Add --prefix option and update font metadata based on that

Rather than trying to infer the font name and weight from the filename,
ligaturizer now uses the metadata embedded in the font file and sticks
the desired prefix onto it.

Makefile

@@ -1,6 +1,6 @@
 # Alternate options for ligaturize.py.
 # Run `fontforge -lang=py ligaturize.py --help` for details.
-LIGATURIZE_OPTS=
+LIGATURIZE_OPTS=--prefix=Liga
 # LIGATURIZE_OPTS+=" --copy-character-glyphs"
 # LIGATURIZE_OPTS+=" --scale-character-glyphs-threshold=0.0"
 # LIGATURIZE_OPTS+=" --scale-character-glyphs-threshold=2.0"

ligaturize.py

@@ -9,6 +9,8 @@
 #
 # See ligatures.py for a list of all the ligatures that will be copied.
 
+from __future__ import print_function
+
 import fontforge
 import psMat
 import os
@@ -34,37 +36,6 @@ def get_ligature_source(fontname):
         return 'fira/FiraCode-Bold.otf'
     return 'fira/FiraCode-Regular.otf'
 
-def get_output_font_details(fontpath):
-    fontname = path.splitext(path.basename(fontpath))[0]
-    if '-' in fontname:
-        [family, weight] = fontname.split('-', 1)
-    else:
-        [family, weight] = [fontname, 'Regular']
-    return {
-        'filename': fontpath,
-        'fontname': '%s-%s' % (family, weight),
-        'fullname': '%s %s' % (split_camel_case(family), split_camel_case(weight)),
-        'familyname': family,
-        'copyright_add': COPYRIGHT,
-        'unique_id': '%s-%s' % (family, weight),
-    }
-
-# Add spaces to UpperCamelCase: 'DVCode' -> 'DV Code'
-def split_camel_case(str):
-    acc = ''
-    for (i, ch) in enumerate(str):
-        prevIsSpace = i > 0 and acc[-1] == ' '
-        nextIsLower = i + 1 < len(str) and str[i + 1].islower()
-        isLast = i + 1 == len(str)
-        if i != 0 and ch.isupper() and (nextIsLower or isLast) and not prevIsSpace:
-            acc += ' ' + ch
-        elif ch == '-' or ch == '_' or ch == '.':
-            acc += ' '
-        else:
-            acc += ch
-    return acc
-
-
 class LigatureCreator(object):
 
     def __init__(self, font, firacode, opts):
@@ -238,14 +209,14 @@ def add_calt(self, calt_name, subtable_name, spec, **kwargs):
         self.font.addContextualSubtable(calt_name, subtable_name, 'glyph', spec)
 
 
-
-def change_font_names(font, fontname, fullname, familyname, copyright_add, unique_id):
-    font.fontname = fontname
-    font.fullname = fullname
-    font.familyname = familyname
-    font.copyright += copyright_add
+def update_font_metadata(font, prefix):
+    font.fontname = "%s%s" % (prefix, font.fontname)
+    font.fullname = "%s %s" % (prefix, font.fullname)
+    font.familyname = "%s %s" % (prefix, font.familyname)
+    font.copyright += COPYRIGHT
     font.sfnt_names = tuple(
-        (row[0], 'UniqueID', unique_id) if row[1] == 'UniqueID' else row
+        (row[0], 'UniqueID', '%s-%s' % (prefix, row[2]))
+        if row[1] == 'UniqueID' else row
         for row in font.sfnt_names
     )
 
@@ -276,21 +247,27 @@ def parse_args():
              " they are at least 10%% wider or narrower. A value of 0 will scale"
              " all copied character glyphs; a value of 2 effectively disables"
              " character glyph scaling.")
+    parser.add_argument("--prefix",
+        type=str, default="Liga ",
+        help="String to prefix the name of the generated font with.")
     return parser.parse_args()
 
 args = parse_args()
 
-output_font = get_output_font_details(args.output_font_path)
+# print('Converting %s to %s using ligatures from %s' % (
+#     args.input_font_path, args.output_font_path, args.ligature_font_path))
 font = fontforge.open(args.input_font_path)
 
 if args.ligature_font_path:
     ligature_font_path = args.ligature_font_path
 else:
-    ligature_font_path = get_ligature_source(output_font['fontname'])
+    ligature_font_path = get_ligature_source(font.fontname)
 
 print('Reading ligatures from %s' % ligature_font_path)
 firacode = fontforge.open(ligature_font_path)
 
+update_font_metadata(font, args.prefix)
+
 creator = LigatureCreator(font, firacode, args)
 ligature_length = lambda lig: len(lig['chars'])
 for lig_spec in sorted(ligatures, key = ligature_length):
@@ -300,17 +277,10 @@ def parse_args():
         print('Exception while adding ligature: {}'.format(lig_spec))
         raise
 
-change_font_names(font, output_font['fontname'],
-                        output_font['fullname'],
-                        output_font['familyname'],
-                        output_font['copyright_add'],
-                        output_font['unique_id'])
-
 # Work around a bug in Fontforge where the underline height is subtracted from
 # the underline width when you call generate().
 font.upos += font.uwidth
 
 # Generate font & move to output directory
-output_name = output_font['filename']
 font.generate(args.output_font_path)
-print "Generated ligaturized font %s in %s" % (output_font['fullname'], args.output_font_path)
+print("Generated ligaturized font %s in %s" % (font.fullname, args.output_font_path))