Re: Letter spacing in Indic scripts

On 06/12/13 9:55 AM, Richard Ishida wrote:

> [1] do indic scripts do letter-spacing?

I think a better way of asking this is 'Does Indic typography do 
letter-spacing'?

In my experience, it is unusual to see much letter-spacing in Indic 
typography -- i.e. tracking applied on top of default font 
spacing/kerning as a feature of typographic design --, but there are 
historical examples of much more widely spaced types for disconnected 
scripts such as Telugu than is common today. If someone wanted to 
emulate such typography, using modern fonts, the letter-spacing property 
would be a sensible way to do so.

There are complications though. Do you letter-space whole clusters or 
also the non-connecting, non-anchored parts of the clusters? If the 
latter, then you are likely to get inconsistent results depending how 
the clusters have been built from the OpenType Layout tables. For 
instance, in the Telugu font I am building at the moment, postscript 
consonant forms are sometimes spacing glyphs kerned to preceding bases 
and sometimes combining glyphs anchored to intervening subscripts, 
contextually determined to affect the best relationships in the cluster. 
This could result in letter-spacing resulting in different results in 
different clusters, because spacing postscripts might be tracked while 
anchored marks should not.

> [2] if they do, what happens for scripts with a bar, such as Devanagari?
> Is the bar continuous or broken?

I would expect the bar to be continuous, but I'm not aware of any 
mechanism that would make that possible interactively with the 
letter-spacing property. The head line height and thickness is not 
explicit anywhere in the font data, and there's nothing like an Arabic 
tatweel that could be inserted.

J.

Received on Friday, 6 December 2013 18:37:25 UTC