Swap Glyph when font size is small

Hi! I need to swap glyph when font size smaller than 20pt. There is the way to do that?

No. The user has to do this.

What you can do is create different font instances with an Optical Size parameter (explanation in the Appendix of the Handbook). Software has to support it though. Adobe InDesign, theoretically, can automatically switch between optical sizes. I am not aware of any other apps that work with Optical Sizes, unless you want to count macOS system fonts.

The problem with Optical Sizes is that they do not take viewing distance into account. So it is better to leave this to the user.

Understood. Thank you!