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Bug 725359 - only build and attach RGB color profiles to PNGs when both gAMA and cHRM are present
only build and attach RGB color profiles to PNGs when both gAMA and cHRM are ...
Status: RESOLVED FIXED
Product: eog
Classification: Core
Component: image viewer
unspecified
Other Linux
: Normal minor
: ---
Assigned To: EOG Maintainers
EOG Maintainers
Depends on:
Blocks:
 
 
Reported: 2014-02-28 00:07 UTC by pdknsk
Modified: 2019-05-03 14:03 UTC
See Also:
GNOME target: ---
GNOME version: ---


Attachments
chrm.patch (1.50 KB, patch)
2014-02-28 00:07 UTC, pdknsk
none Details | Review

Description pdknsk 2014-02-28 00:07:49 UTC
Created attachment 270522 [details] [review]
chrm.patch

eog builds an RGB profile from cHRM (when both iCCP and sRGB are missing), and assumes gamma of 2.2 when gAMA is missing. This yields poor results when the PNG was made on a Mac. The PNG specs mention, albeit not categorically, that both gAMA and cHRM should be used to color correct an image.

It's more likely that such an image had a (stripped) sRGB profile or chunk. And thus rather than trying to build a profile from only half the necessary information, eog should not.

For full effect, this patch should also be applied.

https://bugzilla.gnome.org/show_bug.cgi?id=554498#c7
Comment 1 Felix Riemann 2019-05-03 14:03:53 UTC
commit 78c0153ef904a3664b31387ddbf076a705b67d09
Author: pdknsk <>
Date:   Fri May 3 15:40:45 2019 +0200

    EogMetadataReaderPNG: Only build profile from cHRM if gAMA is present
    
    It's more likely that such an image had a (stripped) sRGB profile or chunk.
    And thus rather than trying to build a profile from only half the necessary
    information, eog should not.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=725359
---
This problem has been fixed in our software repository. The fix will go into the next software release. Once that release is available, you may want to check for a software upgrade provided by your Linux distribution.