Page MenuHomePhabricator
Create Task
Maniphest T107706

inconsistent contrast for PNG thumbnail creation
Closed, DuplicatePublic
Actions

Description

"Recently" something changed in the PNG thumbnailing pipe. Lets just pick this file: https://commons.wikimedia.org/wiki/File:J%C3%BCrgen_Alberts_-_pv_portrait_02-3.png and purge only the thumbnail of the current version:

Screenshot from 2015-08-02 20-19-27.png (323×1 px, 87 KB)

Even though, the current version and the first version are the same file, the thumbnail differs significantly.

Related Objects

Event Timeline

McZusatz created this task.Aug 2 2015, 6:27 PM
McZusatz raised the priority of this task from to Needs Triage.
McZusatz updated the task description. (Show Details)
McZusatz added subscribers: McZusatz, • brooke, Bawolff, Perhelion.
Restricted Application added a subscriber: Aklapper. · View Herald TranscriptAug 2 2015, 6:27 PM
McZusatz added a project: MediaWiki-File-management.Aug 2 2015, 6:28 PM
Restricted Application added a project: Multimedia. · View Herald TranscriptAug 2 2015, 6:28 PM
Aklapper added a comment.Aug 3 2015, 8:55 AM

I'm not sure this is "inconsistent" but rather a change in behavior. :)
Histogram comparison:

T107706.png (242×414 px, 8 KB)

Only recent thumbnail related stuff I'm aware of is T102870: Reduce amount of thumbnail buckets, as https://phabricator.wikimedia.org/T77697 is still under discussion.

Restricted Application added a subscriber: Matanya. · View Herald TranscriptAug 3 2015, 8:55 AM
McZusatz added a comment.Aug 3 2015, 9:44 AM

Indeed, the last change to https://github.com/wikimedia/mediawiki/blame/9c8f333eb87f128933dd754f4c7e4b26fa1cf514/includes/media/Bitmap.php#L160 was Jan 2014.

Did anyone update the binaries for imagemagick's convert? And what version is running right now?

• Gilles closed this task as a duplicate of T106516: Greyscale pngs without gAMA chunk rendered with incorrect contrast [or setting the gamma in GIMP exports to PNG].Aug 5 2015, 8:04 AM
Restricted Application added a subscriber: Steinsplitter. · View Herald TranscriptAug 5 2015, 8:04 AM
Yann subscribed.Dec 29 2015, 5:40 PM

Again here: https://commons.wikimedia.org/wiki/File:1908_Rover_20hp_front_suspension_design.png

Restricted Application added a project: Commons. · View Herald TranscriptDec 29 2015, 5:40 PM
Restricted Application added a subscriber: StudiesWorld. · View Herald Transcript
Content licensed under Creative Commons Attribution-ShareAlike (CC BY-SA) 4.0 unless otherwise noted; code licensed under GNU General Public License (GPL) 2.0 or later and other open source licenses. By using this site, you agree to the Terms of Use, Privacy Policy, and Code of Conduct. · Wikimedia Foundation · Privacy Policy · Code of Conduct · Terms of Use · Disclaimer · CC-BY-SA · GPL · Credits