From 139b14dbf62df3131f042ad258a69da3d44716e6 Mon Sep 17 00:00:00 2001
From: Nico Verbruggen <mail@nicoverbruggen.be>
Date: Sat, 14 Mar 2026 12:10:08 +0100
Subject: [PATCH] Tweak autohinting

---
 README.md | 21 +++++++++++++++++++++
 build.py  | 16 +++++++++++++++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 2018134..1bbf738 100644
--- a/README.md
+++ b/README.md
@@ -44,6 +44,8 @@ flatpak install flathub org.fontforge.FontForge
 
 ### macOS preparation
 
+#### System Python
+
 On macOS, if you're using the built-in version of Python (via Xcode), you may need to first add a folder to your `PATH` to make `font-line` available, like:
 
 ```bash
@@ -54,8 +56,27 @@ pip3 install fonttools font-line
 source ~/.zshrc
 ```
 
+#### Homebrew Python
+
+If you're using `brew install python`, pip requires a virtual environment:
+
+```bash
+brew install fontforge ttfautohint
+python3 -m venv .venv
+source .venv/bin/activate
+pip install fonttools
+```
+
 ## Building
 
+**Note**: If you're using `venv`, you will need to activate it first:
+
+```
+source .venv/bin/activate
+```
+
+If you are just using the system Python, you can skip that step and simply run:
+
 ```
 python3 build.py
 ```
diff --git a/build.py b/build.py
index baaaf1a..c779103 100755
--- a/build.py
+++ b/build.py
@@ -87,6 +87,20 @@ LINE_HEIGHT = 1.0
 SELECTION_HEIGHT = 1.3
 ASCENDER_RATIO = 0.8
 
+# Step 4: ttfautohint options (hinting for Kobo's FreeType renderer)
+# - Kobo uses FreeType grayscale, so the 1st char of --stem-width-mode
+#   (gray) is the one that matters. n=natural, q=quantized, s=strong.
+# - Remaining two chars are for GDI and DirectWrite (not used on Kobo).
+# - Other options are left at ttfautohint defaults; uncomment to override.
+AUTOHINT_OPTS = [
+    "--no-info",
+    "--stem-width-mode=nss",
+    # "--hinting-range-min=8",
+    # "--hinting-range-max=50",
+    # "--hinting-limit=200",
+    "--increase-x-height=0",
+]
+
 # Step 3: Naming and style metadata (used by the rename step)
 STYLE_MAP = {
     "Regular":    ("Regular",     "Book", 400),
@@ -642,7 +656,7 @@ def autohint_ttf(ttf_path):
 
     tmp_path = ttf_path + ".autohint.tmp"
     result = subprocess.run(
-        ["ttfautohint", "--no-info", ttf_path, tmp_path],
+        ["ttfautohint"] + AUTOHINT_OPTS + [ttf_path, tmp_path],
         capture_output=True, text=True,
     )
     if result.returncode != 0: