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"ImageMagick" SVG converter shouldn't use "-background white", but "transparent"
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"ImageMagick" SVG converter shouldn't use "-background white", but "transparent". No idea why this is done this way, changing it didn't break anything for me, but I assume there's a reason. Right now we can't rasterize SVGs for T76473 without losing transparency…

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matmarex created this task.Dec 2 2014, 3:31 PM
matmarex raised the priority of this task from to Needs Triage.
matmarex updated the task description. (Show Details)
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matmarex added subscribers: Bawolff, aaron.
Gilles triaged this task as High priority.Dec 2 2014, 4:23 PM
Gilles moved this task from Untriaged to Prototyping on the Multimedia board.
Gilles added a subscriber: Gilles.

Possible guess (without looking at code): work around ie6 png transparency bug. -background controls both the rendering background and the png fallback if alpha not supported background.

If that is the case, i believe its possible to specify both independently using the switch multiple times.

Can you do that, please? Or anyone? Please? :)

matmarex claimed this task.Feb 5 2015, 7:15 PM

I did some research and experimenting. Brian's guess seems correct and his proposed solution seems to work.

I took this SVG file:

(source:, uploaded to a testing wiki and rasterized with the following options in $wgSVGConverters['ImageMagick']:

  • -background white: F37591 – result: opaque white background
  • -background transparent: F37593 – result: transparent background, renders as solid black square using IE6 on WinXP
  • -background "#ffffff00": F37595 – result: transparent background, renders with opaque white background using IE6 on WinXP

So, here's a patch to change the default to the last version.

gerritbot added a subscriber: gerritbot.

Change 188857 had a related patch set uploaded (by Bartosz Dziewoński):
Use transparent rather than white background for ImageMagick SVG thumbnails


matmarex lowered the priority of this task from High to Normal.Feb 5 2015, 7:19 PM

Change 188857 merged by jenkins-bot:
Use transparent rather than white background for ImageMagick SVG thumbnails

matmarex closed this task as Resolved.Feb 5 2015, 8:01 PM
matmarex removed a subscriber: gerritbot.