Font Leading changing, even when I export with the same metrics as the original source

Glyphs
1

Hello,
I have a problem exporting exact copy of a font.
I opened the original OTF font file and added couple of missing glyphs and added a new name, I haven’t changed anything else.
Now when I try to export the new OTF file, the default Leading is changed. For ex. in the Pages app, the new generated font has bigger line spacing than the original.
Can you please help, what might be the problem?

2

Did you add glyphs that were higher or lower than the others?

What is your linespacing setting in Pages?

Which macOS are you running?

3
  1. I tested and it happens even if I just re-export the font, without adding any new glyphs.
  2. It’s set to 0 by default.
  3. Mac OS 15.5
4

Could this be related to Glyphs 2 exporting with different font leading than Glyphs 3? I can’t remember the details, but I encountered a similar change when I opened an older project in Glyphs 3. I think it was related to the OS/2 line gap. @mekkablue I’m sure you can explain the details.

5

Generally: you do not open, change and save a font file with a font editor (unless you do this with a very specific tool like OTMaster). You reverse-engineer a new file, make changes, and compile a completely new font binary.

The info inside a font file is stored as ascender, descender and line gap in the OS/2 and hhea tables. Common consensus today (has not always been this way) is that these values should be in sync. The OS/2 table holds additional winAscent and winDescent values for the clipping area if a software requires this information. Also, the Use Typo Metrics bit in the OS/2 fsSelection must be on in modern fonts. More details in the Vertical Metrics tutorial.

When you open a compiled font, Glyphs reverse engineers the vertical metrics and puts them in File > Font Info > Masters > Custom Parameters. If they are deactivated or deleted, Glyphs recalculates them or falls back to defaults, and those may be different from original settings in the file. I do not know how old the font is that you edited. (Also make sure your EULA allows editing and subsequent installation on the devices you intend it for.)

A possible scenario is that the vertical metrics in Font Info arwe not what they were before. You can compare the two font files with FontTableViewer, a free app you can get through the Get Glyphs page (scroll down to the tools), to see where the two diverge.

2 Likes
6

Could you send me the original .otf font for testing?

7

I have send it as a zip archive in direct message.

8

Did you send it to me or Rainer (@mekkablue)?