Commons:Commons SVG Checker/KnownBugs

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Checks

[edit]

The checks are described in the JavaScript source file, which is found at MediaWiki:CommonsSvgChecker.js. As of July 2018, Wikimedia servers are using librsvg-2.40.16.

The checks include those for the following bugs
Other problems exist but are not checked.
  • Text ignores alignment-baseline attribute. File:SVG Test TextAlign.svg
  • GNOME #249; Text with direction="rtl" mishandles text-anchor. For example, RTL text with an anchor of start should begin at the specified location and develop to the left. File:SVG Test TextAlign.svg
  • Text with tspan and differing text-anchor attributes must have absolute position change required by SVG 1.1. (The SVG 1.1 layout rules say an absolute position change creates a new text chunk for layout; text-anchor is done within a text chunk. A relative position change does not create a new text chunk, so a text-anchor change would be ignored.)
  • Text uses wrong baseline for Arabic. The Arabic baseline (e.g., ليالي العرب) is higher than the Latin baseline.
  • Phab:T25643; SVG specifies font's PostScript name (e.g., font-family="Helvetica-Bold") rather than a separate family and weight (e.g., font-family="Helvetica" font-weight="bold"). Checker will flag the font file as an unknown font. This problem is common with Adobe products and Macintosh systems.
  • Phab:T36947; There is a small font size quantization issue. File:StrekenProvincieUtrecht1.svg
  • Phab:T43423; CSS child selectors are not supported by librsvg.
  • Phab:T68551; CSS classes on text elements are not inherited by child tspan elements. If you want this, you need to add a separate class for tspan as well, or use simply groups (but not in the text element as it Scour unfortunately does).
  • Phab:T64987, Phab:T184369, Gnome #95; font-family="'font name'" (internally quoted font family name) does not work (File:Mathematical_implication_diagram-alt.svg, File:T184369.svg)
  • fonts such as "Sans" are not generating warnings despite being in a list:
    var gFontSubstitution2 = [ "sans", "Sans", "Serif" ];
    Try, for example, File:MenstrualCycle ca.svg: check
  • xlink:href attribute; may not reference external resources in most elements. For example, an external resource may be referenced in a elements, but not in use elements. https://www.w3.org/TR/SVG11/linking.html#IRIReference
  • <use transform="matrix(-1 0 0 -1 0 0)" xlink:href="#a"/> does not work if it is mirrored two times (-1): File:Labanotation2.svg
  • <feGaussianBlur> seems to be a bit different from browsers: (f.e. File:Oxygen480-status-weather-clear-night.svg, File:Mahuri.svg, File:Pittsburgh_newspaper_consolidation_timeline.svg)
  • Librsvg_bugs#Pattern on small scales (f.e. File:Pong.svg, File:Languages-Europe_edit.svg)
  • tref is in SVG 1.1, but it is not supported by most user agents (including librsvg) and is removed in an SVG 2.0 candidate recommendation. See SVG 2.0, W3C Candidate Recommendation 15 September 2016, "Appendix L: Changes from SVG 1.1", https://www.w3.org/TR/SVG2/changes.html
  • Phab:T88833, Gnome #108 (fixed in 2.42.3); librsvg does not do the CSS 2.1 style font-size: smaller (relative size change)
  • librsvg does not do the CSS 2.1 style text-transform: uppercase (uppercase/lowercase/capitalize string)
  • SVG 1.1(2nd) font-variant="small-caps" not supported. File:SVG Test TextAlign.svg
  • GNOME #131, GNOME #256; systemLanguage errs with hyphenated languages
  • GNOME #88; textLength not supported. File:SVG Test TextAlign.svg
  • Phab:T60920 Semantics of lang parameter are confused.
  • Phab:T200443 A text element with a text-anchor of "middle" or "end" may not work if there is a tspan element with x or y attributes followed by a #text node.
  • librsvg does not render a element children of text element.
  • MW blocks upload of a elements with href attribute (SVG 2.0) (see https://www.w3.org/Graphics/SVG/WG/wiki/Href); MW permits upload of a elements with xlink:href attribute (SVG 1.1).
  • Phab:T228321 librsvg < librsvg2-2.45.6 does not like single quotation marks in functURLs that are used in, for example, gradient fills. Instead of fill="url('#ident')" use fill="(#ident)". See File:SVG Gradient.svg.
  • Phab:T228325 GNOME #48 librsvg gradient fills using gradientUnits="userBoundingBox" (the default) in rotated user space do not work correctly. See File:SVG Gradient.svg.
  • Phab:T270889 MW may not detect systemLanguage attributes in large SVG files. By default, MW only scans the first $wgSVGMetadataCutoff = 256 kB[1] of an SVG file, so MW may incorrectly conclude the file does not have translations, or MW may omit some languages from the language dropdown. See File:Antarctica.svg.
  • Phab:T217990 librsvg does not parse path elements with arcs correctly. SVG arcs have single-character flags that do not need to be separated with commas or spaces, but librsvg needs the separators. Consequently, arcs in the illustration may start in the expected place, but they may have an odd shape and finish somewhere unexpected.
  • Phab:T276684 A use element xlink:href links to another use element.
  • phab:T304190 SVG 1.1 requires image elements to have the height and width attributes. If those attributes are not present, then librsvg does not render the image and stops further rendering. A validation using the SVG 1.1 DTD will detect this error.
  • SVG 1.1 symbol elements with style="overflow:visible" will not work if they draw outside of their viewBox. The SVG 2.0 symbol attributes refX and refY are not supported.
  • Commons restricts SVG files to a small set of whitelisted XML namespaces.
  • A clipPath element should only contain simple shapes such as rect, circle, and path. Inkscape will add g elements that will cause librsvg and modern renders to display nothing. (Old versions of rsvg tolerated g elements, but new versions (and most browsers) do not. Consequently, some older files on Commons no longer display as expected.)
Commons SVG Checker does not look for potential problems with SVG Translate. (See also Phab:T250330.)
  • SVG Translate does not work when CSS ID selectors are used: Phab:T221382
  • SVG Translate does not work when CSS ends abruptly: Phab:T271595
  • SVG Translate does not work when the text elements have differing numbers of tspan elements.
  • SVG Translate does not handle deeply nested tspan elements (e.g., subscripts, font changes, or color changes).
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