- From: Bert Bos <bert@w3.org>
- Date: Thu, 17 Jul 2014 15:59:36 +0200
- To: www-style@w3.org
On Wednesday 16 July 2014 17:51:33 Bert Bos wrote:
> The WG decided[1] nevertheless to add that special case, also because it
> is unclear how to interpret 'background-position' for an element with
> 'display: none'.
>
> Simon Sapin was going to propose concrete text, but as I was adding an
> entry to the list of errata, I though I could try to write it myself as
> well. Thus, I propose to add, right after the paragraph in 14.2[2] that
> ends
>
> [...] Such backgrounds must also be anchored at the same point as
> they would be if they were painted only for the root element.
>
> the following two new paragraphs:
>
> # However, if the element whose background would be used for the
> # background of the canvas has 'display: none', or is a descendant
> # of element with 'display: none', then the canvas background is
> # undefined.
> #
> # Note that, if the element has 'visibility: hidden' but not 'display:
> # none', its background _is_ used for the canvas.
After discussion, the WG decided[3] to modify the above (1) to say that the
canvas background is transparent rather than undefined, and (2) to phrase
the condition indirectly, in terms of the existence or not of a box for the
element, rather than a specific value of the 'display' property. The
indirection may avoid another erratum in the future if we ever add other
properties that suppress box generation. (The proposed 'display-box'
property, if accepted, would be one such property.)
With that in mind, here is an updated proposal for the errata. Add, right
after the paragraph in 14.2[2] that ends
[...] Such backgrounds must also be anchored at the same point as
they would be if they were painted only for the root element.
the following two new paragraphs:
# However, if no boxes are generated for the element whose background
# would be used for the background of the canvas, then the canvas
# background is transparent. (in CSS 2.1, that is the case when the
# element or an ancestor has 'display: none'.)
#
# Note that, if the element has 'visibility: hidden' but not 'display:
# none', boxes _are_ generated for it and its background _is_ used for
# the canvas.
> [1] http://lists.w3.org/Archives/Public/www-style/2014Jul/0162.html
> [2] http://www.w3.org/TR/2011/REC-CSS2-20110607/colors.html#background
[3] http://lists.w3.org/Archives/Public/www-style/2014Jul/0299.html
Bert
--
Bert Bos ( W 3 C ) http://www.w3.org/
http://www.w3.org/people/bos W3C/ERCIM
bert@w3.org 2004 Rt des Lucioles / BP 93
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Received on Thursday, 17 July 2014 14:00:10 UTC