ISSUE-286: Extend the background area behind rendered text to improve readability

rowPadding

Extend the background area behind rendered text to improve readability

State:
PENDING REVIEW
Product:
TTML2
Raised by:
Nigel Megitt
Opened on:
2013-10-23
Description:
The current rendering rules for TTML allow for a background colour to be specified, to be painted behind rendered text. However the edges of this background area are coincident with the foreground text boundary, or with the entire region, neither of which meets all use cases. A common practice in rendering subtitles against video is to extend slightly the background area painted behind the foreground text, e.g. by the width of one space character [1].

[1] https://industry.youview.com/resources/YouView_Core_Technical_Specification_1.0.pdf section 4.4.4.4

No proposed solution is available to address the general case of this, which has some complexity e.g. what to do if a <span> has a different background colour from its parent <p> and the text in the span is wrapped over a line. However the specific use case can be addressed either by specifying a generic rendering rule to cover all text in a region or even a document, e.g. a tts:rowPadding attribute with a length value. Alternative proposals for indicating the requirement for presentation processors to use this rendering behaviour are welcomed!
Related Actions Items:
No related actions
Related emails:
  1. {agenda} TTWG Meeting 2014-12-18 (from nigel.megitt@bbc.co.uk on 2014-12-17)
  2. RE: {minutes} TTWG Meeting 2014-12-04 (from John.Birch@screensystems.tv on 2014-12-04)
  3. Re: {minutes} TTWG Meeting 2014-12-04 (from glenn@skynav.com on 2014-12-04)
  4. {minutes} TTWG Meeting 2014-12-04 (from nigel.megitt@bbc.co.uk on 2014-12-04)
  5. {agenda} TTWG Meeting 2014-12-04 (from nigel.megitt@bbc.co.uk on 2014-12-03)
  6. CORRECTION to {minutes} TTWG Meeting 28/10/2014 (from nigel.megitt@bbc.co.uk on 2014-11-21)
  7. RE: {minutes} TTWG Meeting 27/10/2014 (from nigel.megitt@bbc.co.uk on 2014-10-29)
  8. {agenda} TTWG Meeting 25/9/2014 (from nigel.megitt@bbc.co.uk on 2014-09-24)
  9. Re: {agenda} TTWG Meeting 11/9/2014 (from glenn@skynav.com on 2014-09-10)
  10. {agenda} TTWG Meeting 11/9/2014 (from nigel.megitt@bbc.co.uk on 2014-09-10)
  11. {agenda} TTWG Meeting 4/9/2014 (from nigel.megitt@bbc.co.uk on 2014-09-03)
  12. {agenda} TTWG Meeting 31/7/2014 (from nigel.megitt@bbc.co.uk on 2014-07-30)
  13. {agenda} TTWG Meeting 24/7/2014 (from nigel.megitt@bbc.co.uk on 2014-07-23)
  14. {agenda} TTWG Meeting 17/7/2014 (from nigel.megitt@bbc.co.uk on 2014-07-16)
  15. {agenda} TTWG Meeting 10/7/2014 (from nigel.megitt@bbc.co.uk on 2014-07-09)
  16. RE: {agenda} TTWG Meeting 19/6/2014 (from mdolan@newtbt.com on 2014-06-18)
  17. {agenda} TTWG Meeting 19/6/2014 (from nigel.megitt@bbc.co.uk on 2014-06-18)
  18. RE: {agenda} TTWG Meeting 12/6/2014 (from mdolan@newtbt.com on 2014-06-12)
  19. Re: {agenda} TTWG Meeting 12/6/2014 (from pal@sandflow.com on 2014-06-11)
  20. Re: {agenda} TTWG Meeting 12/6/2014 (from nigel.megitt@bbc.co.uk on 2014-06-11)
  21. Re: {agenda} TTWG Meeting 12/6/2014 (from pal@sandflow.com on 2014-06-11)
  22. Re: {agenda} TTWG Meeting 12/6/2014 (from nigel.megitt@bbc.co.uk on 2014-06-11)
  23. {agenda} TTWG Meeting 12/6/2014 (from nigel.megitt@bbc.co.uk on 2014-06-11)
  24. RE: {agenda} TTWG Meeting 5/6/2014 (from mdolan@newtbt.com on 2014-06-04)
  25. {agenda} TTWG Meeting 5/6/2014 (from nigel.megitt@bbc.co.uk on 2014-06-04)
