ISSUE-210: The values for alpha in rgba() don't correspond to CSS3 Color definitions
rgba() alpha value space
The values for alpha in rgba() don't correspond to CSS3 Color definitions
- State:
- OPEN
- Product:
- TTML2
- Raised by:
- Glenn Adams
- Opened on:
- 2013-05-15
- Description:
- As presently defined, we allow the alpha value in an rgba() tuple to take a value from 0 to 255, rather than 0.0 to 1.0 (or 0% to 100%) as defined in CSS3 Color. On the other hand, we do use the CSS3 Color alpha values of 0.0 to 1.0 for opacity. This creates a bit of an anomaly if we should want to define tts:color in terms of CSS3 Color's definition of 'color'.
I'm presently marking this for TTML1.0, if we want to address in TTML10SE. Otherwise, we should push out to TTML.next. - Related Actions Items:
- No related actions
- Related emails:
- {minutes} TTWG Meeting 2015-02-05 (from nigel.megitt@bbc.co.uk on 2015-02-05)
- {agenda} TTWG Meeting 2015-02-05 (from nigel.megitt@bbc.co.uk on 2015-02-04)
- {agenda} TTWG Meeting 2015-01-29 (from nigel.megitt@bbc.co.uk on 2015-01-28)
- {agenda} TTWG Meeting 2015-01-22 (from nigel.megitt@bbc.co.uk on 2015-01-21)
- {agenda} TTWG Meeting 2015-01-15 (from nigel.megitt@bbc.co.uk on 2015-01-14)
- CORRECTION to {minutes} TTWG Meeting 28/10/2014 (from nigel.megitt@bbc.co.uk on 2014-11-21)
- RE: {minutes} TTWG Meeting 27/10/2014 (from nigel.megitt@bbc.co.uk on 2014-10-29)
- {minutes} TTML Meeting of 24/10/13 (from glenn@skynav.com on 2013-10-24)
- RE: TTML Agenda for 24/10/13 (from mdolan@newtbt.com on 2013-10-23)
- TTML Agenda for 24/10/13 (from nigel.megitt@bbc.co.uk on 2013-10-23)
- RE: ISSUE-210 (rgba() alpha value space): The values for alpha in rgba() don't correspond to CSS3 Color definitions [TTML 1.0] (from Sean.Hayes@microsoft.com on 2013-05-17)
- ISSUE-210 (rgba() alpha value space): The values for alpha in rgba() don't correspond to CSS3 Color definitions [TTML 1.0] (from sysbot+tracker@w3.org on 2013-05-15)
Related notes:
Postpone a resolution for this issue to TTML.next.
Glenn Adams, 27 Jun 2013, 15:48:10Glenn: P2
Philippe Le Hégaret, 24 Oct 2013, 15:34:34Address this in the HTML/CSS mapping section.
Glenn Adams, 14 Sep 2014, 13:40:50Take no action to syntax or semantics of alpha. Simply deal with this in the process of mapping to XSL-FO or HTML/CSS, etc.
Glenn Adams, 14 Jan 2015, 06:21:48[nigel]: [meeting 2015-02-05] Resolution is to add an editorial note to readers highlighting the difference in scale of alpha value.
5 Feb 2015, 15:42:55Display change log