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Re: [CSSWG] Minutes and Resolutions 2009-02-04: box-shadow and border-image

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Thu, 5 Feb 2009 12:20:44 -0600
Message-ID: <dd0fbad0902051020yc1d331bh333e3aad419d1a67@mail.gmail.com>
To: Håkon Wium Lie <howcome@opera.com>
Cc: Brad Kemper <brad.kemper@gmail.com>, fantasai <fantasai.lists@inkedblade.net>, www-style@w3.org

On Thu, Feb 5, 2009 at 12:02 PM, Håkon Wium Lie <howcome@opera.com> wrote:
>
> Also sprach Brad Kemper:
>
>  > >  RESOLVED: box-shadow is not suppressed by border-image
>  > >  RATIONALE: It's useful in many cases, and the author can suppress
>  > >             it himself as needed.
>  >
>  > Can this be reopened? I strongly disagree with the reasoning above,
>
> I argued for not suppressing border-shadow, for two reasons:
>
>  - properties should be independent of each other, as much as
>   possible. Unless there are strong reasons for it, setting a value
>   on one property shouldn't affect the interpretation of other
>   properties.

This is very reasonable, and is a strong reason for keeping current
spec behavior.  I think there are some decent reasons otherwise,
though.

>  - having box shadows on boxes with border-image seems useful. The
>   argument that one can create these shadows in pixmap editor is not
>   convincing. I don't want to open a pixmap editor, I want to set
>   shadows in CSS

This I simply don't agree with.  The majority of the time, I (and I
mean I, personally) will be using border-image to create
non-rectangular shapes.  box-shadow will be more than useless in these
cases - it will produce a completely unintuitive shadow that doesn't
correspond to any visible edge.

You say you don't want to open an image editor.  This *is* a valid
concern in *normal* cases, where you are not using an image editor at
all and just want to add a shadow to your box.  If you're using
border-image, though, you're almost certainly creating the image in an
image editor, where adding a semi-transparent shadow is not difficult.

Basically, I think there's only a single use-case where you want both
box-shadow and border-image to be displayed at the same time, and
that's the case where you have a perfectly rectangular border-image
with no transparency on the edges, and you don't want to add a shadow
to the border-image in an image editor.

I think this will be a rare use-case in practice, and will be far
overshadowed by cases where displaying both at the same time will
produce bad results.

So, we're back to the first reason you provided.  Is the ability to
specify both and gain useful fallback behavior enough of an advantage
to overrule the desire to keep property interaction simple?  I think
so, but reasonable people may differ on this issue.

~TJ
Received on Thursday, 5 February 2009 18:21:19 GMT

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