| VitaliyFilippov | |
| Aug 18 2010, 3:52 PM |
| F6575: Always-Resample-svn89562.diff | |
| Nov 21 2014, 11:01 PM |
Although code comments tell us "Initialise the destination image to transparent _instead_ of the default solid black, to support PNG and GIF transparency nicely", the black color is always taken as transparent when downsampling GIF images.
See the patch attached.
Version: 1.17.x
Severity: enhancement
| Status | Subtype | Assigned | Task | ||
|---|---|---|---|---|---|
| Open | None | T18456 GIF Issues (tracking) | |||
| Declined | None | T26855 Black color is always taken as transparent when downsampling GIF images using GD |
Fenyx4 wrote:
I was able to workaround this by changing $wgUseImageMagick to true in LocalSettings.
And then I just wiped out the images/thumbs directory and it redid all the gifs correctly.
*Bulk BZ Change: +Patch to open bugs with patches attached that are missing the keyword*
Still actual for svn89562. Any progress?
(In reply to comment #2)
I was able to workaround this by changing $wgUseImageMagick to true in
LocalSettings.
And then I just wiped out the images/thumbs directory and it redid all the gifs
correctly.
That's not very good to use external converter when there's standard PHP GD available.
Always resample setting + correct imagecolorallocatealpha
Additional comment: I think MW should have a setting for always downsampling paletted images with "imagecopyresampled" instead of "imagecopyresized" as the latter preserves transparency, but makes images ugly because of NearestNeighbor interpolation.
Attached:
sumanah wrote:
Comment on attachment 7636
includes/media/Bitmap.php.diff
Obsoleted by Vitaliy's next patch.
sumanah wrote:
Vitaliy, I am so sorry for the wait for a response. To get this reviewed faster, I'd love to get it moved into Gerrit, our code review system. https://www.mediawiki.org/wiki/Git/Tutorial gives you instructions on how to do that. If this issue is still reproducible, could you submit it that way?
Thank you for the patch.
Vitaliy, could you please address the concerns posted by Brian Wolff on that Gerrit changeset?
$wgGDAlwaysResample needs entry in DefaultSettings.php.
Also should justify why a global is needed (what circumstances would you want the behaviour overriden)
Anyone knows if this is still a problem? If it is, can you please provide clear steps to reproduce the problem and include MW and GD versions?
https://gerrit.wikimedia.org/r/#/c/mediawiki/core/+/22945/ for the records.
Unfortunately closing this Phabricator task as no further information has been provided.
After you have provided the information asked for and if this still happens, please set the status of this task back to "Open" via the Add Action... → Change Status dropdown. Thanks!