Re: [css-masking] new value for 'mask-clip'

Sounds like a valid use-case to me, but what about naming it
descendent-box ? Isn't that more clear.


On Sat, Oct 20, 2012 at 5:03 AM, Dirk Schulze <> wrote:
> Hi,
> The 'mask-clip' property[1] takes the three boxes defined for 'background-clip'[2]: content-box, padding-box and border-box. This means that the 'mask-image' property will always clip to at least the border box element. Overflowing content will always be clipped to the border box.
> Authors may want masking to take overflowing content into account as well.
> #parent {
>         mask-image: url(image.svg);
>         width: 200px;
>         height: 200px;
> }
> #content {
>         width: 500px;
>         height: 500px;
> }
> <div id="parent">
>         <img id="content" src="image.png" width="500">
> </div>
> Instead of having the image clipped to the border box of the div box, authors may want to have the whole group get masked.
> I would suggest a new keyword 'group-box'. If that keyword is used, the union of border boxes of the current element and all descendant elements get computed and used to specify the clipping area.
> The SVG WG asked for another keyword 'filter-box'. This keyword would use the calculated filter box of an applied 'filter' property. The filter box is the affected (painted) area of an filter. The current specification of Filter Effects[3] does not define such a term yet. It must be described by Filter Effects first.
> Any comments or suggestions?
> Greetings,
> Dirk
> [1]
> [2]
> [3]

Kenneth Rohde Christiansen
Senior Engineer, WebKit, Qt, EFL
Phone  +45 4093 0598 / E-mail kenneth at


Received on Sunday, 21 October 2012 09:21:27 UTC