paulirish / numderspace

Font patcher to using shaping tricks to make it easier to pick out digit groups in numbers without commas

Numderscore

Allows the rendering of digit grouping (thousand separators) in contexts where you have some control over the font but don't want to (or can't) edit the text inline. It looks a bit like this:

This is achieved by adding font features to font files which enable outboard configuration of number formatting. The 'inserted' characters are baked into the font, so they don't affect copy/paste, syntax highlighting, etc.

Attribution: This project is primarily sh1boot's numderspace, which is based substantially on Numderline. My (paulirish) updates are adding dgun, auto-monospace detection, better test page and docs.

Feature Name	Example	Digit Grouping with…
dgsp	125 603.1415965	spaces within whole numbers
dgco	125,603.1415965	commas within whole numbers
dgun	125_603.141_596_5	underscores within whole numbers and decimals
dgdo	125.603,1415965	dots within whole numbers (and replacing literal dot with comma, use with caution)
dgdd	125.603,141.596.5	dots within whole numbers and decimals (and replacing literal dot with comma, use with caution)

Usage: Patch the font

Patch a font to add the extra stuff:

python3 patcher.py SomeFont.ttf

python3 patcher.py --help # see available options 

Usage: Apply the features

If you have CSS control with font-feature-settings over the font, apply this to the selectors you want formatted as such:

font-feature-settings: 'dgsp';

Various editors/tools allow enabling these font-features; see https://github.com/tonsky/FiraCode/wiki/How-to-enable-stylistic-sets (just change ss01 to dgsp, etc.)

To use it in a terminal (if you have one which supports ligation), you can use a monospaced font and pass --monospace to the patcher so that it will squeeze glyphs appropriately.

Usage might be configured with a line like: font=My Font with DigitGrouping:fontfeatures=dgsp or font_features My-Font-with-DigitGrouping dgsp, or, in fontconfig:

    <match target="pattern">
         <test name="family" compare="contains"><string>DigitGrouping</string></test>
         <edit name="fontfeatures" mode="append">
             <string>dgsp</string>
         </edit>
     </match>

Bake in grouping by default

Or… if all of that is too much hassle or isn't working out right, just bake in dgsp as the default, by passing --feature-name=calt to the patcher.