  26. {agenda} TTWG Meeting 29/5/2014 (from nigel.megitt@bbc.co.uk on 2014-05-28)
  27. {agenda} TTWG Meeting 22/5/2014 (from nigel.megitt@bbc.co.uk on 2014-05-21)
  28. {agenda} TTWG Meeting 15/5/2014 (from nigel.megitt@bbc.co.uk on 2014-05-14)
  29. Re: {agenda} TTWG Meeting 8/5/2014 (from tmichel@w3.org on 2014-05-08)
  30. {agenda} TTWG Meeting 8/5/2014 (from nigel.megitt@bbc.co.uk on 2014-05-07)
  31. {minutes} TTWG Meeting 1/5/2014 (from nigel.megitt@bbc.co.uk on 2014-05-01)
  32. {agenda} TTWG Meeting 1/5/2014 (from nigel.megitt@bbc.co.uk on 2014-04-30)
  33. {agenda} TTWG Meeting 24/4/2014 (from nigel.megitt@bbc.co.uk on 2014-04-23)
  34. {agenda} TTWG Meeting 17/4/2014 (from nigel.megitt@bbc.co.uk on 2014-04-17)
  35. {minutes} TTWG Meeting 27/3/2014 (from nigel.megitt@bbc.co.uk on 2014-03-27)
  36. Re: {agenda} TTWG Meeting 27/3/2014 (from glenn@skynav.com on 2014-03-27)
  37. Re: {agenda} TTWG Meeting 27/3/2014 (from tmichel@w3.org on 2014-03-27)
  38. {agenda} TTWG Meeting 27/3/2014 (from nigel.megitt@bbc.co.uk on 2014-03-26)
  39. {minutes} TTWG Meeting 20/3/2014 (from nigel.megitt@bbc.co.uk on 2014-03-20)
  40. Re: {agenda} TTWG Meeting 20/3/2014 (from glenn@skynav.com on 2014-03-19)
  41. {agenda} TTWG Meeting 20/3/2014 (from nigel.megitt@bbc.co.uk on 2014-03-19)
  42. {agenda} TTWG Meeting 27/2/2014 (from nigel.megitt@bbc.co.uk on 2014-02-26)
  43. {agenda} TTWG Meeting 20/2/2014 (from nigel.megitt@bbc.co.uk on 2014-02-19)
  44. {agenda} TTWG Meeting 13/2/2014 (from nigel.megitt@bbc.co.uk on 2014-02-12)
  45. Re: {agenda} TTWG Meeting 6/2/2014 (from silviapfeiffer1@gmail.com on 2014-02-06)
  46. Re: {agenda} TTWG Meeting 6/2/2014 (from silviapfeiffer1@gmail.com on 2014-02-06)
  47. Re: {agenda} TTWG Meeting 6/2/2014 (from singer@apple.com on 2014-02-05)
  48. {agenda} TTWG Meeting 6/2/2014 (from nigel.megitt@bbc.co.uk on 2014-02-05)
  49. {agenda} TTWG Meeting 30/01/2014 (from nigel.megitt@bbc.co.uk on 2014-01-30)
  50. {agenda} 16/1/14 TTWG meeting (from nigel.megitt@bbc.co.uk on 2014-01-16)
  51. {minutes} 9/1/14 TTWG Meeting (from nigel.megitt@bbc.co.uk on 2014-01-09)
  52. TTWG Agenda for 9/1/14 (from nigel.megitt@bbc.co.uk on 2014-01-08)
  53. Re: Issue-286 padding (from glenn@skynav.com on 2013-12-19)
  54. Re: Issue-286 padding (from glenn@skynav.com on 2013-12-19)
  55. Re: Issue-286 padding (from nigel.megitt@bbc.co.uk on 2013-12-19)
  56. Re: Issue-286 padding (from innovimax+w3c@gmail.com on 2013-12-19)
  57. Re: Issue-286 padding (from nigel.megitt@bbc.co.uk on 2013-12-19)
  58. Re: Issue-286 padding (from innovimax+w3c@gmail.com on 2013-12-19)
  59. Re: Issue-286 padding (from nigel.megitt@bbc.co.uk on 2013-12-19)
  60. Re: Issue-286: application of padding to p etc (from glenn@skynav.com on 2013-12-19)
  61. New feature requests - working group process (from nigel.megitt@bbc.co.uk on 2013-12-12)
  62. Re: Issue-286: application of padding to p etc (from nigel.megitt@bbc.co.uk on 2013-12-12)
  63. Re: Issue-286: application of padding to p etc (from glenn@skynav.com on 2013-12-12)
  64. TTWG Agenda for 12/12/13 (from nigel.megitt@bbc.co.uk on 2013-12-11)
  65. Re: Issue-286: application of padding to p etc (from nigel.megitt@bbc.co.uk on 2013-12-11)
  66. Re: Issue-286: application of padding to p etc (from glenn@skynav.com on 2013-12-11)
  67. Re: Issue-286: application of padding to p etc (from nigel.megitt@bbc.co.uk on 2013-12-11)
