Replicating a path

[Ottia Tuota]

Here is now a plugin that Rich suggested: "Replicate a path along another path". Perhaps it should still be called experimental. The basic usage is shown in the picture:


   


The main inputs are three paths:

• Source path
  
• Base path (a 2-anchor line segment)
  
• Target path
  

In this picture the Base path is the red line below the Source path. You can imagine that the Base path is mapped repeatedly onto the Target path, and the Source path just follows along. (But the transformed Base is not drawn by the plugin, only the Source.)

The task of the plugin is difficult. Often the results have faults. I shall make a separate post about this later (tomorrow). I don't know how I could help this. It is the user's responsibility to make the input paths such that they work well. To avoid difficulties:

• Use only gently curving Target paths. Avoid tight bends or fast changing curvatures.
  
• Use only smooth Target paths: no sharp points.
  
• Make sure that the Base path is close to the Source path and sufficiently long.
  

And even so, results may need manual corrections. But with reasonable input paths, the results are gratifying.

You can download the plugin from

http://kmarkku.arkku.net/Path_replicate_...aster.html

Unzip the .zip file and place the one file it contains (replicate_path_along_path.py) in your user's plug-ins folder. Then (re)start Gimp. Make a new image, and there the three input paths like above. In Gimp's menu, go to the Paths dock, right-click the Source path, and follow the link

Tools > Replicate > Replicate path along another path

and click. That opens the GUI of the plugin. I trust it to be so self-explanatory that you can go experimenting without further explanations.

You may wonder about the input 'tapering' which is in percents. It means this: For example, if you set tapering=10, each created copy of the Source will be 10% smaller than its predecessor. In addition, each copy will have some "inner tapering". Two pictures about this, the first with tapering=10 and the second with tapering=30:

   

The Source paths are on the left, and the Base paths coincide with their bottom lines.

Often you may wish to touch up the resulting path by joining close stroke ends. The first picture above is an example where it is good to do. You can do it with my plugin in

https://www.gimp-forum.net/Thread-Joinin...-of-a-path

or with Ofnuts' plugin Edit > Join strokes, contained in ofn-path-edits.

This new plugin is too complicated for me to have taken care of all failing points. Probably you will soon find cases where you just get some obscure error message. If so, please tell me. And post:

• The paths you used (an .xcf file)
  
• The parameters you used
  
• The error message as completely as possible
  

I don't  guarantee that I could make this much better. The problem is difficult. But I at least can try to correct most blatant errors.