RFC: Add a list of all fonts as JSON file to the frontend

[MichaelKreil]

We should add a list of the available fonts to the frontend. Not only for Maputnik, but also for our own frontend tools.

For example, let's use a subset of "Fira Sans" and generate glyphs for:

• italic / non-italic
• bold / normal
• "Fira Sans" / "Fira Sans Condensed"

The folder /assets/fonts/ would look like this:

fira_sans_bold/*.pbf
fira_sans_bold_italic/*.pbf
fira_sans_condensed_bold/*.pbf
fira_sans_condensed_bold_italic/*.pbf
fira_sans_condensed_italic/*.pbf
fira_sans_condensed_regular/*.pbf
fira_sans_italic/*.pbf
fira_sans_regular/*.pbf
font_families.json
fonts.json

The default fonts.json used by Maputnik would just be an array of these 8 folder names:

[
   "fira_sans_bold",
   "fira_sans_bold_italic",
   "fira_sans_condensed_bold",
   "fira_sans_condensed_bold_italic",
   "fira_sans_condensed_italic",
   "fira_sans_condensed_regular",
   "fira_sans_italic",
   "fira_sans_regular"
]

But for our own frontends, we can generate an additional JSON font_families.json with more information. I suggest this format:

{
   "fira_sans": {
      "name": "Fira Sans",
      "fontFace": {
         "fira_sans_bold": { "name": "Bold", "italic": false, "weight": 700 },
         "fira_sans_bold_italic": { "name": "Bold Italic", "italic": true, "weight": 700 },
         "fira_sans_italic": { "name": "Italic", "italic": true, "weight": 400 },
         "fira_sans_regular": { "name": "Regular", "italic": false, "weight": 400 }
      }
   },
   "fira_sans_condensed": {
      "name": "Fira Sans Condensed",
      "fontFace": {
         "fira_sans_condensed_bold": { "name": "Bold", "italic": false, "weight": 700 },
         "fira_sans_condensed_bold_italic": { "name": "Bold Italic", "italic": true, "weight": 700 },
         "fira_sans_condensed_italic": { "name": "Italic", "italic": true, "weight": 400 },
         "fira_sans_condensed_regular": { "name": "Regular", "italic": false, "weight": 400 }
      }
   }
}

What do you think?

[yetzt]

looks good to me

[MichaelKreil]

https://github.com/versatiles-org/versatiles-fonts/releases/tag/v1.1.0