I have been looking at various kerning in Arabic fonts, and I have noticed that pairs between letter/punctuation or numeral/punctuation are very uncommon. Neo Sans Arabic seems to be one of very few exceptions that do have such pairs. Is there a good reason not to do it, or a reason why it hasn't been the case in the past (e.g. it's been hard to do)?
I can't help but want to test and kern pairs like these, for example:
ء؟ ا؟ أ؟ إ؟ آ؟ ٱ؟ ب؟ پ؟ ت؟ ث؟ ٹ؟ ج؟ چ؟ ح؟ خ؟
د؟ ذ؟ ڈ؟ ر؟ ز؟ ڑ؟ ژ؟ س؟ ش؟ ص؟ ض؟ ط؟ ظ؟ ع؟ غ؟
ف؟ ڤ؟ ق؟ ك؟ ک؟ گ؟ ل؟ م؟ ن؟ ه؟ ؟ ہ؟ ۂ؟ ھ؟ ة؟
و؟ ؤ؟ ى؟ ي؟ ئ؟ ی؟ ے؟ ۓ؟ ـے؟ ـۓ؟ ە؟ لا؟ لأ؟ لإ؟ لآ؟
”ء“ ”ا“ ”أ“ ”إ“ ”آ“ ”ٱ“ ”ب“ ”پ“ ”ت“ ”ث“ ”ٹ“ ”ج“ ”چ“ ”ح“ ”خ“
”د“ ”ذ“ ”ڈ“ ”ر“ ”ز“ ”ڑ“ ”ژ“ ”س“ ”ش“ ”ص“ ”ض“ ”ط“ ”ظ“ ”ع“ ”غ“
”ف“ ”ڤ“ ”ق“ ”ك“ ”ک“ ”گ“ ”ل“ ”م“ ”ن“ ”ه“ ”ہ“ ”ۂ“ ”ھ“ ”ة“
”و“ ”ؤ“ ”ى“ ”ي“ ”ئ“ ”ی“ ”ے“ ”ۓ“ ـے“ ـۓ“ ”ە“ ”لا“ ”لأ“ ”لإ“ ”لآ“
٫٠٫١٫٢٫٣٫٤٫٥٫٦٫٧٫٨٫٩٫۰٫۱٫۲٫۳٫۴٫۵٫۶٫۷٫۸٫۹٫
٬٠٬١٬٢٬٣٬٤٬٥٬٦٬٧٬٨٬٩٬۰٬۱٬۲٬۳٬۴٬۵٬۶٬۷٬۸٬۹٬
,٠,١,٢,٣,٤,٥,٦,٧,٨,٩,۰,۱,۲,۳,۴,۵,۶,۷,۸,۹,
.٠.١.٢.٣.٤.٥.٦.٧.٨.٩.۰.۱.۲.۳.۴.۵.۶.۷.۸.۹.
"٠"١"٢"٣"٤"٥"٦"٧"٨"٩"۰"۱"۲"۳"۴"۵"۶"۷"۸"۹"
“٠” “١” “٢” “٣” “٤” “٥” “٦” “٧” “٨” “٩”
?٠?١?٢?٣?٤?٥?٦?٧?٨?٩?۰?۱?۲?۳?۴?۵?۶?۷?۸?۹?
؟٠؟١؟٢؟٣؟٤؟٥؟٦؟٧؟٨؟٩؟۰؟۱؟۲؟۳؟۴؟۵؟۶؟۷؟۸؟۹؟
[edit:] Sorry, wrong category to post. I wanted to delete or move it but apparently I can't.
Comments
What's the difference, in this context, between two letters and a letter followed by a punctuation mark? If there's a RTL/LTR problem, isn't it supposed to affect two letters just as well?
cf. Beyond Shaping
Actually most old Arabic fonts had zero kerning pairs, and the problematic right-joining letters that would need kerning (like ر and و) were kerned metal type-style by having negative left side bearing. After some tinkering with kerning, I ended up adopting the same, with only few contextual positioning rule for really problematic combinations.