On Wed, 07 Mar 2007 08:53:34 +0100, Sven Neumann <[EMAIL PROTECTED]> wrote:

>> 3) Ok, this is the serious one: The whole blurred region is shifted 1
>> pixel down. To check this, create a new white image with a single
>> black pixel in the middle, and blur it with radius=1. Go back and
>> forth and you will see the 3x3 gray square shifting down.
> Again, how is that a problem? This example code is meant to illustrate
> some concepts of GIMP plug-in development, in particular how to add a
> preview to your plug-in window. It is not meant to perform any useful
> image manipulation.

How is it a problem that there are these small and varying offsets all the  
way through gimp?

I suspect this is not so much a bug in the example code, which as you say  
is just an example, but in gimp itself.

I have already submitted bugs comments indicatiing significant drift in  
scaling with NONE interpolation, there is residual drift in lanczos that I  
dont believe comes from the scaling code , there are fiddle factors to  
correct offsets in a number of areas.

Rather than dismissing this report, it may serve as a useful means of  
triangulating to find the root cause of some of these drifts.

If scaling, rotation and now plugins show drift it should help eliminate  
the superficial code and enable tracking this back to the problems in the  

This is only gut feeling on my part but it seems that the evidence is  
mount to confirm what I suggested six mounths ago when I first started  
looking at lanczos.

Thanks to Luis for taking the time to notify the apparent error.

Gimp-developer mailing list

Reply via email to