OverStrike control character

Peter Constable pgcon6 at msn.com
Tue Jun 16 18:01:18 CDT 2020

From: Unicode <unicode-bounces at unicode.org> On Behalf Of Harriet Riddle via Unicode
Sent: Tuesday, June 16, 2020 1:43 PM

>Because with how things usually work currently (in something like Roman or Greek, at any rate), the text renderer will make space for the first character first, and then position any following combining diacritics in that space.

Well, maybe some legacy rendering engines are like that. But that is not how any text rendering engine capable of supporting any significant portion of Unicode is going to work. For most scripts-and for Latin or Greek script with any support for typographic features-the engine needs to resolve what are all the glyph IDs in a run before it can start determining advance widths / positioning. And to do the latter, it will start with default advance widths and positions for all the glyphs but then apply position actions that could revise any advance width or position.


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