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Bug 135212 - Lighten Only is messing up colors
Lighten Only is messing up colors
Status: RESOLVED FIXED
Product: GIMP
Classification: Other
Component: General
1.x
Other Windows
: Normal normal
: ---
Assigned To: GIMP Bugs
GIMP Bugs
Depends on:
Blocks:
 
 
Reported: 2004-02-23 16:50 UTC by Lucas Langa
Modified: 2004-06-23 06:30 UTC
See Also:
GNOME target: ---
GNOME version: ---


Description Lucas Langa 2004-02-23 16:50:10 UTC 
Having a black background, do: 1. New transparent layer; 2. Add noise; 3.
Desaturate noise; 4. Change noise layer attribute to "Lighten Only".

In GIMP 1.x the change is not visible as you got only black background
beneath. In GIMP 2.0pre2 suddenly strange colours appear as if the noise
layer wasn't desaturated. But when you save the file and open it with 1.x,
you got the right effect of normal, desaturated noise.
Moreover, with some more layers, you can achieve very weird effects: when
you have a non-transparent layer over the noise layer and you turn it
invisible, then the noise where the non-transparent layer was, is corrupted
another way (for instance all noise was yellowish or greenish, but the area
where another layer was is not redish).
When you save the file and restart The GIMP, the corruption effect will
look totally different (and that means it is definitely a bug).

What is it all about? 

Regards,
kSh
Comment 1 Sven Neumann 2004-02-23 17:13:54 UTC 
Could you check if the problem goes away if you start gimp with the
--disable-mmx command-line option ?
Comment 2 Sven Neumann 2004-02-23 17:15:50 UTC 
Sorry, the command-line option that I want you to try is of course
called --no-cpu-accel.
Comment 3 Sven Neumann 2004-02-23 17:17:57 UTC 
*** Bug 130802 has been marked as a duplicate of this bug. ***
Comment 4 Lucas Langa 2004-02-23 17:20:37 UTC 
Yes, disabling MMX makes the problem go away. But it is only a
workaround. Maybe my CPU specs will help you: I own an Intel Pentium 4
2.4GHz with Hyper-Threading ON (it acts as two CPUs in the OS).
Comment 5 Sven Neumann 2004-02-23 17:21:13 UTC 
Sorry for marking this as duplicate. I accidentally entered the number
into the wrong entry.

I'd like to add that I cannot reproduce the problem on Linux using the
latest CVS version. Would also be nice if the bug reporter could
update since 2.0pre2 is not the latest released version.
Comment 6 Michael Schumacher 2004-02-25 11:10:20 UTC 
I can't reproduce this with current CVs on Win32, either.
Comment 7 Lucas Langa 2004-02-25 11:30:39 UTC 
Maybe it is HyperThreading specific?
I am just a user, not a programmer. I'd want to help you using the
latest snapshots but I have no compiling knowledge to make myself a
working copy from the sources. Is there a place where I can find some
guide on compiling The GIMP under Windows?
Comment 9 Michael Schumacher 2004-06-21 13:55:32 UTC 
Is this still present in GIMP 2.0.2 as distributed with the current installer?
Comment 10 Lucas Langa 2004-06-23 06:29:23 UTC 
Fortunately the problem went away. Hail the devs :)