- From: Sean Hayes <Sean.Hayes@microsoft.com>
- Date: Thu, 6 May 2010 22:01:25 +0000
- To: Philippe Le Hegaret <plh@w3.org>, Geoff Freed <geoff_freed@wgbh.org>
- CC: HTML WG <public-html@w3.org>
When TTML was being defined, XSL:FO was ahead. And a lot of the CSS3 work was either in a very rough state or not there at all. When CSS3 gets a little more mature, in say 10 years. Then TTML could migrate to it. But to be clear, TTML is *defined* in terms of the semantics of XSL:FO, which is *defined* largely in terms of CSS; but it is its own thing, and it does not require either a full XSL:FO processor or a CSS one. We deliberately did not define an applicative model for styling in TTML, although we discussed it for a long time. Neither did we include either full CSS or XSL:FO in order to keep implementation cost down. -----Original Message----- From: public-html-request@w3.org [mailto:public-html-request@w3.org] On Behalf Of Philippe Le Hegaret Sent: Thursday, May 06, 2010 7:24 PM To: Geoff Freed Cc: HTML WG Subject: Re: Timed tracks On Thu, 2010-05-06 at 13:49 -0400, Geoff Freed wrote: > But since XSL:FO is based on CSS, would it be such a large > amount of work to define mappings of the former to the > latter? In the TTML spec, links are provided to the XSL:FO > elements, which themselves are linked to the appropriate CSS > references. There are differences between XSL FO and CSS. Several values provided in the XSL FO aren't supported in the CSS specifications and are thus impossible to map into a HTML+CSS engine, like in text-decoration. In addition, the innovation happening in CSS isn't happening in the XSL FO world as far as I know and XSL FO is no where to have the same numbers of properties that one can find in CSS. For example, you can't use text-shadow, advanced box model, border-radius, transition effects, or media queries in TTML. There is no support for selectors or @font-face either. Philippe
Received on Thursday, 6 May 2010 22:01:53 UTC