Add visual tab to spyrogimp plugin
The current parameters for specifying a spirograph are not intuitive. Its difficult to use them to get a desired visual effect.
The attached patch (for the gimp 2.10 branch) adds a "Visual" tab that uses two visual metaphors:
- The petals of a flower - the number of petals, and how many petals to advance when drawing successive petals.
- A doughnut that has an inner "hole radius" and a width.
Specifying the amount of petals and the petal "skip" can lead to impossible shapes. For example, there is no pattern with 6 petals which advances 2 petals. Such a pattern would start with petal 1, and then go to petals 3 and 5, and back to 1 - without ever drawing the even petals. In such cases, I allow the user to specify the pattern, and I just draw two rotated shapes of 3 petals each.
If this patch is accepted, I will adapt it to work for the master branch as well.