- From: Richard Wordingham <richard.wordingham@ntlworld.com>
- Date: Thu, 29 Oct 2015 09:05:09 +0000
- To: "public-i18n-mongolian@w3.org" <public-i18n-mongolian@w3.org>
On Thu, 29 Oct 2015 07:00:07 +0000 Greg Eck <greck@postone.net> wrote: > I may be using it in a non-standard sense, but my use of the term > over-ride is when the standard context of the default glyph does not > render the default glyph but instead another glyph. An example would > be найма (eight) where NAIMA is rendered with no FVS, but > NAI+FVS2+MA is rendered . The FVS2 assignment is needed to get the > default single-shilbe back where the context tells the shaping engine > to render the double-shilbe. Of course, all the shaping engine knows is that some characters have contextual variants. The OpenType engine does not have to understand the specific meaning of the variation selectors, and knows nothing of the default shaping rules - merely their possible existence. The knowledge of what to render lies almost entirely in the font. There are two possible mechanisms: 1. Normal character plus variation selector chooses a different starting glyph, which is then substituted for differently to the glyph chosen without a variation selector. 2. A purely formal glyph is created for the variation selector, and combining rules then apply the intended effect of the variation selector. Richard.
Received on Thursday, 29 October 2015 09:05:41 UTC