make_bold

#!/usr/bin/env python
# coding=utf8
#
# Usually called in this directory via
# $ fontforge --script make_bold

# The resulting names in the font are ... bad, but we will rename it anyhow

# Inspiration from Thai Pangsakulyanont's https://github.com/dtinth/comic-mono-font,
# but fix a lot issues and changed weight by only 25 instead of 32 to have less clogged bowls.

import fontforge

font = fontforge.open('ComicShannsMono-Regular.sfd_modified')

# Repair some issues in source
font.selection.all()
font.removeOverlap() # For example THERE DOES NOT EXIST (u_2204) is broken
font.correctDirection()
target_width = 550
for g in font.selection.byGlyphs:
    # For example ntilde is 600 wide
    if g.width != target_width:
        # resize and recenter
        ( xmin, _, xmax, _ ) = g.boundingBox()
        bb_width = xmax - xmin
        if bb_width <= target_width:
            # Do not introduce negative lsb
            g.left_side_bearing = int((target_width - bb_width) / 2)
        g.width = target_width
font.selection.none()

# WIN line metrics obviously wrong, as Nerd Fonts sometimes prefers that, fix it already
font.os2_winascent = font.os2_typoascent
font.os2_windescent = -font.os2_typodescent
font.os2_use_typo_metrics = 1

font.generate('ComicShannsMono-Regular.otf')

# Create Bold face

font.fontname = 'ComicMono-Bold'
font.fullname = 'Comic Shanns Mono Bold'
font.weight = 'Bold'
font.os2_weight = 700
font.os2_stylemap = 1 << 5 # Bold
font.macstyle = 1 # Bold

# Do not enbolden graphics and Braille
font.encoding = 'UnicodeFull'
font.selection.select(('ranges',), 0x2500, 0xffff)
font.selection.select(('more',), '.notdef')
font.selection.invert()

# The boldening - albeit request to clean up self-intersections - produces
# a lot of problematic glyphs, we try to fix most
for g in font.selection.byGlyphs:
    g.simplify()
    g.changeWeight(25, 'LCG', 0, 0, 'squish', 1)
    g.removeOverlap()
    if g.selfIntersects():
        g.simplify(10, ('forcelines',), 0.0, 100, 0)
        if g.selfIntersects() and g.unicode != 0x05A:
            g.simplify(2, ('ignoreslopes','ignoreextrema','smoothcurves'), 0.2, 100, 100)

font.generate('ComicShannsMono-Bold.otf')
font.close()