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Re: @font-face unicode-range descriptor

From: Martin J. Duerst <duerst@w3.org>
Date: Mon, 31 Jul 2000 17:54:34 +0900
Message-Id: <4.2.0.58.J.20000731175003.02be3940@sh.w3.mag.keio.ac.jp>
To: Shyjan Mahamud <mahamud@marr.ius.cs.cmu.edu>, www-font@w3.org
Hello Shyjan,

you are right that the feature to mask out some part of a font
is very desirable when creating virtual fonts (as you call them),
and that the description in CSS2 doesn't say whether this can
be done with unicode-range or not.

I will forward this request to the relevant Working Groups
within W3C. If you could help check out some implementations,
that would be great.

Regards,    Martin.

At 00/07/30 01:33 -0400, Shyjan Mahamud wrote:
>hello, i am trying to better understand the role of the unicode-range
>descriptor in the @font-face rule. as far as i can tell, this
>descriptor is primarily intended to avoid downloading fonts that don't
>contain glyphs of interest. however there are applications where you
>would want to create "virtual fonts" from a bunch of fonts. the
>example "Excelsior" shown on http://www.w3.org/TR/REC-CSS2/fonts.html
>is close to what i am thinking of, but i need some clarification.
>suppose you are defining a new virtual font "vfont" from two real
>fonts "rfont1" and "rfont2". assume we want the unicode points U+00-FF
>from "rfont1" and U+100-200 from "rfont2".
>adapting the "Excelsior" example to this case, we would have something
>like :
>
>@font-face {
>      font-family: vfont;
>      src: local(rfont1), url(...);
>      unicode-range: U+??; /* Latin-1 */
>}
>@font-face {
>      font-family: vfont;
>      src: local(rfont2), url(...);
>      unicode-range: U+100-200; /* Latin Extended A and B */
>}
>all this is clear. the question is what happens when the real fonts
>rfont1 and rfont2 have overlapping unicode points, say for simplicity
>they both have U+000-200. i would like characters in U+100-200 to be
>picked up from only rfont2 and not rfont1 even though a user agent
>can optimize by using only rfont1 for the whole range. i want to know if this
>semantics is implied by the unicode-range descriptor. it is not
>entirely clear from the CSS2 spec that this is the case since the
>discussion there seems to be more devoted to avoiding having to
>download fonts unnecessarily. in other words i am less interested in
>specifying the actual range that a font contains, but rather i am
>interested in specifying a subset of the actual range.
>
>- shyjan
Received on Monday, 31 July 2000 04:49:41 UTC

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