie chart

Line charts

Scatterplot

I've uploaded .xlsx (Microsoft Excel) spreadsheets that automatically generate XML code for charts in SVG format.

You simply paste or enter your data into the spreadsheet, and specify image dimensions, number of grid lines, font sizes, etc. The spreadsheet instantly and automatically generates a column of XML code that you simply copy and paste into a text editor and save as an ".svg" file. The spreadsheets produce lean SVG code, avoiding the "extra stuff" that Inkscape inserts. They should save you time in creating SVG charts.

Feedback and suggestions on my talk page are welcome. RCraig09 (talk) 23:41, 19 February 2021 (UTC)[reply]

Click HOW TO for detailed explanation.

Click HERE (else HERE) to download the spreadsheets.

Example SVG files: Category:SVG diagrams created with spreadsheet.

Warming stripes — Accepts a single dataset and converts to SVG code portraying Ed Hawkins' warming stripes graphics. User chooses vertical or horizontal stripes; normal or reverse data ordering; or from a variety of geometric shapes (updated 17 May 2023). . . . . Click here to see examples of warming stripes embedded in different shapes.
Warming stripes bar chart — Accepts a single dataset and creates a conventional bar chart whose individual bars/columns are coloured according to Dr. Hawkins' warming stripes colour scheme. Alternate option: choose one colour for ascending bars and another colour for descending bars. (updated 28 August 2023)
Line charts — Accepts up to six datasets. (updated 30 August 2023)
Vertical bar charts (column charts) — Accepts up to six datasets. Toggle between clustered and stacked charts; user can adjust "Yfloor"—the Y level (usually=0) from which columns rise or fall; user chooses to keep or ignore negative input values. (updated 27 August 2023)
Horizontal bar charts — Accepts up to six datasets. Toggle between clustered and stacked charts; user can adjust "Yfloor"—the value (usually=0) from which bars extend; user chooses to keep or ignore negative input values. (updated 27 August 2023)
Scatter plots — Accepts up to five datasets. (updated 28 August 2023)
Pie charts — Accepts a single dataset of up to 36 items. (updated 17 May 2023)
Variable-width bar charts — Accepts up to six datasets; is like "Vertical bar charts", above, but user can choose different widths for different bars. (updated 27 August 2023)

Text guidance

Use text over paths

Converting text in an SVG file into paths (shapes) increases file size, prevents localization/accessibility features, and complicates edits/modifications down the line. It is therefore generally disfavored, with some exceptions, such as text-based logos. The Wikimedia text renderer can introduce bugs as its fonts may differ from browser fonts or SVG editor fonts, but following the guidance below should minimize these errors.

font-family property

Tracked in Phabricator
Task T180923

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:

One can substitute a font that is available on Wikipedia. This approach facilitates editability.
One can specify a generic font-family such as "sans-serif", "serif", or "monospace", but this can lead to inconsistent rendering. It is better to specify a font available on Wikipedia (such as Liberation Sans) with fallback fonts such as: font-family="Liberation Sans,Arial,Helvetica,sans-serif", in which you define a font-list with similar fonts that at least contain one font for each Operating System such as Wikimedia (e.g. Liberation Sans), Windows (e.g. Arial), Linux (e.g. Liberation Sans), Mac (e.g. Helvetica).
Since local rendering should be as close as possible to Wikipedia, it should use locally the same font as it will have on Wikipedia, if available. Therefore always define a Wikimedia-font first. Also, Wikimedia has synonyms for substituting fonts, such as "Arial" for "Liberation Sans"; therefore font-family="Arial,DejaVu Sans" will be rendered by "Liberation Sans" and not (as expected) by "DejaVu Sans". (This is because "Liberation Sans" has the same letter size as "Arial" [metric-compatible], so it is less likely to mess up the text flow.)
Group the text, create a copy, and convert the copy to paths. Then either:
1. move the original, editable non-path text into a separate editable text layer that you make transparent (warning: this might be removed by SVG optimizers), or
2. move the original, editable non-path text outside the visible area (example: File:Essigsäuresynthesen.svg).

For ease of subsequent editing and significantly smaller file sizes, substituting the font with an available font is recommended. Many common fonts have non-proprietary alternatives that are 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.

Wikimedia has default fonts, and will use Liberation Serif for Times New Roman and Liberation Sans for Arial. For further fallbacks see c:Help:SVG#fallback.

