Last modified: 2014-10-06 06:21:42 UTC

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Bug 16368 - [SVG Rendering] Worsening of font rendering quality
[SVG Rendering] Worsening of font rendering quality
Status: REOPENED
Product: Wikimedia
Classification: Unclassified
SVG rendering (Other open bugs)
unspecified
All All
: Normal minor with 5 votes (vote)
: ---
Assigned To: Nobody - You can work on this!
: testme
Depends on:
Blocks: svg
  Show dependency treegraph
 
Reported: 2008-11-17 11:47 UTC by Alexander Karnstedt
Modified: 2014-10-06 06:21 UTC (History)
7 users (show)

See Also:
Web browser: ---
Mobile Platform: ---
Assignee Huggle Beta Tester: ---


Attachments
Comparison of rendering by User and by MediaWiki (690.14 KB, image/png)
2010-01-04 17:54 UTC, Guillaume Paumier
Details
another SVG rendering comparison (Liberation Sans) (59.56 KB, image/png)
2014-10-06 06:12 UTC, Ryan Kaldari
Details

Description Alexander Karnstedt 2008-11-17 11:47:00 UTC
Recently I noticed that most of the fonts in SVG images are messy. I assume it's related to the recent replacement of the renderer software.

Examples:
* http://de.wikipedia.org/wiki/Bild:Jade-weser-muendung_map_de.svg
* Map of the bay bridges in http://en.wikipedia.org/wiki/San_Mateo–Hayward_Bridge

.. these SVG's looked good a few weeks ago.
Comment 1 Brion Vibber 2009-08-03 16:53:52 UTC
Assigning SVG bugs to Ariel -- need a cleanup pass to see what's fixed up by a librsvg upgrade, what can be resolved with fixes to our font configuration, what can be fixed on our end, and what still needs to be pushed upstream.
Comment 2 Matthias Mailänder 2009-09-16 14:31:20 UTC
Especially chemical formulas are affected by the bad font rendering. When saving chemical formulas as text without text converted to path, there are severe rendering issues, especially when using scaled down versions. The font is sometimes too big, other times too small, but usually pixelish.

http://commons.wikimedia.org/wiki/Commons:Graphics_village_pump#bad_font_rendering_in_chemical_SVGs
Comment 3 Guillaume Paumier 2009-12-31 18:53:35 UTC
I assume this was fixed in the meantime; the example images look good now.
Comment 4 Alexander Karnstedt 2010-01-01 15:08:50 UTC
(In reply to comment #3)
> I assume this was fixed in the meantime; the example images look good now.
> 

???? No, the problem still is the same. Please directly compare a SVG and a PNG of the same image side by side. Like:
http://commons.wikimedia.org/wiki/File:Jade-weser-muendung_map_de.svg
http://commons.wikimedia.org/wiki/File:Jade-weser-muendung_map_de.png

The labels in the SVG are pixelated (particularly when downscaled), single letters are placed not accurate (jumping up and down, left and right). By now, it is absolutely not possible to have maps as SVG at Commons - because the labels are too ugly and unreadable.

For me (as a map maker), SVG usage at Commons is dead. The results are way to far from satisfying (there are a lot of other problems as well with SVG). 
Comment 5 Guillaume Paumier 2010-01-04 17:54:01 UTC
Created attachment 6925 [details]
Comparison of rendering by User and by MediaWiki

PNG rendering of the SVG test case by MediaWiki, compared to the reference PNG provided in comment #4.

Could you please describe what's wrong?
Comment 6 Alexander Karnstedt 2010-01-04 19:08:50 UTC
> Could you please describe what's wrong?
> 

Spaces between letters are not equal. Letters are jumpimg up and down the baseline. eg look at "Jadebusen". At "Lang-Lütjensand" t and j interfere with each other. 

Hence labels look somewhat messy at downscaled images.

Please note, that it looked well at the time I've uploaded the SVG. So something must have changed in the meantime, what causes these effects.
Comment 7 Guillaume Paumier 2010-01-04 19:32:06 UTC
Thanks. There are indeed some minor offsets for renderings of this large SVG at small sizes.
Comment 8 Derk-Jan Hartman 2010-11-04 03:48:25 UTC
Then that is most likely an rsvg bug. there are dozens of it. :(
Comment 9 PRO 2011-07-08 14:16:29 UTC
Looks really ok v1.17
Comment 10 Bawolff (Brian Wolff) 2011-07-08 15:34:58 UTC
(In reply to comment #9)
> Looks really ok v1.17

v 1.17 where? On Wikimedia, on your own wiki? SVG rendering isn't handled by MediaWiki, so the version of mediawiki doesn't really have any affect. Its the version of the program mediawiki uses to turn svgs -> pngs that matters, which is independent of the version of mediawiki.
Comment 11 Ariel T. Glenn 2011-09-18 08:24:43 UTC
giving svg bugs back to the pool.
Comment 12 PRO 2011-09-24 16:52:18 UTC
(In reply to comment #10)
> (In reply to comment #9)
> > Looks really ok v1.17
> 
> v 1.17 where? On Wikimedia, on your own wiki? SVG rendering isn't handled by
> MediaWiki, so the version of mediawiki doesn't really have any affect. Its the
> version of the program mediawiki uses to turn svgs -> pngs that matters, which
> is independent of the version of mediawiki.

It sounds implausible, see also: Bug:31122
Comment 13 Bawolff (Brian Wolff) 2012-11-22 23:29:33 UTC
>It sounds implausible, see also: Bug:31122
As implausible as that sounds, I can ensure you the version number of the program _NOT_ used to turn svgs into pngs does not affect how well the svgs are converted.


+keyword testme.

Is this still an issue?
Comment 14 Ryan Kaldari 2014-10-06 06:12:20 UTC
Created attachment 16676 [details]
another SVG rendering comparison (Liberation Sans)
Comment 15 Ryan Kaldari 2014-10-06 06:21:42 UTC
Our SVG font rendering still sucks. Attached a comparison of an SVG using the Liberation Sans font, which I know we have on the scaler servers (https://gerrit.wikimedia.org/r/#/c/126249/) and which I also have installed locally. The image on the left is my local rendering and the image on the right is the Commons thumbnail (recently generated). The Commons rendering is so bad it doesn't even look like the same font. The kerning is totally random, the letters are running into each other and the words look vertically squished. If rsvg can't render fonts correctly, is there anything else we could use?

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