Use ttx to edit font metadata. Slow, wastes 10 min, but works.

README.md

@@ -34,3 +34,45 @@ There is no dependency other than [`nototools`](https://github.com/googlefonts/n
 |                            |                                                                                      |
 
 
+<!--
+1891 glyphs -> GSUB LookupIndex 1293 fails
+1575 glyphs -> GSUB LookupIndex 646 fails. Max Lookuptable size = 1651
+(NoSubjoined) 168 code points, 688 glpyhs -> GSUB LookupCount 1680
+
+../venv_fonty/bin/pyftsubset  NotoSerifTibetan-Regular.ttf \
+    --unicodes=U+0F00-0F8C,U+0F90,U+0F94,U+0F95,U+0F97,U+0F9F,U+0FA1,U+0FA3,U+0FA4,\
+    U+0FA6,U+0FA9,U+0FAB,U+0FAD,U+0FAF,U+0FB1-0FB3,U+0FB06-0FB8,U+0FBE-0FDA
+=> gives 181 codepoints, 1380 glyphs, 401KB size, GSUB LookupCount 915
+
+In comparison, Devanagari has GSUB LookupCount = 120 just!
+
+--unicodes=U+0F00-0F68,U+0F6B-0F87,U+0F90,U+0F94,U+0F95,U+0F97,U+0F
+9F,U+0FA1,U+0FA3,U+0FA4,U+0FA6,U+0FA9,U+0FAB,U+0FAD,U+0FAF,U+0FB1-0FB3,U+0FB06-0FB8,U+0FBE-0FDA
+
+=> gives 174 codepoints, 1322 glyphs, 385KB size, GSUB LookupCount 892
+
+-ka, -ga, -ja, -ta, -da, -na, -pa, -ba, -ma, -ya, -ra, -la, -wa, -tsa, -ha
+
+Bhutanese/Tibetan only:
+
+ --unicodes=U+0F00-0F8F,U+0F90,U+0F92,U+0F97,U+0F9F,u+0FA1,U+0FA3,U+0FA4,U+0FA6,U+0FA8,U+0FA9,U+0FAD,U+0FB1-0FB3,U+0FB7
+
+155 codepoints, 1435 glyphs, 426 KB,
+
+ --unicodes=U+0F00-0F8C,U+0F90,U+0F92,U+0F97,U+0F9F,u+0FA1,U+0FA3,U+0FA4,U+0FA6,U+0FA8,U+0FA9,U+0FAD,U+0FB1-0FB3,U+0FB8,U+0FBE-0FDA
+
+180 codepoints, 1456 glyphs, 431KB, GSUB 988 lookup ==> Not working
+
+ --unicodes=U+0F00-0F8C,U+0F90,U+0F92,U+0F94,U+0FF99,U+0FAD,U+0FB1-0FB3,U+0FBA-0FDA
+
+175 codepoints, 1023 glyphs, 285KB, GSUB 646 lookup ==> WORKS WITH EastAsia.ttf and SouthAsia.ttf!
+
+  --unicodes=U+0F00-0F8C,U+0F90,U+0F92,U+0F94,U+0F9F,U+0FF99,U+0FAD,U+0FB1-0FB3,U+0FBA-0FDA
+(added TA) 176 codepoints, 1096 glyphs, 309KB, GSUB 703
+
+ --unicodes=U+0F00-0F8C,U+0F90,U+0F92,U+0F94,U+0F99,U+0F9F,U+0FA4,U+0FAD,U+0FB1-0FB3,U+0FBA-0FDA
+(added TA, PA) 178 codepoints, 1170 glyphs, 330KB, GSUB 749
+
+ --unicodes=U+0F00-0F8C,U+0F90,U+0F92,U+0F94,U+0F99,U+0F9F,U+0FA4,U+0FA9,U+0FAD,U+0FB1-0FB3,U+0FBA-0FDA
+(added TA, PA, TSA) 179 codepoints, 1204 glyphs, 343KB, GSUB 771 ==> WORKS!
+-->

generate.py

@@ -179,26 +179,6 @@ def download_fonts(directory="./"):
             print("Could not retrieve %s. Please check if it exists", ttf)
         sleep(0.5)
 
