How to patch Symbols Only Nerd Font

[lukejanicke]

I would like to patch my own Symbols Nerd Font (the font file with just the Nerd Font symbols).

Is src/glyphs/original-source.otf the “font” to patch to create Symbols Nerd Font?

#479 discussed this question but closed after resolving a missing symbol.

src/unpatched-fonts/NerdFontsSymbolsOnly looks relevant but I don’t understand those files.

[Finii]

The Symbols Only font starts - like all other patched fonts - with a source font where all the symbols are patched into.
That source font is empty, so that in the end we have only all the icons in one font.
To give a somehow nice result the empty font needs to have some properties (like glyph size etc) defined, although it is empty.
To make maintenance more easy the font format is not ttf or otf but it is sfd

Empty source font src/unpatched-fonts/NerdFontsSymbolsOnly/NerdFontsSymbolsNerdFontBlank.sfd

The directory src/glyphs/ contains all the individual icon sets. They are not scaled and possibly unsorted. The raw icons.

To patch the Symbols only font you need something like

$ fontforge font-patcher --complete --ext ttf --variable-glyph-width src/unpatched-fonts/NerdFontsSymbolsOnly/NerdFontsSymbolsNerdFontBlank.sfd

You need to specify the --ext because probably you want a ttf (or otf) font as result and not a sfd. The patcher keeps the source font's type for the patched font if nothing is specified.

The config.cfg file you find with some unpatched source fonts (like the Symbols Only font) specifies which options need to be given for patching of that font; the automated release process uses this for example. So that is a good place to look for special options needed for that specific font.

[lukejanicke]

Follow-up...

I used fonttools to change the name of the --variable-width-glyphs font to Symbols Nerd Font Propo so I could install it alongside Symbols Nerd Font and Symbols Nerd Font Mono. A visual side-by-side comparison shows that they are not the same.

This suggests the patcher is correctly patching NerdFontsSymbolsNerdFontBlank.sfd with Propo symbols but not naming the generated font file accordingly.

[Finii]

The Symbols Only font comes in two flavours

• Nerd Font Mono
• Nerd Font Propo (which is called just Nerd Font only for this special case for backward compatibility and brevity)
• There is no real "Nerd Font" variant (i.e. were the icons extend into the next cell)

As I said, you need to give --variable-width-glyphs, for the normal Symbols Only font, or --mono (-s) for the Nerd Font Mono variant.

I'm not sure what giving neither produces for a font.

See also #1103 for an explanation of the three possible variants.

They should be the same. Is that right?

This is not entirely clear to me, it might differ in subtile ways, or be identical. I guess they differ. It comes also into play that the Symbols Only font qualifies as 'short-and-stubby' font which is patched differently from fonts of usual aspect ratio cells (where the cell is higher than it is wide).

If you are curious, just create both (with no options and with --variable), open both in fontforge and run a font-diff.

[Finii]

This suggests the patcher is correctly patching NerdFontsSymbolsNerdFontBlank.sfd with Propo symbols but not naming the generated font file accordingly

Yes, there is a specific rule for that in the patcher, lets see if I can find it...

[Finii]

Its here in this commit:
a7ecf07

[Finii]

Additional info:

Releases (or people) use the gotta-patch-em script to run the patcher script, and that does in fact patch the Symbols Only font three times, but trashes the version without any options, so that in the end we have only the Mono and the not-called-Propo-but-it-is-Propo one.

To make THAT happen we have the special rule added with this commit: 63db683

if args.nonmono and args.single:
    logger.warning("Specified contradicting --variable-width-glyphs and --use-single-width-glyph. Ignoring --variable-width-glyphs.")
    args.nonmono = False