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Bug 105577 - gimp_bilinear_rgba () incorrect alpha handling
gimp_bilinear_rgba () incorrect alpha handling
Status: RESOLVED FIXED
Product: GIMP
Classification: Other
Component: libgimp
git master
Other All
: Normal normal
: 2.0
Assigned To: GIMP Bugs
Daniel Egger
Depends on:
Blocks: 72876 105496
 
 
Reported: 2003-02-08 12:56 UTC by Yeti
Modified: 2004-12-22 21:47 UTC
See Also:
GNOME target: ---
GNOME version: ---

Attachments
Proposed patch (1.61 KB, patch)
2003-02-08 12:57 UTC, Yeti 		none Details | Review

Description Yeti 2003-02-08 12:56:58 UTC 
The gimp_bilinear_rgba () function (libgimpcolor/gimpbilinear.c)
handles alpha channel as if Gimp used premultiplied alpha.
But all Gimp core and almost all plugins use separated alpha.

I'm attaching a patch against CVS HEAD changing alpha handling from
premultiplied to separated.

This patch itself seems to fix alpha problems in two plug-ins using
gimp_bilinear_rgba (): bug #72876 and bug #105796.
Comment 1 Yeti 2003-02-08 12:57:54 UTC 
Created attachment 14203 [details] [review]
Proposed patch
Comment 2 Yeti 2003-02-08 12:59:47 UTC 
I'm sorry, the second plug-in is bug #105496.
Comment 3 Sven Neumann 2003-02-09 00:50:56 UTC 
IIRc, these two plug-ins are the only one that use gimp_bilinear_rgba().
Comment 4 Sven Neumann 2003-04-17 12:18:58 UTC 
Um, I lost track of this stuff a little. Do I assume correctly that
the patch is still valid and should be applied?
Comment 5 Yeti 2003-04-17 12:25:27 UTC 
It's valid, but already applied, see changelog:

2003-02-18  Sven Neumann  <sven@gimp.org>

  Applied patches from David Necas <yeti@physics.muni.cz> that fix
  incorrect RGBA resampling in a number of plug-ins:

  * libgimpcolor/gimpbilinear.c (gimp_bilinear_rgba): fixes RGBA
  resampling in Map Object and Lighting Effects plug-ins (#72876 and
  #105496).

It probably only remains to be closed here in bugzilla.