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Re: [csswg-drafts] [css-text-decor] text-decoration-thickness & text-underline-position properties

From: John Hudson via GitHub <sysbot+gh@w3.org>
Date: Tue, 22 Nov 2016 19:54:58 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-262347728-1479844497-sysbot+gh@w3.org>
As @litherum notes, the underline position and thickness values in a 
font's post table are liable to be junk data, since many font makers 
simply leave these as tool defaults. They are also font level settings
 that make no account for the possibility of multiple scripts and 
writing systems supported by a font that might require localised 
underline position and thickness.

Obviously, in this situation, it makes sense for CSS to come up with 
some reasonable fallback method to automate underlining, but I still 
think it would be preferable for the font developer to provide good 
and localised data. I've introduced this idea to the ad hoc OpenType 
working group, and will see what kind of traction I can get. Mostly 
likely implementation would be new fields in the BASE table, using 
existing OTL script (and maybe language system) tagging for 
localisation.

Having new data separate from the post table values should encourage 
font developers to provide better data, especially if font tools 
require them to make explicit decisions rather than providing default 
values. That is, this data should only be included in fonts if a 
developer has explicitly defined it; in the absence of this new data, 
CSS should fall back to automated underline position and thickness. 
Make sense?
_____

PS. Everything I've written here regarding underline also applies to 
strikethrough.

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Received on Tuesday, 22 November 2016 19:55:05 UTC

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