In Adobe Illustrator it's possible to apply gradient along a path or Gradient on Strokes.
Path-determined gradients were first introduced in CS2, if i'm not mistaken, and have been improving ever since.

In CS6 implementation of the feature yields some interesting results (this is an example of directional gradient along a path).


Some irregular gradients are presented in GIMP, Shaped gradients are very interesting to play around with, but none of them are close to ^.
This is still not possible to do in another vector graphics editor - Inkscape. (I don't know about CorelDRAW or Xara Designer - never tried them)
GIMP is a raster image editor with some vector graphics elements (paths).
The question for GC script writers and gimpologists: is it possible to write a script/plugin for GIMP that would do directional gradient along a path?
There is a script by RobA that can sample gradient along a path. Can the reverse be done: to tell GIMP to draw gradient along path within, say, a selection?

in way a closed path is a selection, right ?

Can you reproduce the last image in GIMP?
There should be a specified path for stroke/blend within a selection (selection could be a closed path as well, why not)

ah okay, i get it

i was under the impression there was a RobA script that lets you stroke a path with a gradient, but it seems i was wrong

there is a RobA script that fills a selection with a gradient (RMA path blend), but it does not what you are after

it seems there is the need for a new script

Esper, I should have been more explicit, sorry. Yes, it's a directional gradient along a path i'm after.

no you were pretty clear, it was me who was thinking wrong

there is the possibility to stroke a path with the airbrush tool and use a gradient, but im not very expereinced with this kind of stuff
see here:
viewtopic.php?f=23&t=1140#p12925

Thank you Esper!
I had no idea it was possible to paint with airbrush using gradient.


I had to do it in GIMP 2.6, because Airbrush tool options have changed in 2.8 and Mavin's screenshots are those of 2.6.
Besides, all I could get with 2.8 airbrush - was a FG color instead of gradient, must have something to do with my messed up
GPS brush dynamics, otherwise it's a bug.

It is pretty close to what I was seeking, although, I had to sweat a little bit adjusting a length in a/brush options to get predictable results.
the answer to my question in opening post is clear: it is possible to write a script. Thank you, Esper, again, for pointing me in the right direction!

Kit try clicking random colors in your dynamics as see if that helps to make paint with gradient. Just set the gradient you want to use and click that.

I was able to do something like the image below with Stroke Path and Brush Dynamics:

But it is really hard to achieve the second image that you have posted. The task is complicated in intersections when you have a selection.

what kind of brush dynamics did you use exactly, YAFU ?

I created a new brush dynamic. You see here how to:
viewtopic.php?f=23&t=5355
I checked the boxes size-fade and color-fade. And you need play with Fade Length value and Brush Spacing for the second image.

@molly - i've tried to randomize color, but with spacing set to 1 in brush editor it didn't work out quite well.

@YAFU - really nice job!!! Did you use brush dynamics to fading size or stroke within selection?
As for the 2nd AI image, maybe the complexity lies within raster image editor limitations, i'm actually surprised gradient versatility in Inkscape is
inferior to that of Adobe Illustrator.

Edit: OK, got it. Posted my answer before I saw your response to Esper's question

For the rainbow you can use the following technique:
http://www.gimpchat.com/viewtopic.php?f=8&t=3089

But only with the airbrush. With Paintbrush are noticeable imperfections that I have mentioned in the previous thread.
They also RobA commented about Path Blend script:
http://www.gimpchat.com/viewtopic.php?f=9&t=4066

I think with GIMP we could do so much more cool things with just some improvements.

Thanks for the info on the brush dynamics was just wondering how to achieve this in 2.8

So had a play with the new brush dynamics, each dynamic has a curve you can adjust similar to the colour curves. So i set my dynamics colour & size to fade and clicked on the bar which say mapping matrix this brings a drop down menu of setting, selected size. This should now bring up the curve tool for adjusting the brush dynamics, you'll need to check the one your after in this case fade. So with the fade curve now visiable adjusted it to this shape as shown in image (The adjustment is done just the same as the colour curves tool), then stroked path.
I only seemed to get half way along my path so then increased the fade length to 200% and this seemed to do the trick.

How much these settings will vary on different length path I don't know as I have not tried it.

OK, finally got something close using suggested methods of stroking paths

Nice K1TesseraEna.

Thanks for that he4rty.
I see that at least in my GIMP version (2.8.3), if you had previously marked boxes from "Mapping Matrix" the changes you make then from the curves are not applied. You need to uncheck all the boxes from "Mapping Matrix", and then check the appropriate boxes from the curves.
Oh yeah, with a graphics tablet is much easier make designs because you can configure pressure too:

@he4rty
i could not recreate this
i programmed the brush dynamic and everything, even found the curve but stroking the path didnt work for reasons i dont understand
did you use a tablet ?

at least K1te and YAFU had success

Try applying "Stroke Path" (With paintbrush tool and emulating brush dynamic) in the next file containing a path:
http://www.fileswap.com/dl/8k8w3DPW8u/path.xcf.html

After setting the dynamic, select paintbrush tool and you choose a large value of "Fade Length", around 1000.

thanks YAFU, im getting a result now