Static NUMBER_FONT

static NUMBER_FONT: &[u8]

This font is only guaranteed to work on numbers.

Font

• Open Sans - Google Fonts
  • Links to: https://github.com/googlefonts/opensans
  • License: Open Font License.
• Alternatively we could use DejaVuSans.ttf
• The text-to-png includes a font if you don’t chose one yourself, we could use that one.

Minimize size

We only need to render digits so we remove unnecessary stuff, see: filesize - Way to reduce size of .ttf fonts? - Stack Overflow