How to use Glyphs 3 to set the lowest y value of a character set to the descender (i.e. size to fit)

Hi!

First off, congrats on the great job you’ve done with the app. I’m actually not a font designer but have still found the app intuitive and very easy to use.

I have a couple of questions. I’m an iOS app developer and have a font that I’m including in one of my apps that has a very large descender value (well below any character in the character set).

In the image below, you can see there is a lot of excess space at the bottom of the text and the font is quite small.

Screen Shot 2021-05-14 at 11.31.41 PM

My ultimate question is, is there a way in Glyphs to find the lowest y point a character reaches for the entire character set and then set the descender to that value? Would also like to do this for the ascender as well (for the highest y point). Essentially I’m wanting to “size to fit” the font so that it doesn’t have too much excess space at the bottom or top.

Also wanted to ask, for my purpose of just editing fonts in the way I described above, would Glyphs Mini serve my purpose? I think all of the fonts I’m dealing with only have simple scripts (some might have Chinese lettering in image form, not sure) and the files don’t include entire families and I’m pretty sure they satisfy “Single Master OpenType Fonts”. Right now am using the full version trial but will need to make a decision on which edition fits me best when the 30 days runs out.

Thanks for your time!

Finding the maximum bounds of a font is currently not possible but there is a script for that. As you can’t run scripts in Glyphs Mini, that would be a reason to get the full app.
And in the full app, you have much more control over the vertical metrics.

But I would just set the vertical metrics so that you like the line spacing, size and vertical position when you use it in the app. You can have stuff outside of ascender and descender (try Zapfino).

Great, thanks!