Re: [compositing] 'isolation' and <img>

On Fri, Mar 8, 2013 at 3:02 PM, L. David Baron <dbaron@dbaron.org> wrote:

> https://dvcs.w3.org/hg/FXTF/rawfile/tip/compositing/index.html#isolation
> currently says:
>
>   # In CSS, the ‘isolation’ property of an <img> or a background image
>   # must always be ‘isolate’. For instance, if you link to an SVG file
>   # through the ‘img’ tag, the content of that SVG will not blend with
>   # its backdrop.
>
> This is an incorrect description of what you're trying to describe,
> and implementing it would break existing content.
>

could you tell me what content would be broken?
'isolation' should only have an effect when there's blending.


>
> For example:
>
>   <img style="background: rgba(0, 255, 0, 0.5)"
>        src="image-with-transparent-regions.png" />
>
> has the background-color of the img element (to which the
> 'isolation' property applies) blend with the backdrop of the image.
>
> Instead, you should say something about the isolation of the
> rendering of sub-documents referenced through elements such as
> <img>, <object>, and <iframe>.
>
> However, I'm not even sure that they should always be isolated.
>
> -David
>
> --
> 𝄞   L. David Baron                         http://dbaron.org/   𝄂
> 𝄢   Mozilla                           http://www.mozilla.org/   𝄂
>
>