Fonts that 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 may be necessary.

font-size property

Fonts should be sized so that they look good as thumbnails on wikipedia pages and so they are easy to view on smartphones. Smartphones are how most people access wikipedia. Thumbnails are how most other people see images, as very few people click images and zoom them in to see them. Avoid using or creating images with fonts that are too small to be legible in thumbnail or smartphone views.

The font size that appears in a thumbnail is a combination of svg width, thumbnail width, and font size. To match wikipedia font size as a thumbnail, use font-size = (63/(your upright value))*((your svg width)/1000). For instance, if the thumbnail will be scaled up to thumb upright=1.35 and your image has svg width of 960, set font-size in the svg to (63/1.35)*(960/1000) = 44.8.

Background colors

Transparent backgrounds are fine, but do not think your image will always be displayed on a light or white background. The wikipedia smartphone app, for instance, renders images on a black background, so if you show black text on a transparent background it will be invisible.

Testing for problems

The following SVG checkers may help you to detect SVG problems before you upload:

None of these checkers are foolproof, so it's wise to validate images. You can preliminarily validate images by uploading them to the shared, temporary-use location Test.svg, though other users may overwrite your image at any time.

To force refresh images in your browser use Ctrl+F5 (Shift-Reload on Mac), so that you see the latest upload and not cached image copies (this is necessary even on wikimedia upload pages).

Rendering SVG files

On Wikipedia SVGs are interpreted by the librsvg-library to create PNG previews at different image sizes (to rasterize them). That library only recognizes a subset of all valid SVG syntax, and may render your SVG without many features.

In order to bypass these deficiencies in the library, there are certain parameters that need to be formatted in specific ways or be assigned a workaround value in order for librsvg to accurately render views of your SVG file. Some issues are enumerated below, but be sure to test your SVG files before and after uploading them.

<mask> parameter maskUnits="userSpaceOnUse"

The librsvg-library does not interpret the value of "userSpaceOnUse" for the parameter maskUnits correctly. To bypass this issue, replace maskUnits="userSpaceOnUse" with maskUnits="-10% -10% 120% 120%", and the SVG mask will render properly on Wikipedia.

parameter stroke-dasharray

The librsvg-library does not accept a stroke-dasharray parameter with values separated by spaces. Replace all spaces with commas to bypass this issue:
Example: replace stroke-dasharray="2 3 2 4" with stroke-dasharray="2,3,2,4"

Use `href=` alone, not `xlink:href=`, in `<use ___/>` statements

xlink:href was deprecated and replaced by href in SVG 2, released in 2018. Between 2023 and 2024, Wikimedia's SVG renderer has been updated to follow suit, so xlink:href no longer works. Instead, href should now be used.

CSS selectors or identifiers must start with a letter or hyphen

http://w3.org/TR/css-syntax-3 states, "Property names and at-rule names are always identifiers, which have to start with a letter or a hyphen..."

Common problems

Misaligned text

Tracked in Phabricator
Task T97233

The latest thumbnail-image-maker (named rsvg) unfortunately has a bug which misaligns centre- or right-aligned text tags containing tspan tags on the same line.

While developers work on a solution, here are some remedies in decreasing usefulness:

Left-align affected text tags with text-anchor="start"
Specify either the y or dy attribute for affected tspan tags
If using multiple tspan tags on a line for:
- word and character spacing, use:
  1.   (non-breaking space),   (thin space) and/or   (hair space) characters
  2. the letter-spacing attribute
  3. a monospaced font such as Liberation Mono (last resort)
- subscripts or superscripts, use Unicode subscripts and superscripts
- bolding or italicizing variables etc in mathematics, use Unicode Mathematical Alphanumeric Symbols
Merge affected tspan tags, even unitalicising variables etc if above methods fail
Convert text into shapes (last resort, as the text can no longer be amended, copied or read by screen-readers)

flowRoot does not appear

a picture containing SVG1.2-valid flowRoot

Tracked in Phabricator
Task T43424
Declined

If a black box appears, read c:User:JoKalliauer/RepairFlowRoot how to solve this issue, but do not remove those objects since they might contain text. The workarounds that one can employ are either not to use flowed text (by using the text tool without creating a text field), or convert the text to normal text (by Text-editor or sed-command, or with Inkscape-GUI or with a Inkscape-batch), but to stroke the text using "object to path", since path-text is not recommended and increases file-size.

Missing embedded JPEG images

Tracked in Phabricator
Task T193929
Invalid

Normal image

Broken image

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. The Commons SVG Checker looks for this problem; see Commons:Commons:Commons SVG Checker/KnownBugs#Checks for details.