  68. Re: TTWG Agenda for 5/12/13 (from nigel.megitt@bbc.co.uk on 2013-12-11)
  69. Re: TTWG Agenda for 5/12/13 (from glenn@skynav.com on 2013-12-11)
  70. RE: TTWG Agenda for 5/12/13 (from mdolan@newtbt.com on 2013-12-10)
  71. Re: Issue-286: application of padding to p etc (from glenn@skynav.com on 2013-12-10)
  72. Re: Issue-286: application of padding to p etc (from tai@irt.de on 2013-12-09)
  73. Re: Issue-286: application of padding to p etc (from nigel.megitt@bbc.co.uk on 2013-12-09)
  74. RE: Issue-286: application of padding to p etc (from John.Birch@screensystems.tv on 2013-12-09)
  75. Re: Issue-286: application of padding to p etc (from glenn@skynav.com on 2013-12-07)
  76. Re: Issue-286: application of padding to p etc (from nigel.megitt@bbc.co.uk on 2013-12-06)
  77. Re: Issue-286: application of padding to p etc (from glenn@skynav.com on 2013-12-06)
  78. Re: Issue-286: application of padding to p etc (from John.Birch@screensystems.tv on 2013-12-05)
  79. Issue-286: application of padding to p etc (from nigel.megitt@bbc.co.uk on 2013-12-05)
  80. TTWG Minutes for 5/12/13 (from nigel.megitt@bbc.co.uk on 2013-12-05)
  81. Re: Issue-286 padding (from nigel.megitt@bbc.co.uk on 2013-12-05)
  82. TTWG Agenda for 5/12/13 (from nigel.megitt@bbc.co.uk on 2013-12-04)
  83. Issue-286 padding (from nigel.megitt@bbc.co.uk on 2013-12-04)
  84. TTML Minutes for 15/11/13 (from nigel.megitt@bbc.co.uk on 2013-11-21)
  85. TTML Minutes for 11/11/13 (from nigel.megitt@bbc.co.uk on 2013-11-21)
  86. Re: TTML Agenda for 21/11/13 (from cyril.concolato@telecom-paristech.fr on 2013-11-21)
  87. Re: TTML Agenda for 21/11/13 (from glenn@skynav.com on 2013-11-21)
  88. Re: TTML Agenda for 21/11/13 (from tmichel@w3.org on 2013-11-21)
  89. TTML Agenda for 21/11/13 (from nigel.megitt@bbc.co.uk on 2013-11-20)
  90. Issue-286 rowPadding images (from nigel.megitt@bbc.co.uk on 2013-11-07)
  91. RE: TTML Agenda for 31/10/13 (from Sean.Hayes@microsoft.com on 2013-10-31)
  92. TTML Agenda for 31/10/13 (from nigel.megitt@bbc.co.uk on 2013-10-30)
  93. {minutes} TTML Meeting of 24/10/13 (from glenn@skynav.com on 2013-10-24)
  94. RE: TTML Agenda for 24/10/13 (from mdolan@newtbt.com on 2013-10-23)
  95. TTML Agenda for 24/10/13 (from nigel.megitt@bbc.co.uk on 2013-10-23)
  96. ISSUE-286 (rowPadding): Extend the background area behind rendered text to improve readability [TTML2] (from sysbot+tracker@w3.org on 2013-10-23)

Related notes:

Nigel: P1
Glenn: having some images would help to understand

Philippe Le Hégaret, 24 Oct 2013, 15:52:55

Owner is Andreas + Nigel

Nigel Megitt, 28 Oct 2013, 11:57:49

[pal]: CSS folks mentioned box-decoration-break as a possibiliy

11 Nov 2013, 06:25:47

Examples, proposed syntax and mapping to HTML/CSS now added to https://www.w3.org/wiki/TTML/changeProposal015#box-decoration-break

Nigel Megitt, 19 Mar 2014, 13:32:02

[nigel]: (TTWG F2F today) We will support the EBU line padding proposal with the combination of padding on inline content elements and box-decoration-break.

28 Oct 2014, 20:30:58

Addressed [1] by defining that padding on span is cloned at line break boundaries.

[1] https://dvcs.w3.org/hg/ttml/rev/38897327d190

Glenn Adams, 1 Dec 2014, 02:31:03

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David Singer <singer@apple.com>, Nigel Megitt <nigel.megitt@bbc.co.uk>, Chairs, Thierry Michel <tmichel@w3.org>, Philippe Le Hégaret <plh@w3.org>, Staff Contacts
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