GIMP Users - GMIC - A Powerful "Plugin"

[David]

One of the positive aspects of open source software, such as The Gimp, is that programmers love to develop new and/or improved plugins for it. Such is the case with G'MIC developed at a French systems laboratory, GreyC, in Caen, France, by David Tschumperlé and his co-workers. Although billed as a plugin, G'MIC is, in fact, an operating system that runs from within the Gimp. The site, http://gmic.sourceforge.net/ describes it thus:

"G'MIC is a script language for image processing, which comes with its open-source interpreter. It can be used to define complex image processing pipelines for converting, manipulating, filtering and visualizing generic 1D/2D/3D multi-spectral image datasets. By the way, it can handle color images, but also more complex data as image sequences or 3D volumetric data."

Given that description perhaps it's not surprising that people might be put off using what turns out to be an extremely powerful piece of kit. At the surface level it contains, apparently, 147 different filters some of which are familiar to most of us, but many, e.g. shock filters, isophotes, and anisotropic smoothing, are probably not so well known. At a deeper level you can use a command line prompt to test and develop your own ideas. The scripting language is said to be easy, but the documentation suggests otherwise.

I am slowly working my way through G'MIC testing some of the filters and if there is interest I shall post on what I find. At this point, I'll draw attention to several extra blending modes, not presently available in the GIMP itself, nor in PSP. They may be available in Photoshop, but I wouldn't know as I am not rich enough to be able to afford a copy.

Blending modes are to be found in the Layers section of the main menu in G'MIC. Apart from standard modes such as Multiply, Dodge and so on, there are more complex modes called Reflect, Stamp, Freeze, Interpolation, Negation and XOR, the last being a logical operator. A description of what all these other modes do and the maths behind them can be found at http://www.pegtop.net/delphi/articles/blendmodes/

Of the ones that I have looked at, the Interpolation mode looks interesting, particularly for sharpening and contrast. Another, Negation, is fun to play with.

Under the same Layers menu, there is a "Layers morphing" mode whereby you can, apparently, blend one image into another creating and storing all the morphs en route (that last phrase is French just in case David T reads this!)

The complete package can be downloaded from the address above, or via the plugins registry on the Gimp site. The zip file should be unpacked to the plugins directory in the Gimp folder. The documents state that all should be well if all files are put in the plugins folder, but I had to copy the dll files to the bin folder before I could get the system to work. Once the Gimp is running you should find G'MIC under the filter drop down menu, at the very bottom in its own section.

I would imagine that few photographers would be sufficiently interested or have enough time to work through this complex system, and that most of what is on offer may not be really useful, but there are probably some gems to be found (isophotes looks promising) that may have a wider appeal. Thus, if anyone else out there is interested, please let me have some feedback.

Cheers

David

[wjh31]

Its always interesting to hear about more powerful wats to get more from your photos, let us know if you find any gems! i may even have a play myself on your recomendation

[Donald]

David

Is this something else other than release of 2.7 which was reviewed by Rolf Steiner on his blog last week. In other words, are you talking about something that can be put into v2.6?

And, whether the answer be yes or no, I'd welcome any comment views you might post up.

Donald

[David]

Donald - Have you an url for Rolf Steiner? I can't seem to find any relevant link via Google. However, G'MIC is a separate entity in that it has been developed independently of the main Gimp team (I think). I first came across it 6 months ago, but didn't have time to look at it closely. The version to which I refer is an upgraded version and was posted a few days ago. I am running it on Gimp 2.6.7, but it should run on any recent stable version. I'm off to Scotland for few days, but will continue this thread when I return.

Cheers

David

[Donald]

Have you an url for Rolf Steiner?

My apologies to him and to you. His surname is Steinhort (which I knew, don't know why I got it wrong). The site is http://meetthegimp.org/.
Once I can breath properly, having torn muscle tissue somewhere inside and feeling very sorry for myself (nobody else does!), I'll be trying to get G'MIC into my version of 2.6.7.
Thanks again for the info.
Donald

[Colin Southern]

Once I can breath properly, having torn muscle tissue somewhere inside

Ouch - how did you manage to do that?

