Re: [css-text] Amending hanging-punctuation for Western typography

On 06/04/16 17:34, fantasai wrote:

> I think you didn't understand what I meant... I meant pairs kerning,
> which would be able to handle this perfectly. You just have one of
> the possible "glyphs" in the pair be SOL or EOL. 

See previous comment on existing OpenType GPOS features for optical 
margin alignment.

The model you suggest is similar to an idea that Adobe put forward in 
the early days of OpenType, which is to have invisible topographical 
glyphs inserted by the layout engine at the beginning and ends of lines 
and potentially other places in text block or page layout, e.g beginning 
and end of paragraph. These glyphs would then be addressable in GSUB and 
GPOS lookups to obtain topographically contextual behaviour. It's an 
idea I quite like, but it isn't the model that OpenType went with. 
OpenType instead assigns such behaviour to features, and relies on 
layout engines to apply those features to glyphs based on their 
position. Hence the left and right bounds GPOS features, which are 
applied as single glyph width/position adjustments, not as pair kerning.

BTW, note that in glyph space it is essential to think in terms of left 
and right bounds, not SOL or EOL. Depending on text direction at the 
line break, the starting or ending bound of a glyph might be either left 
or right.


JH

-- 

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

Getting Spiekermann to not like Helvetica is like training
a cat to stay out of water. But I'm impressed that people
know who to ask when they want to ask someone to not like
Helvetica. That's progress. -- David Berlow

Received on Thursday, 7 April 2016 17:55:09 UTC