Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Change color intensity stroking along a path
#1
I wonder if one can use gimp to change a colour intensity along stroking a path depending on the length of the path : from zero saturation on the start of the path to full saturation at the end of the path.
Reply
#2
(09-25-2021, 08:23 AM)denzjos Wrote: I wonder if one can use gimp to change a colour intensity along stroking a path depending on the length of the path : from zero saturation on the start of the path to full saturation at the end of the path.

The GEGL saturation tool Color -> Saturation is a bit peculiar, the scale is 0 to 10, however zero is desaturated so, 

You could try stroking the path, with the paint tool, using the  dynamic color from gradient and a suitable fade length.

The gradient from the-colour-used to the-colour-used desaturated. This example, the primaries desaturated in separate image to colour pick.

   

Someone will probably come up with a script for this, I thought I remembered one but not able to find it.
Reply
#3
Rich, thank you for the reply. Dynamic color from gradient help me a little but is not enough to color long paths, but just learned something new. Thanks.
Reply
#4
How long are your paths ?

You can get the path length using Ofnuts path tools and set the fade length to that value.

   

Maybe Ofnuts will have a plug-in somewhere in his repertoire.
Reply
#5
Hi Rich, it's the intention to play around with the Ottia Tuota parametric curves. One of the things I want to exam is to use color blending along the length of a path to create tunnel vision images. So, as an example, lighter from the beginning of a path and darker to the end of the path.
Reply
#6
(09-25-2021, 05:21 PM)denzjos Wrote: Hi Rich, it's the intention to play around with the Ottia Tuota parametric curves. One of the things I want to exam is to use color blending along the length of a path to create tunnel vision images. So, as an example, lighter from the beginning of a path and darker to the end of the path.

You always have some great ideas. Regardless of what you eventually get to stroke the path, it might still be useful to get the path information from Ofnuts path tools. To me looks like both curves have approximately the same starting point.

   
Reply
#7
This goes in the direction I want for one color range (fading)
   
Reply
#8
I send out a firefly a few times on the same path with some brush dynamics support (click on the image for full view):
   
Reply
#9
Very hard programmatically if is is a single stroke because there is no API in Gimp to set the fade length...

I don't know how OT's paths look but if they are a sequence of closed strokes, you can use my various scripts to

1) Decompose the path into individual strokes (ofn-path-edits(Break path apart))
2) Stroke each path with a color taken from a gradient (ofn-stroke-fill-paths )
Reply
#10
(09-26-2021, 09:24 PM)Ofnuts Wrote: Very hard programmatically if is is a single stroke because there is no API in Gimp to set the fade length...

I don't know how OT's paths look but if they are a sequence of closed strokes, you can use my various scripts to

1) Decompose the path into individual strokes (ofn-path-edits(Break path apart))
2) Stroke each path with a color taken from a gradient (ofn-stroke-fill-paths )

If we are talking about the paths generated by the Simple harmonograph plugin, then: Each path is a single open stroke. Exception: If Skip=0 and there is no damping then the stroke is closed.

But that denjos' path is one open very long stroke, containing a large number of anchors.
Reply


Forum Jump: