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Re: Hanging Punctuation Questions

From: John Hudson <john@tiro.ca>
Date: Mon, 5 Mar 2018 10:54:00 -0800
To: www-style list <www-style@w3.org>
Message-ID: <c4dc4c9c-0dc1-f208-99c5-d55221f5d0c0@tiro.ca>
On 05032018 12:28 AM, fantasai wrote:
>>> (4) How to handle kerning, e.g., for hanging-punctuation:first,
>>> if I hang an opening quote mark, the next letter may also be offset
>>> to the left, since it pushes into the quotation mark. Should kerning
>>> simply be turned off when you hang punctuation between the hung
>>> punctuation and the following glyph?
>>
>> My guess is you subtract the amount of kerning from the amount of hang
>> so the character adjacent to the hanging one is aligned according to
>> its side bearing. However, we should probably check with people who
>> know better. :)
>
> FWIW, CSSWG discussed this in
> https://lists.w3.org/Archives/Public/www-style/2016Oct/0115.html
> and concluded that it didn't know for sure what to do, so the interaction
> of kerning and hanging-punctuation is now marked as undefined.
> https://drafts.csswg.org/css-text-3/#hanging-punctuation-property
>
> If anyone has further insights on this, let us know, maybe we'll define
> it in Level 4. :)


Since the purpose of hanging punctuation is optical alignment of text 
block edges — in which the intrusion of white space from the margin 
around punctuation is has greater visual impact than the intrusion of 
punctuation into the margin —, I would say David is right that the best 
solution is to subtract the kern distance from the distance that the 
punctuation hangs in the margin (or add, in the case of a positive kern 
value). The goal is to get the preceding letter to align with the 
letters above and below on the margin edge.

There are complications, of course. Sequences of multiple punctuation 
signs — e.g. ," — or wider punctuation signs — e.g. …— shouldn't 
completely hang, because there comes a point at which intrusion into the 
margin becomes more distracting. So hanging punctuation needs a maximum 
distance, and to further complicate things this distance might not be 
the same at all text sizes (as a general rule, the smaller the type, the 
more generous the relative hang distance can be).

JH




-- 

John Hudson
Tiro Typeworks Ltd    www.tiro.com
Salish Sea, BC        tiro@tiro.com

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Received on Monday, 5 March 2018 18:54:28 UTC

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