Though Web browsers cope with image tags without width and height specified, librsvg ignores such images.

Further issues

Further issues can be found at c:Librsvg_bugs or at Commons:Commons:Commons SVG Checker/KnownBugs, and examples can be found at c:Category:Pictures_demonstrating_a_librsvg_bug. However most issues (for files <1MB) can be fixed using https://svgworkaroundbot.toolforge.org/ (enable "run svgcleaner" and enable "run scour" before clicking convert), for a more detailed list check c:User:SVGWorkaroundBot.

Assistance

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.

Current requests

Archives

This page has archives. Sections older than 30 days may be automatically archived by when more than 4 sections are present.

Create a new request

rsvg not respecting fill-opacity:0 in style tag

When http://upload.wikimedia.org/wikipedia/commons/0/0a/Chord_intervals.svg is opened in Firefox, Chrome or Edge, chords in the key of C are shown by default. Hovering over the grey buttons at the bottom changes the chords. The output from http://svgcheck.toolforge.org concurs.

However, in the thumbnail here, all note names appear at the same time, even though .active, .default:hover { fill-opacity:0; } makes their opacities zero unless hovered over.

Would someone be able to look into this, please?

Thanks, cmɢʟee⎆τaʟκ 00:35, 13 October 2024 (UTC)[reply]

@Cmglee: What you have displayed here is not an SVG but the PNG representation of an SVG, it has no concept of hover. --Redrose64 🌹 (talk) 08:47, 13 October 2024 (UTC)[reply]

@Cmglee: I think the problem is that Wikipedia converts the SVG to various sized PNGs for use in thumbnails. See Wikipedia:SVG help#Rendering SVG files. This long-standing issue was initially a fix for browsers that didn't support SVGs; it will hopefully be fixed at some point in the future! Aluxosm (talk) 10:50, 13 October 2024 (UTC)[reply]

Thanks, @Redrose64: and @Aluxosm:

Having uploaded over 2000 SVG illustrations over 15 years (about 3 a week), I'm aware that rsvg rasterises SVG into PNG, which I think should not react to hover events.

What I'm asking is why rsvg renders all the note names overlapping (note the black blobs) instead of only one showing in the left and right columns, and the bottom row, as all except that one have class set to active which has fill-opacity:0 unless it also has a hover selector (.active:hover) Is it because the current rsvg triggers hover for all of them? SVG Check in toolforge does not have this behaviour.

Thanks, cmɢʟee⎆τaʟκ 19:43, 13 October 2024 (UTC)[reply]

Some years ago, I determined that within style sheets (which we can only supply in the form of CSS rules enclosed inside <style type="text/css">...</style> tags), librsvg can only recognise tokens that are explicitly defined in either CSS Level 1 or SVG Version 1.1, and the :hover pseudo-class is not defined in either of these - it is first described in CSS Level 2. Now, user agents are instructed to skip a rule if any of its selectors is illegal, so effectively the style sheet is treated as if two rules were commented out:

<style type="text/css">
svg { font-family:'Liberation Sans',Helvetica,Arial,sans-serif; font-size:16px; letter-spacing:-1px; text-anchor:middle; fill:#000; pointer-events:none; }
.trigger                { pointer-events:auto; }
/* .active, .default:hover { fill-opacity:0; } */
/* .active:hover           { fill-opacity:1; } */
.interval               { fill:none; stroke-width:1.5; }
 </style>

so for elements belonging to the active class, the fill-opacity property will take its initial value, which is 1. So all of that text is drawn in black, and it overlaps, giving the black blobs. --Redrose64 🌹 (talk) 20:43, 13 October 2024 (UTC)[reply]

Thank you very much for your thorough explanation, @Redrose64: I'll see if I can work around it. Cheers, cmɢʟee⎆τaʟκ 21:12, 14 October 2024 (UTC)[reply]

Resolved

cmɢʟee⎆τaʟκ 10:20, 25 October 2024 (UTC)[reply]

Transformed masked object does not appear

In this SVG, I applied a mask on a semi-transparent object and then translated, and also scaled it (to get the half-faded mirages).

It appears correctly in http://svgcheck.toolforge.org/index.php , Firefox, Chrome and Edge but not in the rsvg thumbnail.

Is this a known issue? Could someone please suggeset a workaround?

Thanks, cmɢʟee⎆τaʟκ 23:25, 19 November 2024 (UTC)[reply]