Update hinting again

VERSION

@@ -1 +1 @@
-1.4
+1.5

build.py

@@ -91,16 +91,30 @@ 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.
+#   matters: n=natural (least distortion), q=quantized, s=strong.
-# - Remaining two chars are for GDI and DirectWrite (not used on Kobo).
+# - x-height snapping is disabled to avoid inconsistent glyph heights.
-# - Other options are left at ttfautohint defaults; uncomment to override.
 AUTOHINT_OPTS = [
     "--no-info",
-    "--stem-width-mode=qss",
+    "--stem-width-mode=nss",
-    # "--hinting-range-min=8",
+    "--increase-x-height=0",
-    # "--hinting-range-max=50",
+    '--x-height-snapping-exceptions=-',
-    # "--hinting-limit=200",
+]
-    "--increase-x-height=14",
+
+# Baseline alignment: deepen the bottom anti-aliasing of non-serifed
+# glyphs via hinting-only touch deltas (no outline changes).  This
+# shifts their bottom points down during rasterization so they produce
+# more gray below the baseline, visually matching serifed characters.
+# Each entry is (shift_px, ppem_min, ppem_max).  Shifts are in pixels
+# (multiples of 1/8, max 1.0).  Set to empty list to disable.
+BASELINE_HINT_SHIFTS = [
+    (0.125, 6, 53),
+]
+
+# Per-glyph Y ceiling: cap the top of specific glyphs to reduce
+# oversized or awkward serifs.  (glyph_name, max_y)
+# Points above max_y are clamped down to max_y.
+GLYPH_Y_CEILING = [
+    ("u", 1062),  # flatten tiny top serif tips to platform level
 ]
 
 # Explicit kern pairs: (left_glyph, right_glyph, kern_value_in_units).
@@ -752,6 +766,79 @@ def add_kern_pairs(ttf_path):
     print(f"  Added {count} kern pair(s) to GPOS")
 
 
+
+def apply_glyph_y_ceiling(ttf_path):
+    """Clamp glyph points above a Y ceiling down to the ceiling value."""
+    if not GLYPH_Y_CEILING:
+        return
+
+    from fontTools.ttLib import TTFont
+    font = TTFont(ttf_path)
+    glyf = font["glyf"]
+    modified = []
+
+    for glyph_name, max_y in GLYPH_Y_CEILING:
+        g = glyf.get(glyph_name)
+        if not g or not g.numberOfContours or g.numberOfContours <= 0:
+            continue
+        coords = g.coordinates
+        clamped = 0
+        for j in range(len(coords)):
+            if coords[j][1] > max_y:
+                coords[j] = (coords[j][0], max_y)
+                clamped += 1
+        if clamped:
+            modified.append(f"{glyph_name}({clamped}pts)")
+
+    if modified:
+        font.save(ttf_path)
+        print(f"  Clamped Y ceiling: {', '.join(modified)}")
+    font.close()
+
+
+def _generate_baseline_shift_ctrl(ttf_path):
+    """Generate touch deltas to deepen bottom anti-aliasing of non-serifed glyphs.
+
+    For lowercase glyphs without a flat baseline (no serif foot), shifts
+    the bottom-most points down during rasterization.  Uses graduated
+    shifts from BASELINE_HINT_SHIFTS — stronger at small ppem sizes
+    where alignment is most noticeable.  No outline changes.
+    """
+    if not BASELINE_HINT_SHIFTS:
+        return ""
+
+    from fontTools.ttLib import TTFont
+    font = TTFont(ttf_path)
+    glyf = font["glyf"]
+    cmap = font.getBestCmap()
+    lines = []
+
+    for char in "abcdefghijklmnopqrstuvwxyz":
+        code = ord(char)
+        if code not in cmap:
+            continue
+        name = cmap[code]
+        g = glyf[name]
+        if not g.numberOfContours or g.numberOfContours <= 0:
+            continue
+        coords = g.coordinates
+        ys = set(c[1] for c in coords)
+        if 0 in ys:
+            continue  # has serif baseline
+        bottom_pts = [i for i, (x, y) in enumerate(coords) if y <= 0]
+        if not bottom_pts:
+            continue
+        pts_str = ", ".join(str(p) for p in bottom_pts)
+        for shift_px, ppem_min, ppem_max in BASELINE_HINT_SHIFTS:
+            shift = -abs(shift_px)
+            lines.append(
+                f"{name} touch {pts_str} yshift {shift:.3f} @ {ppem_min}-{ppem_max}"
+            )
+
+    font.close()
+    return "\n".join(lines)
+
+
 def autohint_ttf(ttf_path):
     """Run ttfautohint to add proper TrueType hinting.
 
