Details
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Type:
Improvement
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Status:
Closed
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Priority:
Minor
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Resolution: Fixed
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Affects Version/s: 1.7.1, 1.8.12, 1.9.8, 2.0
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Component/s: Maths filters
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Labels:None
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Database:Any
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Affected Branches:MOODLE_17_STABLE, MOODLE_18_STABLE, MOODLE_19_STABLE, MOODLE_20_STABLE
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Fixed Branches:MOODLE_19_STABLE, MOODLE_20_STABLE
Description
Moodle renders Tex-images as GIF-files of rather low quality. Images of higher quality, like the png-version of wikipedia.org, would be nice.
Attachments
Issue Links
| This issue is duplicated by: | ||||
| MDL-19228 | [Patch] Use PNG as default image format for latex render |
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Activity
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My computer will not unzip that latest zip file 
So you have any idea what is wrong.
And, if you could submit it as a patch, that would be a bonus. Have you seen http://docs.moodle.org/en/Development:How_to_create_a_patch?
So you have any idea what is wrong.
And, if you could submit it as a patch, that would be a bonus. Have you seen http://docs.moodle.org/en/Development:How_to_create_a_patch? Ok, here's a patch I have created before I've seen there's already a bug open for it, and code that I could have used to do it in 30' instead of nearly 2 hours of coding and testing 
The patch offers the admin the ability to choose the format (GIF and PNG) in case the user base is stuck using browsers that have still problems with certain PNG images (like first versions of IE 6.0 that had a lot of trouble with transparent PNGs). It also automatically 'downgrades' the output format to GIF if convert is not available but the admin selected PNG as the output format.
The patch is for 1.9.7+ (current as of today) and should be easy to forward port it to 2.0 if accepted (I'd do it).
Saludos,
Iñaki
The patch offers the admin the ability to choose the format (GIF and PNG) in case the user base is stuck using browsers that have still problems with certain PNG images (like first versions of IE 6.0 that had a lot of trouble with transparent PNGs). It also automatically 'downgrades' the output format to GIF if convert is not available but the admin selected PNG as the output format.
The patch is for 1.9.7+ (current as of today) and should be easy to forward port it to 2.0 if accepted (I'd do it).
Saludos,
Iñaki Iñaki,
the patch looks otherwise good but remember that 4th file - filter/tex/texed.php and lines 25 & 26
$image = md5($texexp) . ".gif";
$filetype = 'image/gif';
should also use $CFG->filter_tex_convertformat
( http://moodle.org/mod/forum/discuss.php?d=120418#p532389 )
( http://moodle.org/mod/forum/discuss.php?d=120418#p532389 ) Hi Mauno,
if fact they shouldn't , as that file always uses mimeTeX to render the images, so only GIFs will be created.
Saludos,
Iñaki.
, as that file always uses mimeTeX to render the images, so only GIFs will be created.
Saludos,
Iñaki. Hi,
here are updated patches for both 1.9.7+ and HEAD (current as of today). The patch does add a configurable filter setting that defaults to GIF. There are a couple of reasons for this:
- It's the safe default value for every single graphical browser going back to Mosaic (not that Mosaic supported transparent GIFs, but you get the idea
), and has been the default format in Moodle so far (so you get no surprises by default).
- On my test machine, 'convert' consistently creates smaller files for the same LaTeX expression when creating GIF files (sometimes noticeably smaller, even less than half the size of th PNG file). This is a real gain when you don't actually need PNG because your GIFs are the same quality of your PNGs (the ones I get on my test machine are identical quality wise).
To summarize, if you need PNGs, you can get them (provided you have LaTeX, dvips and convert installed and you configure the filter settings acdordingly), but if you don't need them or want to play on the safe side, you can still get your gool ole trusted GIFs
Saludos,
Iñaki.
- It's the safe default value for every single graphical browser going back to Mosaic (not that Mosaic supported transparent GIFs, but you get the idea ), and has been the default format in Moodle so far (so you get no surprises by default).
- On my test machine, 'convert' consistently creates smaller files for the same LaTeX expression when creating GIF files (sometimes noticeably smaller, even less than half the size of th PNG file). This is a real gain when you don't actually need PNG because your GIFs are the same quality of your PNGs (the ones I get on my test machine are identical quality wise).
Saludos,
Iñaki. Hi Dan,
filter_tex_convertformat can only be set by users with moodle/site:config permission in the system context (just like the rest of the TeX filter settings in the same page, which as far as I know are not cleaned either).
I'd say that anyone that gives that permission to non-trusted users has a big problem already . And I'd expect users with that permission to know what they'll get if they put '&& rm *' as part of the setting value
Saludos,
Iñaki.
. And I'd expect users with that permission to know what they'll get if they put '&& rm *' as part of the setting value
Saludos,
Iñaki. Looks perfect (while keeping current behavior for "mimetex" sites), isn't it?
+1 Great work Iñaki (and the rest!)
Ciao
Hi Iñaki,
No, not at all - very sorry to have not commited them already
cheers
Dan
cheers
Dan Fixed in CVS for both 1.9.x and HEAD.
Thanks a lot to Miro Goepel for the bug report and all the people that contributed suggestions and feedback
Saludos,
Iñaki.
Saludos,
Iñaki. 
component change