I would like to read continous color gradient from the image using the path ( white line on the image).

enter image description here

I know that I can read palette but I want to read all values in a specific order to create function from them. I can do it manually in gimp by color picker but it would be faster to mark a path and read all values at once. Is it possible or should I write a script to do it?

================= edit =========================

this is confirmation that Wolff's answer is good. I have made a screen copy of original program ( below). So the gradient has 7 segments from magenta, black, red, yellow, green, cyan, blue, to magenta[

enter image description here

and here is the result of my c/gnuplot program

enter image description here

enter image description here

1 Answer 1


I'm not a GIMP user, but to me it seems improbable that GIMP would have such a function out of the box.

Sure it could be scripted, but if you measure pixel by pixel along a path, you will get all sorts of inconsistencies because of noise and anti-aliasing in the image. Also the measurements would depend a lot on the exact path you draw. The path you have drawn doesn't seem to follow the shape of the fractal. In other words, the gradient wouldn't be smooth.

To me it seems that the gradient simply starts with black, goes through the whole RGB spectrum from red to magenta and then ends with black so it can be repeated:

  • path should go along spiral structures of the fractal. It is not my image so I can read color manually, some errors are possible. I have found a script : gimpchat.com/viewtopic.php?f=9&t=14743&start=10
    – Adam
    Sep 19, 2020 at 12:05
  • if the data will be noisy I can smooth it like linas gradient : gitlab.com/adammajewski/color_gradient#linas-colormap
    – Adam
    Sep 19, 2020 at 12:07
  • 1
    But you do agree, that it's basically the gradient I've shown, right? So this is not for graphic design, but for scientific use?
    – Wolff
    Sep 19, 2020 at 12:26
  • 2
    I just mean, if it's for science, such a measurement wouldn't be very scientific anyway. The image is low res. The pattern of the fractal continues endlessly into the detail and those details pollute the appearance of the pixels. Is it even possible for you to draw the path to follow the spiral shape precisely? Wouldn't it be just as precise to just "guess" the gradient like a designer would?
    – Wolff
    Sep 19, 2020 at 13:08
  • 1
    I don't fully understand what you say. I've added the RGB values of the gradient. They just fade linearly from point to point. Does this help?
    – Wolff
    Sep 19, 2020 at 13:51

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