@@ -766,16 +853,34 @@ def autohint_ttf(ttf_path):
     hinting, which may handle sub-baseline overshoots more gracefully.
     The resulting bytecode is baked into the font, so FreeType uses
     the TrueType interpreter instead of falling back to auto-hinting.
+
+    Additionally generates per-font touch deltas to deepen the
+    baseline anti-aliasing of non-serifed glyphs.
     """
     if not shutil.which("ttfautohint"):
         print("  [warn] ttfautohint not found, skipping", file=sys.stderr)
         return
 
+    # Generate control instructions for this specific font's points
+    ctrl_text = _generate_baseline_shift_ctrl(ttf_path)
+    ctrl_path = ttf_path + ".ctrl.tmp"
+    ctrl_count = 0
+    opts = list(AUTOHINT_OPTS)
+    if ctrl_text:
+        with open(ctrl_path, "w") as f:
+            f.write(ctrl_text)
+        opts += [f"--control-file={ctrl_path}"]
+        ctrl_count = ctrl_text.count("\n") + 1
+
     tmp_path = ttf_path + ".autohint.tmp"
     result = subprocess.run(
-        ["ttfautohint"] + AUTOHINT_OPTS + [ttf_path, tmp_path],
+        ["ttfautohint"] + opts + [ttf_path, tmp_path],
         capture_output=True, text=True,
     )
+
+    if os.path.exists(ctrl_path):
+        os.remove(ctrl_path)
+
     if result.returncode != 0:
         print(f"  [warn] ttfautohint failed: {result.stderr.strip()}", file=sys.stderr)
         if os.path.exists(tmp_path):
@@ -783,7 +888,10 @@ def autohint_ttf(ttf_path):
         return
 
     os.replace(tmp_path, ttf_path)
-    print(f"  Autohinted with ttfautohint")
+    hint_msg = "Autohinted with ttfautohint"
+    if ctrl_count:
+        hint_msg += f" ({ctrl_count} serif control hints)"
+    print(f"  {hint_msg}")
 
 
 # ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
@@ -815,6 +923,9 @@ KOBOFIX_URL = (
 
 def _download_kobofix(dest):
     """Download kobofix.py if not already cached."""
+    if os.path.isfile(dest):
+        print(f"  Using cached kobofix.py")
+        return
     import urllib.request
     print(f"  Downloading kobofix.py ...")
     urllib.request.urlretrieve(KOBOFIX_URL, dest)
@@ -857,9 +968,18 @@ def main():
     family   = DEFAULT_FAMILY
     outline_fix  = True
 
+    # --name "Foo" sets the family name directly
+    if "--name" in sys.argv:
+        idx = sys.argv.index("--name")
+        if idx + 1 < len(sys.argv):
+            family = sys.argv[idx + 1]
+        else:
+            print("ERROR: --name requires a value", file=sys.stderr)
+            sys.exit(1)
+
     if "--customize" in sys.argv:
         print()
-        family = input(f"  Font family name [{DEFAULT_FAMILY}]: ").strip() or DEFAULT_FAMILY
+        family = input(f"  Font family name [{family}]: ").strip() or family
         outline_input = input("  Apply outline fixes (remove overlaps + zero-area cleanup)? [Y/n]: ").strip().lower()
         outline_fix = outline_input not in ("n", "no")
 
@@ -977,6 +1097,7 @@ def _build(tmp_dir, family=DEFAULT_FAMILY, outline_fix=True):
             clean_ttf_degenerate_contours(ttf_path)
         fix_ttf_style_flags(ttf_path, style_suffix)
         add_kern_pairs(ttf_path)
+        apply_glyph_y_ceiling(ttf_path)
         autohint_ttf(ttf_path)