How to patch SymbolsOnly font?

[BEST8OY]

Hello
I want to patch this font but I get an error message

$ fontforge --script ./font-patcher --name SymbC --custom xxx.ttf ../../font/SymbolsNerdFont-Regular.ttf  
Copyright (c) 2000-2024. See AUTHORS for Contributors.
 License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
 with many parts BSD <http://fontforge.org/license.html>. Please read LICENSE.
 Version: 20230101
 Based on sources from 2024-04-05 14:41 UTC-ML-D-GDK3.
Nerd Fonts Patcher v3.3.0 (4.16.1) (ff 20230101)
The glyph named heart is mapped to U+F08D0.
  But its name indicates it should be mapped to U+2665.
CRITICAL: Can not detect sane font width

I would appreciate any kind of help
Thanks.

[Finii]

The patcher expects a font with latin letters. It calculates a likely "cell size" by the size of specific latin letters and weights them in some way. If there are no letters (A-Z and a-z) it can not compute the "cell size" und thus not create a Nerd Font.

An exception is when the input font is completely empty. In that case the script decides on the "cell size" by whole-font properties.

A solution for you would be to take the (empty) SymbolsOnly input font (from under /src/unpatched-fonts/NerdFontSymbolsOnly/ and patch that with --complete --vari and at the same time add your own icons with --custom ....

Edit: Use this as input font https://github.com/ryanoasis/nerd-fonts/blob/master/src/unpatched-fonts/NerdFontsSymbolsOnly/NerdFontsSymbolsNerdFontBlank.sfd

[BEST8OY]

Yes
Thank you. It worked really well.

During all the testes I've done I figured that --custom when used with --variable-width-glyphs it messes with the bearings but when --variable-width-glyphs is used with the internal glyphs option of font-patcher it doesn't cause this issue!
So,
-c --variable-width-glyphs everything all right!
-c --custom --variable-width-glyphs messes with the bearings!

Why is that? Is there any plan for it to get fixed in future?

[Finii]

I guess I do not really understand all your problems, but then probably I would need your xxxt.ttf to really examine it, and some example invocations that went well or not well; so that I could really reproduce the issues.

In principle --custom is not a core feature of the patcher and the support is rather ... limited. I used it once for a project (https://github.com/adam7/delugia-code) but that has a specifically hand-crafted custom font.

If I could understand the problem it can for sure be fixed. Not sure if that (fixing) is needed, noone ever complained so either it is ok or it's never used ;-)

[BEST8OY]

The font is Segoe Fluent Icons by Microsoft.
I installed it from AUR through a package.(V1.22)
The one in Microsoft website is v1.0
I thought maybe it's not okay to share it! (License stuff; I don't know much)
But here we go
ttf.zip
If it not okay, please do tell me to remove it or if it's possible do so yourself.
Thanks.