[Feature] Support variable fonts controls

[mezhgano]

Although i may be asking too much, but is it possible to add variable font controls?

Here is a good example of a variable font (Roboto Flex) and how its appearance can be changed using so called "Variable Axes":
https://fonts.google.com/specimen/Roboto+Flex/tester?preview.text=CINECRED

If you use the font in Adobe Illustrator, here is what the variable axes control panel looks like:

The reason:
One of the clients has approved specific variant of Roboto Flex font what can be achieved only by using variable capabilities, so now i'm looking for solution to use this variant in CineCred. Maybe it is possible to export or somehow "bake" this variant to separate font files and then just import these files to CineCred as usual. But for future needs, i think it will be cool to add variable controls directly to the letter styles panel.

[LoadingByte]

Thanks for the suggestion! I already thought about this feature multiple years ago, but in the end didn't implement it. However, this shouldn't be too difficult. Now that someone actually finds it useful, I'll add it to my ToDo list and hopefully ship it in the next big release.

[mezhgano]

Thanks.

Temporary solution that worked for me:

1. Adjust font variable axes in Adobe Illustrator, then select Export As > Format (SVG).
   In SVG export dialog click Show Code, text file opens, find font-variation-settings line and copy variable settings.

2. Use Python FontTools library to export static font file with desired variable settings by writing simple export script or use tools like this: https://github.com/jonpalmisc/vfit

3. Use static file(s) in CineCred.