lite-xl-fontseek

A cross-platform font searching and loading plugin solution for Lite XL.

This project is the start (experiment) of a support library that facilitates searching and loading fonts without having to rely on external dependencies like font-config. To achieve this a font meta data parser written in Lua is used to generate a list of fonts with details like family and subfamily. This list is later cached into a persistent file storage that can be quickly loaded on each session startup for easy font lookups.

Installation

To install clone this repository to your user directory as shown below. Also make sure to clone to the right directory name which is fontseek.

cd ~/.config/lite-xl/
git clone https://github.com/jgmdev/lite-xl-fontseek plugins/fontseek

Usage

For the moment it allows searching and loading multiple fonts into a font group. The following interface provides functionality to load multiple fonts:

---@alias FontInfo.style
---|>'"regular"'
---| '"bold"'
---| '"italic"'
---| '"bold italic"'
---| '"thin"'
---| '"medium"'
---| '"light"'
---| '"black"'
---| '"condensed"'
---| '"oblique"'
---| '"bold oblique"'
---| '"extra nold"'
---| '"Extra bold italic"'
---| '"bold condensed"'

---@class plugins.fontseek.font
---@field public name string
---@field public style FontInfo.style
---@field public monospaced boolean
---@field public options renderer.fontoptions

---Search for fonts and loads them it into the given table field.
---@param t table A table where the font resides
---@param field string Name or idx where the font is stored
---@param fonts_list plugins.fontseek.font[] List of fonts to search and load
---@param size number Desired overall font size without SCALE applied
function fontseek.load(t, field, fonts_list, size) end

Example Usage

local fontseek = require "plugins.fontseek"

-- font options
local options = { antialiasing = "subpixel", hinting = "slight" }

-- Load the fonts without having to know the path or exact file name.
-- this may not work perfectly, who knows :) ...
fontseek.load(style, "font", {
  { name = "open sans", style = "regular", options = options },
  { name = "emoji", options = options }
}, 16)

fontseek.load(style, "code_font", {
  { name = "noto sans", style = "medium", monospaced = true, options = options },
  { name = "emoji", options = options },
  { name = "nonicons", options = options },
}, 15)

Extras

Besides providing a basic api that lets you load your fonts it also adds commands that allow you to swap the current text and code fonts from an "easy to search" CommandView list:

Commands

• font-seek:set-code-font - change the size and font of code
• font-seek:set-text-font - change the size and font of other text
• font-seek:rebuild-cache - re-generate the font cache

Future Plans?

Expand the functionality provided (if needed) to implement a basic font picker dialog for the widgets library.

Technical Details and Possible Drawbacks

The first time the plugin loads will scan all your system available plugins. With 3000+ font files it takes around 1.5 seconds, when done within the context of a coroutine to prevent startup block it can take from 3 to 5 seconds. This isn't bad taking into consideration that Lua is parsing all the 3000+ font files metadata.

The slow part is the second stage, which is to identify if a font is monospaced or not. This is because we need to load the font glyphs and compare the width from at least one character to another. We are also performing this task in the context of a coroutine and with the 3000+ fonts figures this takes 60+ seconds to complete.

After the above two stages we cache the list of fonts by storing it into a serialized Lua table. Loading this Lua table with the 3000+ fonts is basically performed instantly by Lua, so caching boosts subsequent startups while giving immediate lookup access to the list of installed fonts.