-def edit_font_info(fontname):
-    from fontTools import ttLib
-    import re
-    print("editing font info %s" % fontname)
-    name_without_spaces = fontname.split('.')[0]
-    name_with_spaces = ' '.join(re.split('(?=[A-Z])', name_without_spaces)).strip()
-    font = ttLib.TTFont(fontname)
-    names = font['name'].names
-    for i in range(len(names)):
-        print(i, names[i].toStr())
-
-    encoding = names[0].getEncoding()
-    names[0].string += "; Copyright 2021 Satish B.; SIL Open Font License v1.1".encode(encoding)
-    names[1].string = name_with_spaces.encode(encoding)
-    names[3].string = names[3].toStr().replace('NotoSans', name_without_spaces).encode(encoding)
-    names[4].string = (name_with_spaces + ' ' + names[2].toStr()).encode(encoding)
-    names[6].string = (name_without_spaces + '-' + names[2].toStr()).encode(encoding)
-    font.save(fontname)
-    font.close()
-
 # append new entries from # https://docs.microsoft.com/en-gb/typography/opentype/spec/scripttags
 merge_noto.SCRIPT_TO_OPENTYPE_SCRIPT_TAG['TaiLe'] = 'tale'
 merge_noto.SCRIPT_TO_OPENTYPE_SCRIPT_TAG['Multani'] = 'mult'

run.sh

@@ -29,13 +29,27 @@ subset_tibetan() {
         fi
         echo "Creating a smaller subset of Tibetan glyphs..."
         $VIRTUAL_ENV/bin/pyftsubset NotoSerifTibetan-Regular.ttf --output-file=NotoSerifTibetanSubset-Regular.ttf \
-                   --unicodes=U+0F00-0F8C,U+0F90,U+0F92,U+0F94,U+0FF99,U+0FAD,U+0FB1-0FB3,U+0FBA-0FDA
+                  --unicodes=U+0F00-0F8C,U+0F90,U+0F92,U+0F94,U+0F99,U+0F9F,U+0FA4,U+0FA9,U+0FAD,U+0FB1-0FB3,U+0FBA-0FDA
     fi
     cd "$OLDPWD"
 }
 
 subset_tibetan
 
+edit_font_info() {
+    local fontname="$1"
+    local without_spaces="${fontname%%.*}"
+    local with_spaces=$(echo "$without_spaces" | sed -E 's/([a-z])([A-Z])/\1 \2/g')
+    local xml_file="$without_spaces".ttx
+    echo "Editing font metadata for $fontname"
+    $VIRTUAL_ENV/bin/ttx -o "$xml_file" "$fontname" 2> /dev/null
+    [[ $? -ne 0 ]] && echo "ERROR: Could not dump $fontname to xml" && return 1
+    sed -i -e "s/Noto Sans/$with_spaces/g" -e "s/NotoSans/$without_spaces/g" "$xml_file"
+    $VIRTUAL_ENV/bin/ttx -o "$fontname" "$xml_file" 2> /dev/null
+    [[ $? -ne 0 ]] && echo "ERROR: Could not dump xml to $fontname" && return 2
+    rm -f "$xml_file"
+}
+
 declare -a fonts=(
     GoNotoSouthAsia.ttf
     GoNotoAsiaHistorical.ttf
@@ -53,4 +67,5 @@ for font in "${fonts[@]}"; do
     printf "Generating font $font. Current time: $(date)\n"
     mkdir -p cached_fonts
     time PYTHONPATH="nototools/nototools" python3 generate.py -o "$font" -d cached_fonts
+    edit_font_info "$font"
 done