ISSUE-2334: Last Call Comment: filter primitive subregion and feGaussianBlur, feTile and infinite filter input images

Last Call Comment: filter primitive subregion and feGaussianBlur, feTile and infinite filter input images

State:
RAISED
Product:
SVG 1.1 F2 Last Call
Raised by:
Erik Dahlström
Opened on:
2010-06-23
Description:
It seems unclear what the effect of the filter primitive subregion is on
feGaussianBlur (and other kernel-based primitives such as
feConvolutionMatrix). The 1.1 spec says
> All filter primitives have attributes *x*, *y*, *width* and *height* which
identify a subregion which restricts calculation and rendering of the given
filter primitive.

"Restricts calculation" is a bit ambiguous. Does this mean:
-- The implementation takes a snapshot of the input image, with the geometry
of the snapshot determined by the filter primitive subregion for the
feGaussianBlur, and performs processing on that, treating the boundaries of
the snapshot as the boundary where boundary conditions are applied.
or something else?

BTW the spec also says
> If the input has infinite extent and is a tile, the filter is evaluated
with periodic boundary conditions.

I'm not sure what it means for the input to have infinite extent in this
context, and I'm not sure what it means to be "a tile". Does it mean that
the input is an feTile? Could this be more precisely defined?

Original mail:
http://www.w3.org/mid/AANLkTingLaPxHAuQQsNZI2L-EUnwtaHtAgkqulWIRkzs@mail.gmail.com
http://lists.w3.org/Archives/Public/www-svg/2008May/0013.html
Related Actions Items:
Related emails:
  1. SVG/profiles/1.1F2/DoC disco.xsl,1.4,1.5 dump.html,1.3,1.4 (from cvsmail@w3.org on 2011-05-04)
  2. minutes, SVG WG Auckland F2F, day 1 (from cam@mcc.id.au on 2011-02-28)
  3. Re: filter primitive subregion and feGaussianBlur (from robert@ocallahan.org on 2011-01-29)
  4. Re: filter primitive subregion and feGaussianBlur (from ed@opera.com on 2011-01-28)
  5. SVG/profiles/1.1F2/master filters.html,1.42,1.43 (from cvsmail@w3.org on 2011-01-26)
  6. Re: {minutes} 9 December 2010 SVG WG telcon (from chris@w3.org on 2010-12-10)
  7. SVG/profiles/1.1F2/master filters.html,1.38,1.39 (from cvsmail@w3.org on 2010-12-09)
  8. status update (from cam@mcc.id.au on 2010-11-25)
  9. Agenda Nov 18 2010 SVG WG telcon (from ed@opera.com on 2010-11-17)
  10. Re: Review of filter tests. (from ed@opera.com on 2010-10-12)
  11. Minutes Paris F2F day 1 (September 3, 2010) (from anthony.grasso@cisra.canon.com.au on 2010-09-04)
  12. SVG/profiles/1.1F2/DoC getxml.html,NONE,1.1 disco.xsl,1.3,1.4 dump.html,1.2,1.3 dump.xml,1.1,NONE (from cvsmail@w3.org on 2010-08-02)
  13. SVG/profiles/1.1F2/DoC disco.xsl,1.2,1.3 dump.html,1.1,1.2 (from cvsmail@w3.org on 2010-07-29)
  14. Re: ISSUE-2334 - filter primitive subregion and feGaussianBlur (Was: Re: Announcement: Last Call WD of SVG 1.1 Second Edition) (from robert@ocallahan.org on 2010-07-09)
  15. Re: ISSUE-2334 - filter primitive subregion and feGaussianBlur (Was: Re: Announcement: Last Call WD of SVG 1.1 Second Edition) (from th.v.d.gronde@hccnet.nl on 2010-07-08)
  16. Minutes July 6 2010 SVG WG telcon (from anthony.grasso@cisra.canon.com.au on 2010-07-07)
  17. ISSUE-2334 - filter primitive subregion and feGaussianBlur (Was: Re: Announcement: Last Call WD of SVG 1.1 Second Edition) (from ed@opera.com on 2010-07-06)
  18. SVG/profiles/1.1F2/ua-tests gaussianblur-filter-subregion-issue-2334.svg,NONE,1.1 (from cvsmail@w3.org on 2010-07-06)
  19. Minutes June 29 2010 SVGWG telcon (from anthony.grasso@cisra.canon.com.au on 2010-06-30)
  20. Re: Announcement: Last Call WD of SVG 1.1 Second Edition (from robert@ocallahan.org on 2010-06-23)
  21. Re: Announcement: Last Call WD of SVG 1.1 Second Edition (from ed@opera.com on 2010-06-23)
  22. ISSUE-2334: filter primitive subregion and feGaussianBlur, feTile and infinite filter input images [SVG 1.1 F2 Last Call] (from sysbot+tracker@w3.org on 2010-06-23)

Related notes:

The last part of the comment about tiles is addressed in http://dev.w3.org/cvsweb/SVG/profiles/1.1F2/master/filters.html.diff?r1=1.38&r2=1.39&f=h.

New text: [[ If the input has infinite extent and is constant (e.g FillPaint where the fill is a solid color), this operation has no effect. If the input has infinite extent and the filter result is the input to an 'feTile', the filter is evaluated with periodic boundary conditions. ]]

Erik Dahlström, 13 Jan 2011, 19:41:00

RESOLUTION: Clarify 'tile' and what it means for the filter input to have infinite extent in this context. Clarify legacy behaviour for subregion clipping as agreed in http://lists.w3.org/Archives/Public/www-svg/2010Jul/0009.html.

Erik Dahlström, 13 Jan 2011, 20:49:15

http://www.w3.org/2011/02/27-svg-irc#T20-53-07

Erik Dahlström, 27 Feb 2011, 20:54:06

COMMENTER-RESPONSE: Accept

Erik Dahlström, 27 Feb 2011, 20:54:11

ACTION: Accept

Erik Dahlström, 27 Feb 2011, 20:54:36

CHANGE-TYPE: Editorial

Erik Dahlström, 27 Feb 2011, 20:55:23

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