Re: review of CSS Masking

Hello Cameron,

Tuesday, March 18, 2014, 3:27:52 PM, you wrote:

> Hi Dirk,

> Here are some review comments on CSS Masking.  I'm focusing mostly on 
> meaningful things, but I've included a couple of comments about wording.

> https://dvcs.w3.org/hg/FXTF/raw-file/061c12d148be/css-masking-1/index.html


> == 1.1 Clipping ==

>> The clip-path property can reference an SVG graphics element or use a
>> specified basic shapes as clipping path.

> I don't think the clip-path property can reference any SVG graphics 
> element.  It's only a <clipPath> element.

Weren't we planning to relax that so that we could point to arbitrary
paths?

> == 1.2 Masking ==

>> Note: While masking gives many possibilities for enhanced graphical
>> effects and in general provides more control over the “visible
>> portions” of the content, clipping paths can perform better and are
>> easier to interpolate.

> It's not clear to me how clipping paths are easier to interpolate.

A pair of paths can be easily interpolated one to the other (animated
clipping path). A pair of raster image masks can't so easily be
interpolated to give an animated mask.

> == 3 Values ==

>> In addition to the property-specific values listed in their
>> definitions, all properties defined in this specification also accept
>> the inherit keyword as their property value. For readability it has
>> not been repeated explicitly.

> Surely also 'initial' and 'unset'.  Maybe there is some more up-to-date
> text you can use here.
(Agreed)


> It might be confusing here that "clipped region" and "clipping region"
> are being used to mean opposite things.  (The first is the part that is
> clipped away and the second is the part that remains after clipping.)

Suggest "clipped-out-region"


> == 7.5 Masking Area: the mask-clip property ==

>> Determines the mask painting area, which determines the area that is
>> affected by the mask. The painted content of an element may be
>> restricted to this area.

> What does it mean by "may be restricted to this area"?  I assume you 
> don't mean "MAY".  Is this just the area that the mask affects, and 
> outside that area, the element is painted unmasked?

Agree that MAY is wrong here. Suggest "Outside this area, the painted
content of an element is unaffected by the mask. It is not clipped at
the boundary of the mask".

That gives two testable assertions while the previous text was
untestable as well as being unclear.


>> The mask shorthand also resets mask-box to its initial value.

> mask-box is a shorthand, and shorthands don't have initial values.  You
> should list the specific longhands that get reset.
Yes.



-- 
Best regards,
 Chris                            mailto:chris@w3.org

Received on Tuesday, 18 March 2014 14:58:42 UTC