just did a simple test * 16x16 rgb image * select half (vertically in my case) and fill in * run the Gaussian blur, 1 blur pixel * Hold Ctrl+F to rerun the filter many times - Image will eventually turn black - Happens for RLE and IIR If its a rounding error, you could see if theres some way to give a more accurate result (cast to float?) - you probably alredy do that.. At worst, you could dither so every second pixel rounds up. gg@xxxxxxxxxxx wrote: > On Tue, 24 Apr 2007 20:57:43 +0200, Sven Neumann <sven@xxxxxxxx> wrote: > >> Hi, >> >> On Wed, 2007-04-25 at 02:41 +1000, Jasper Schalken wrote: >>> This is what I thought was a bug (I posted >>> herehttp://bugzilla.gnome.org/show_bug.cgi?id=432978) but Sven Neumann >>> says I should discuss it on here first. >> Your video shows the blur tool being used on large areas of black color >> and small areas of white color. The average of this is a dark gray. Now >> when you continue to blur, you are mixing a dark gray with black. If you >> go further, you end up with all black. >> >> But there could very well be rounding errors in the blur tool code. >> There are even most definitely rounding errors as we are only working >> with 8bit per channel and rounding errors are unavoidable then. But >> please take a look at the code and see if there's anything we could >> change to improve this. >> >> >> Sven > > Jasper , your bug says: > >>> It's algorithm >>> appears to favour dark colours when they are included in the blur. > > Why do you say that? Does it still favour dark colours if the image is > predominantly white? > >>> From my understanding, the average lightness of a given image should >>> always >>> remain constant as it is blurred. > > What is your understanding , of what blur tool? > Is there some specific blur algorithm that you believe does preserve > lightness or is this just an assumption you were making? > > Maybe you could be more precise about what blur you are refering to , > there are several IIRC. > > Please try to be a little more specific about what you are reporting. > > Thanks. > _______________________________________________ > Gimp-developer mailing list > Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx > https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer > -- See MetaVR Visuals Used at the Combat Studies Institute http://www.metavr.com/casestudies/baghdadviews.html Campbell J Barton 133 Hope Street Geelong West, Victoria 3218 Australia URL: http://www.metavr.com e-mail: cbarton@xxxxxxxxxx phone: AU (03) 5229 0241 _______________________________________________ Gimp-developer mailing list Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
