[MPEG-OTSPEC] AHG Kick-off - new email list, new mandates! IMPORTANT!

[John Hudson]

On 25032020 12:56 pm, Levantovsky, Vladimir via mpeg-otspec wrote:
>
> 1.Lack of font metrics for writing systems other than Western and CJK
>
> Additional discussions are needed, we may need to consult with outside 
> experts who are familiar with typographic environments of different 
> languages and writing systems to consider the additional complexities 
> associated with languages like Thai [where glyphs are often composed 
> with multiple marks positioned above and below the base].
>
There are a couple of components to this:

1) Script- or language-specific versions of common metrics used for 
linespacing.

2) Script-specific data points that define internal relationships (in 
the way, e.g. cap height, x-height, ascender, and descender data points 
define height relationships in European scripts).

There has been a lot of prior discussion in the OTWG on (1), and the 
consensus seems to be that this should be done with a new version of the 
BASE table, using existing OTL script and language system tags with sets 
of vertical metrics for linespacing corresponding to the OS/2 table Typo 
metrics.

(2) has been discussed in various places, but as you say consultation is 
needed to identify the data points that are useful for each script 
(which might not always be obvious: much depends on how the data points 
might be used, e.g. in calculating size and alignment of 'dropcap' 
initials in CSS).

JH


-- 

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

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