[David]

Thanks Donald - I don't think G'MIC is covered in that post. Sorry to hear about torn muscle, but I'm not surprised you don't get any sympathy. It's the same with me. Wives and others simply do not understand how much we men suffer!!!!

Hope your better soon.

Cheers

David

[Donald]

Ouch - how did you manage to do that?

I think it's because us athletic types have such highly tuned bodies ....... or us overweight, lazy types are out of condition (I'll leave you to choose).

Anyway, the high-powered anti-inflammatory drings obtained from the doctor this morning are kicking in .... and I just got an e-mail to say that the 70-200 L f4 IS has been despatched and is on its way. So, life's not so bad.

[willgoss]

G'mic is available at..... http://gmic.sourceforge.net/gimp.shtml

It will work with 2.7(not stable) or 2.6.7 but not 2.6.6 (troublesome release)

All the files should be copied into the Plugins File pointed to under Preferences....

I especially like the Color-Black & White for conversions....has Grain, Gamma, Brightness, Contrast and all the Colors as in Channel mixer.....newly added is Localized Contrast......

Another Winner is C2G part of the GEGL set......Use for Blends.....

[Donald]

My goodness, this looks amazing! Managed to get it in okay.

Definitely welcome any comments that fellow users have about things people find useful. Willgoss, thanks for the pointer to the Color - Black & White. That looks pretty impressive. I'll post up anything that I discover that I think you might be interested in.

[Donald]

Okay - First 'daft laddie' question.

What should the settings be in the Input/Output drop downs at the bottom left?

I've got an '.xcf' open in the GIMP. It has lots of layers. Then open GMIC and go to layers. And everyone I click on tells me, in the main window - "NOTE: This filter needs two layers to work properly. Set the Filter Input option to handle multiple layers."

Without revealing how stupid I am .... HELP!

[willgoss]

Not sure I can help much.....but...

On opening G'MIC I first added a Shortcut (Ctrl-G) since i open it so much......second I added the toolbox option for Gegl access......On opening G'MIC expand the G'MIC window to get the largest image possible.....

When using one of the filters it will be applied to the top layer unless, as I do, you set the outlet mode to add new layer, after Apply, you remain in the G'MIC and can add another effect to your new top layer again as another new top layer....

This is the only thing I set and use....I realize you can also set the fop layer to a mode in G'MIC but I have not explored this.....

[willgoss]

Another Filter.....Artistic-Cartoon---Overlayed at 50% Opacity.......

[David]

As Captain Oates is reported to have said "Coeee - I'm back!!!" I've been cut off for about 10 days by a decorator who cut through two computer connections to the internet but did not bother to tell me. Considerable problems with my provider have ensued until the slashed cables were found. Anyway, it looks as if GMIC has aroused some interest and I shall post further when I've caught up with the backlog of email.

David

[Donald]

Aahh, don't you just love getting redecorating work done!

[David]

Hi All - Donald raised a point about Input/Output options. Here are some notes that I have compiled about them. There are some interesting features.

Notes Regarding Input/Output in G'MIC

First, note that the size of the GMIC display window can be increased by dragging a corner with the mouse (left button). Working with a more or less full screen version of GMIC is useful.

Second, for the purposes of most of these notes, take an image and duplicate it times 2, giving a total of three layers.

Now take a straight forward filter such as – Artistic > Soft Glow, with amplitude set to 3.00 (so that you can easily see what's happening).

Before doing anything else, go to the Input / Output box (lower left corner) and click the drop down menu for the third box, labelled Output Preview. Now click All Outputs. If any transformation that involves more than one layer is carried out, then the preview image box will now show the results on all the affected layers as side-by-side images. Alternatively, you can see the effect on the 1st, 2nd, 3rd (or 4th layer if you have such) or on 1st and 2nd , 1st to 3rd , or 1st to 4th layers by activating the appropriate option. These notes use the All Outputs option.


