Problems with the Inkblot filter

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Uktrunie
Posts: 154
Joined: Sun Jul 18, 2010 4:48 am

Problems with the Inkblot filter

Postby Uktrunie » Fri Oct 01, 2010 12:45 pm

Hi people,

Needing some help here...

I'm using the Inkblot filter that you can find in the Textures submenu... but I'm getting this "noise" or something. Take a look at this image.

Image

Note the little dots around the yellow shape.

It's not happening with the blue one, and they both are using the same filter. So I suppose it has something to do with the parameters of the filter that combined with the yellow produces those pixels... But can't find what.

Any ideas I can try?

BTW, the parameters on that filter are almost identical to the defaults (only gaussian blur is a little higher).

Thanks for you time and help.
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ivan louette
Posts: 215
Joined: Thu Aug 21, 2008 4:08 am
Location: Belgium

Re: Problems with the Inkblot filter

Postby ivan louette » Sat Oct 02, 2010 5:41 am

I cannot reproduce your problem here with Inkscape 0.48 and 0.48 devel.

Do you use an older version ?

ivan
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~suv
Posts: 2272
Joined: Sun May 10, 2009 2:07 am

Re: Problems with the Inkblot filter

Postby ~suv » Sat Oct 02, 2010 9:15 am

ivan louette wrote:I cannot reproduce your problem here with Inkscape 0.48 and 0.48 devel.

Reproduced with Inkscape 0.47, 0.48 and 0.48+devel (on OS X 10.5.8): the yellow gradient appears to show erroneous dark pixels if it has transparency and some (minimal) amounts of red and green (RGB). The effect (random dark pixels at the edges) does not happen if the inkblot filter is used on an object with a 'pure' yellow gradient.

filter-inkblot-048-2-path4687.png
bitmap export (partially white bg)
filter-inkblot-048-2-path4687.png (27.05 KiB) Viewed 2200 times

filter-inkblot-048-3-path4687-screenshot.png
Screenshot from 0.48+devel
filter-inkblot-048-3-path4687-screenshot.png (62.31 KiB) Viewed 2200 times

filter-inkblot-048-3.svg
SVG file used to reproduce
(209.31 KiB) Downloaded 183 times
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ivan louette
Posts: 215
Joined: Thu Aug 21, 2008 4:08 am
Location: Belgium

Re: Problems with the Inkblot filter

Postby ivan louette » Sat Oct 02, 2010 8:01 pm

Yes I saw it and I corrected it. It was due to the negative value (-0,25) in the Composite at the end. It only occurs when a gradient is applied to the shape.

However I tried different changes to this filter and I propose the attached one which is even simpler than the original. I will commit the change together with next filters revision.

Thanks to find it !

ivan
Attachments
filter-inkblot-048-4.svg
(186.32 KiB) Downloaded 206 times
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~suv
Posts: 2272
Joined: Sun May 10, 2009 2:07 am

Re: Problems with the Inkblot filter

Postby ~suv » Sat Oct 02, 2010 8:31 pm

ivan louette wrote:However I tried different changes to this filter and I propose the attached one which is even simpler than the original. I will commit the change together with next filters revision.

Looks fine to me (tested with my previously attached file) - even after cleaning the monitor I can't spot any dark blots at the edges of the filtered objects ;)


@Uktrunie - just copy the file Ivan attached into the 'filters' directory inside your Inkscape preferences directory ('~/.config/inkscape/filters' on linux/osx, '%APPDATA%\Inkscape\filters' on Windows) and the revised Inkblot filter will be added in the filters menu ('Filters > Textures > Inkblot -REV-').
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ivan louette
Posts: 215
Joined: Thu Aug 21, 2008 4:08 am
Location: Belgium

Re: Problems with the Inkblot filter

Postby ivan louette » Sat Oct 02, 2010 9:17 pm

~suv wrote:Looks fine to me (tested with my previously attached file) - even after cleaning the monitor I can't spot any dark blots at the edges of the filtered objects ;)


Did you see some blots remaining after shutting down the monitor with the previous filter version ? ;)
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Uktrunie
Posts: 154
Joined: Sun Jul 18, 2010 4:48 am

Re: Problems with the Inkblot filter

Postby Uktrunie » Sun Oct 03, 2010 1:28 am

I'm sorry guys. My father is very ill. I won't be using a computer for quite a long, at least, not my computer. But I'll check all this when I have the time.

Thankyou very much for your time and help.
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ivan louette
Posts: 215
Joined: Thu Aug 21, 2008 4:08 am
Location: Belgium

Re: Problems with the Inkblot filter

Postby ivan louette » Sun Oct 03, 2010 5:02 am

Don't bother and best wishes for your father.

ivan
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Uktrunie
Posts: 154
Joined: Sun Jul 18, 2010 4:48 am

Re: Problems with the Inkblot filter

Postby Uktrunie » Fri Oct 08, 2010 12:51 pm

Thanks ivan. It worked like a charm!
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