Re: [CSSWG] Minutes and Resolutions Tokyo F2F Fri: CSS2.1, box-shadow and border-image

On Mar 9, 2009, at 1:37 AM, fantasai wrote:

> Backgrounds and Borders
> -----------------------
> Scribe: dbaron
>  summary of issue:
>  dbaron: Brad Kemper vehemently believes that box-shadow should be  
> ignored
>          when border-image is on
>  ...because he thinks they're useful in combination only as fallback

This is true. And fallback is nearly as important for box-shadow as it  
is for border, which we do have already. I will just add a couple  
points below:

>  fantasai: [draws on whiteboard about issue of what to shadow]
>  fantasai explains how box-shadow draws a shadow around the box itself
>    without considering the content of the border box regardless of the
>    transparency of the latter
>  fantasai explains alternative proposal and its inconsistencies
>  <ChrisL> so we have three options
>  <ChrisL> a) never allow drop shadow and border image together (no  
> what
>              authors want)

I believe this misstates the option. First of all, it is a bit like  
saying "never allow border and border-image together", which is  
already true, or "never allow border-radius and border-image  
together", which IIRC has been agreed upon. Second, it is not "drop  
shadow", it is "box-shadow", as in "border box". I think that having a  
drop shadow effect that worked with images would be valuable to  
authors, but it would be very odd to have it work with the images in  
the border but not in the background or list markers, and not cast the  
shadow of the shape of regular dashed or dotted borders. That sounds  
like a separate property to me, something that works more like the SVG  
shadow effect.

>  <ChrisL> b) use the existing drop-shadow with border-image and have  
> the
>              resulting ugliness (not whats wanted either)
>  <ChrisL> c) state that, when border-image is specified, drop-shadow  
> works
>              by forming an offset mask from the alpha channel (what  
> authors
>              probably expect)

Maybe I am not representative here, but it is not what I expect, given  
that it is box-shadow and not drop-shadow, and given that no other  
images anywhere get the drop shadow. Box-shadow operates on the outer  
edge formed by the rectangular border-box, an edge that is no longer  
relevant when the border is suppressed, so I do not expect it to cast  
any "box" shadow.

>  Steve: One other option to get rid of box-shadow.
>  Chris: But it does the job it's designed to do for basic  
> rectangular borders.
>    Chris: It should be clear I'm proposing the third option.
>  Elika: if (c), then (1) do you clip inside the padding box, and
>         (2) for inset shadows, do you clip inside the padding box?
>  Chris: (1) yes, (2) no
>  David: dashed, dotted, double, border-radius?
>  Elika: You do follow border-radius (as you do for backgrounds).
>  Elika: But you don't mask for dashed/dotted.
>  Elika: We're just taking the concept of the CSS border box and  
> making it
>         opaque.
>  David: I wonder whether box-shadow is actually useful given how  
> many ways
>         there are of doing shadows and how many box-shadow covers.

It is very useful as a way to create simple shadows without images.

> ACTION Chris to propose text for how box-shadow should work with  
> border-image
>  fantasai explains the difference between spread and making the  
> shadow bigger

Received on Monday, 9 March 2009 16:28:58 UTC