Added an in-image key with labels for external rays to my Mandelbrot Perturbator GTK project.
Need to make it optional and/or detachable to a second page in PDF export because some images might have long ray labels (100s-1000s of characters) and having them all on the image will be distracting.
Got detached key working in both PNG (an extra image file with extension ".key.png" in place of ".png") and PDF (a second page in the same file) export. Overlay on image is another option, as is having no key at all (the default mode).
I adjusted the dashing patterns for each ray by hand in the GUI, this would be something nice to automate because it's very tedious mouse clickery.
The way I'm showing the text makes it non-selectable in the PDF, need to fix that too... hopefully it's something simple in my use of the Cairo API.