On Sun, 29 Apr 2007 07:30:42 +0200, Jasper Schalken <jasperschalken@xxxxxxxxx> wrote: > The bug report: http://bugzilla.gnome.org/show_bug.cgi?id=434279 > > On 29/04/07, Jasper Schalken <jasperschalken@xxxxxxxxx> wrote: >> > You could have a look at the matrix convolution filter code. (Be >> warned >> > there are some minor bugs concerning edge effects IIRC) but it will >> serve >> > as an introduction to the different ways of treating edge data. >> >> Is that "void convolve_region(...) {...}" in >> /gimp/trunk/app/paint-funcs/paint-funcs.c? >> >> It doesn't have many comments, so I'm not sure what its doing nor what >> a convolution matrix is. I thought it would be along the lines of "for >> each pixel in the region make it the average of all the pixels within >> a certain radius". However, that gives a box blur and it may be >> Gaussian instead. >> >> I think I will just put this in a bug report and let someone who knows >> have a look. :S >> > <title>500 Internal Server Error</title> Looks like bugzilla is still in bed ;) The filter I was refering to is in the following file: gimp/plug-ins/common/convmatrix.c The variable names should be explicit enough to make the code self documenting but if you dont know what convultion or convultion matrix is you may want to read up a bit. The implementation is not far from what you outlined above, so it's not as intimidating as it sounds. The lanczos interpolation that was recently added works in a similar way with a larger matrix (and suffers from a similar "one size fits all" border extrapolations). On a large images these border issues are generally not a worry, but on small graphics like web buttons and glyphs they can become very visible as you have noted. This is probably worth a bug report if there is not one already since it will need to be dealt with more thoroughly for gimp to fullfil it's aims to be a top end application. HTH. _______________________________________________ Gimp-developer mailing list Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