Set the Input of Input / Output Box to:

Active (default) - the filter when applied to the active layer, say the top layer, will affect only that layer (the preview box will show only one layer). However, if you change the active layer using the GIMP layers box, GMIC does not recognise this change. Active means active as first encountered by GMIC.

Active and below - the filter affects both the top layer (active) and the one immediately below (the preview box will show the effects on the two layers, side by side).

All - the filter affects all layers, irrespective of which is active (the preview box shows all three layers).

Active and above - the filter behaves as now suggested, only on the active layer and the one above (if there is one).

All Visibles - the filter acts on only those layers that are visible.

All Invisibles - the filter acts on those layers that are not visible.

All Visibles (decr), All Invisibles (decr) and All (decr)- These had me fooled for a bit. They reverse the order of the layers in the Preview display and, see below, the order of newly created layers when the filter is applied.

Note that all the transformations that are being carried out here are on preview. There has been no need to actually apply them to the image up until now.

Set Output Mode to New layers and the Input option to All. Now Apply the filter. If All Outputs is still selected, then you should see six images side-by-side in the preview display and three new layers in the GIMP layers box. The filter creates the appropriate number of new layers according to the input instruction. The order in which the new layers are created depends on whether you use the (decr) option or not.

Setting the Output Mode to New Image and applying the filter creates, as expected, a new image, the nature of which has been determined by the Input instruction in GMIC.

GMIC does not appear to recognise alpha channels. Thus, if a mask has been applied to a layer, then GMIC will only affect the red, blue and green channels and simply removes any alpha layer. Another way of putting this is to say that GMIC does not recognise transparency.


Blending filters, found under the Layers Option, require (at least) two layers to work. Thus, the default Input option of Active Layer needs to be changed to Active and Below, or Active and Above. Again, the Preview window should show changes to the image before you decide to Apply the filter. Note the interesting feature that you can blend a layer with the one above it.

If you select the All or All Visibles inputs with a blending mode then the results are not intuitive. Blending does not occur between all layers, but between pairs of layers starting from the lowest two and moving up to the next two and so on. If there is an odd number of layers, the topmost layer remains unaffected, even if this is the active layer. To experiment with this create an image with at least five layers, all somewhat different. Pick a blend mode such as Screen so that the results of blending are obvious and reasonably predictable. Try the All Visibles and see what happens.

I hope these are useful. Comments are welcome as usual.

Cheers

David

[Donald]

David

Right, that's homework for the next few days sorted out.

Thank you for taking the time to set all this down in writing. I want to understand just what GMIC is about. Don't know yet how and when (or if?) I'll use it, but I want to know what my options are and what they do.

As Colin has often written about 'the other one', it's not that you have to use every tool every time, but it's nice to know and understand what's in the toolbox.

[Davey]

gmic completely slipped me by and I'd not heard of it until now although looking at the releases it's been around for over a year. I will definately be taking a look at it though and recommending to several friends who use gimp and will find it useful and/or interesting. Thanks.

[willgoss]

Of interest the latest G'MIC version http://gmic.sourceforge.net/gimp.shtml is out today.....

He writes.....


Ronounours says:

Dear all,

I'm happy to announce the release of the 1.3.2.8 binary update of the G'MIC plug-in for GIMP. There is actually only minor 'visible' improvements compared to previous versions, mainly bug corrections and improvements of the internal engine.

If you don"t know what G'MIC is : This is an "all-purpose" plug-in proposing a set of various image filters and effects. Could be see as a mix between 'FX-foundry' and 'Mathmap' (each filter is written in a dedicated language for image processing).

This version will define the basis for a student project I've proposed which intend to define lot of new different filters (should be available through the internet update mechanism of G'MIC, then). So, this 1.3.2.8 package is probably the latest one of this year.

So, do not hesitate to test and report bugs or new ides/whishes.

[David]

Hi Will - I've downloaded this new version, installed it, but when I call it up in Gimp I get the header stating version 1.3.2.5 not 1.3.2.8. Does your version give "5" or "8" at the end?

Cheers

David