[Digikam-devel] Bugs observed, was Re: [patch SVN 0.9.0] imageeffect_noisereduction.cpp

[Peter Heckert]

Gilles Caulier wrote:
> On Thursday 27 April 2006 10:07 pm, Peter Heckert wrote:
>   
>> I have reverted all my modifications and it still crashs. (segmentation
>> fault)
>> Currently I am unable to track this down.
>>
>> Is it possible, that crash comes from floating point errors, such as
>> calling pow(-1,x)?
>>     
>
> I remember a bug into your code when i have backport your implemention in 
> digiKam plugins. The probelm is a divide by 0 somewhere.
>
> You have changed :
>
> m_lookaheadInput->setRange(0.5, 10.0, 0.5, true);
>
> to 
>
> m_lookaheadInput->setRange(0.0, 20.0, 0.01, true);
>
>   
I changed this to zero, because this makes sense with the new filter 
code, which
accepts arbitrary float values for "lookahead". I hope I can send the 
improved filter code soon.

This shouldnt cause crashing. Division by zero  doesnt cause crash, it 
causes odd results. (This depends on compiler options)
log(0) or sqrt(-1) causes exceptions, so far I know.
NaN values (Not a Number, uninitilized float variables) cause crashes. 
Therefore I set all buffers to zero before I use them.

> Check this point...
>
> If you want a backtrace after a crash, run digikam into gdb...
>   
Until now I got the message, that backtrace is of little value. Today I 
had more luck.
(Backtrace appended)
Steps to reproduce:
Open image. Size doesnt matter. Open noisereduction. Open 2nd tab. Move 
"Color" rubber a little bit to left direction.
If it doesnt crash, move it a little bit more to left.
Reproducibility: 100%

Also I still have another bug:
Steps to reproduce:
Open image. Size doesnt matter. Open noisereduction. Open 2nd tab. Move  
"Luminance" rubber a little bit.
Remove mouse, wait until preview is filtered. Put mouse again over the 
rubber.
Effect happening: The rubber is  still connected to moue movement, it 
has focus without mouse button pressed.
Effect expected:  You know ;-)
Reproducibility: 30%
 
Another bug:
Progress bar is very narrow. It is only 2-3 mm long on my screen.

I have this problems, since userinterface got the new look. (I liked the 
old look more and had no problems with it;-)
Yesterday I downloaded a completely fresh copy from SVN, this didnt cure 
the problems.

Would be helpful to know, if other people observe the same effects.
I have made a completely fresh user account; when I invoke digikam from 
there, then I get the same effects.
So it shouldnt depend on user preferences.

Possibly it depends on compilation. My compiler is:

gcc (GCC) 4.1.0 20060304 (Red Hat 4.1.0-3)
g++ (GCC) 4.1.0 20060304 (Red Hat 4.1.0-3)

> VERY IMPORTANT : If you change something into option description, please 
> change it too into plugin handbook :
>   
Will do this. That means, I dont change another thing in near future, 
default settings excepted ;-)

greetings,

Peter

-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: backtrace.txt
URL: <http://mail.kde.org/pipermail/digikam-devel/attachments/20060428/4017048b/attachment.txt>