Color Masks in Gimp

Using the latest gimp AppImage from 2017-08-07 and the latest McGimp release on os x 10.11, using the Foreground Extraction tool, I can’t change the “Engine” combo box because it is grayed out. @patdavid @Carmelo_DrRaw @partha – any ideas?

@s7habo how on earth did you do that, could you record a video? I tried in 2.9.6, and like @paperdigits wrote I cannot select the engine, it’s grayed-out, and using whatever engine is active the result is and always has been garbage.

Yes, this is sometimes the problem with blurred or noisy parts of the image. The trick is first, to separate the foreground from the background as precisely as possible using brushes before applying the algorithm.
If the first result is not satisfactory, you can make further corrections with the brush by switching between foreground and background selection option of the brush.

What I don’t like about implementation in GIMP is that after the initial implementation of the algorithm after each additional stroke of the brush, the calculation is starting to run again! In this way, this already very slow process is unnecessarily stretched even longer.

In some cases helps “Feather Selection” option in brush menu.

If the foreground selection is done and there are still artifacts, I copy the selection to the new layer and make manual corrections with the help of eraser tool with low hardness and opacity switching between “erase” and “un-erase” mode of the tool.

I’m using Gimp from ppa:otto-kesselgulasch/gimp-edge and ATM I have GIMP 2.9.7.

Machine_selector

Strange, but until now, I’ve always had this option! I’ll make a video later and put it here.

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It is grayed out for me as well, I’m on @partha’s version (2.9.5 I think)

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You need to build gegl with libumfpack so that gegl:matting-levin gets build.

Edit: On Debian you need libsuitesparse-dev for that.

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@Morgan_Hardwood Here’s the video:

Please note: I have scaled the original image for the faster calculation speed of the engine for Video and shortened the waiting times of the calculation. Original video length was about 6 min.

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I’ll try to implement this in the appimage, and make a new package.

Thanks for the hint!

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I know the question has been answered for getting the matting extraction (ty @houz).

For using it, I had recorded a video a few years ago that used this as part of an experimental fork of GIMP back then:

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For me the ‘Levin-Matting’ algorithm crashes gimp. I have to try gimp 2.9.7 if there isn’t this crash.

@s7habo
Thank you for your great video!

??? I don’t know what any of that means. I am trying to change the engine, but it grayed out.

If the engine is grayed out, your version of gimp isn’t built with support for that option.

What versions are supported? I have the most recent developerer version.

Can’t change to levin-matting in 2.9 It’s grayed out

I have the exact same issue.

For anyone on Windows, samj’s portable compile works with both matting options.

I pinged the GIMP dev who is making the official installer. I’ll report back once I know more. I suppose that it’s just an oversight.

Edit: The answer was that it was just forgotten indeed. The next release will have it fixed.

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Thanks to everyone that helped me! I really apprecite it!

Hi,
I’m using the flatpak for GIMP 2.10.6 and the Matte Engine drop-down menu is grayed out. Could it be that the flatpak is missing a library ?

Most likely the flatpak is missing that library. If you’re enterprising, diff the version from gimp’s repo with the version from the flathub repo. They were supposedly the same… If they’re still the same, file a bug with the gimp project. If they’re different, the issue is probably with flathub’s version

GEGL needs to be compiled with umfpack support for matting-levin to work.