readerly/README.md

Readerly

Readerly is modified font based on Newsreader, while attempting to be metrically very similar to Bookerly, the default font on Kindle devices, to provide a similar reading experience.

When I was doing my usual font tweaking for my ebook-fonts repository, I stumbled upon variable fonts exporting. Doing this for Newsreader gave me some interesting results at small optical sizes: the font was now reminding me of Bookerly.

I asked myself the question: how close can we get to the metrics of Bookerly while still retaining Newsreader and keeping the font licensed under the OFL, and maybe making some mild manual edits?

The goal was to get a metrically/visually similar font, without actually copying glyphs or anything that would infringe upon the rights of the original creators; after all, Newsreader is a very beautiful font as a starting point.

To get to the final result, I decided to use the variable font and work on it. The original is located in ./src and is available under the same OFL as the end result.

Project structure

• ./src: Newsreader variable font TTFs (source of truth)
• ./scripts: FontForge Python scripts applied during the build
  • scale.py: scales lowercase glyphs vertically to increase x-height
  • metrics.py: sets vertical metrics (OS/2 Typo, Win, hhea)
  • lineheight.py: adjusts OS/2 Typo metrics to control line spacing
  • rename.py: updates font name metadata from Newsreader to Readerly
  • version.py: sets the font version from ./VERSION
• ./out/sfd: FontForge source files (generated)
• ./out/ttf: final TTF fonts (generated)

Building

python3 build.py

This uses fontTools.instancer and the Flatpak version of FontForge to:

1. Instance the variable fonts into static TTFs at configured axis values (opsz, wght)
2. Scale lowercase glyphs (configurable in scripts/scale.py)
3. Set vertical metrics, adjust line height, and update font names
4. Export to TTF with old-style kerning in ./out

Variant configuration (in build.py):

• Regular: wght=400, opsz=9
• Bold: wght=550, opsz=9
• Italic: wght=400, opsz=9
• BoldItalic: wght=550, opsz=9