Use variable fonts as source of truth, tweaks

README.md

@@ -10,12 +10,13 @@ To accomplish this, I wanted to start from the 9pt font, which I exported. Then,
 
 ## Project structure
 
-- `./src`: source .sfd font files (Newsreader 9pt, renamed to Readerly)
+- `./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
-- `./src_processed`: intermediate .sfd files after processing (generated)
+- `./src_processed`: intermediate files after instancing/processing (generated)
 - `./out`: final TTF fonts (generated)
 
 ## Building
@@ -24,9 +25,15 @@ To accomplish this, I wanted to start from the 9pt font, which I exported. Then,
 python3 build.py
 ```
 
-This uses the Flatpak version of FontForge to:
+This uses `fontTools.instancer` and the Flatpak version of FontForge to:
 
-1. Copy `./src` to `./src_processed`
+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 and update font names
+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