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Re: [css-round-display] Suggest 'polar-anchor' property for positioning elements without overflowing

From: Brad Kemper <brad.kemper@gmail.com>
Date: Thu, 15 Oct 2015 23:42:29 -0700
Cc: www-style@w3.org
Message-Id: <7E816CB9-B629-4561-B1CD-FBE35B9B6F68@gmail.com>
To: Jihye Hong <jh.hong@lge.com>

On Oct 15, 2015, at 12:59 AM, Jihye Hong <jh.hong@lge.com> wrote:

>> I think most of the time, having a 2-dimensional polar-anchor seems like
> overkill. Isn't the 
>> real issue that you often (usually?) want 'polar-distance: 100%' to just
> touch the inside edge
>> of the containing block? I would do this (an effect similar to
> 'polar-anchor: auto) by adding 
>> an optional keyword to 'polar-distance' value of either 'outer' or 'center'
> which determined the 
>> anchor point used for 'polar-distance: 100%'. 
>> 'Polar-distance: 100% outer' would mean that an imaginary ellipse that
> touched all four sides of
>> the border box (equivalent to border-radius:100%) would be positioned as
> far out along the 
>> ray as it could without passing the inner edge of the containing block's
> border shape.
> Is my understanding correct about your suggestion like below? :
>    1) polar-distance: 100% outer :
>    Only one point of contact exists between the element and the inner
> edge of the containing block's border shape and the element is positioned
> inside the containing block's border shape.

Mostly, if you are considering the element's point to be on the imaginary eclipse I described. For container blocks with square corners, or inner border radiuses less than that of the positioned element's "imaginary ellipse", then there could be 2 sides contacting the imaginary ellipse, both limiting how far out 100% would be. 

>    2) polar-distance: 100% center :
>    The center point of the element is positioned on the inner edge of
> the containing block's border shape.


> If it's correct, I agree with that having a 2-dimensional polar-anchor isn't
> necessary.
> Thanks to your solution, we will use polar-distance with optional keyword
> value to set the anchor point instead of using polar-anchor. 


> We haven't decided yet which keywords to use for the optional value. 

Sure. There's room for bikeshedding there.

> Of course, 'center' and 'outer' are one the table. : )


>> If even more control is needed, we could have a 'polar-margin' property
> that guaranteed a 
>> distance between the imaginary ellipse and the inner border edge of the
> container.
> I think that 'polar-margin' property and 'polar-padding' property would
> guarantee the overflow problem. I will add those new properties as soon as
> possible.

Received on Friday, 16 October 2015 06:42:57 UTC

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