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Re: [css3-background] A few points about the current module

From: Laurens Holst <lholst@students.cs.uu.nl>
Date: Sat, 13 Aug 2005 11:59:41 +0200
Message-ID: <42FDC48D.8050706@students.cs.uu.nl>
To: Bert Bos <bert@w3.org>
CC: www-style@w3.org

Bert Bos wrote:
> That's an interesting idea and the syntax wouldn't become much more 
> complicated than it is now. But on the other hand, I think most of the 
> use cases will involve putting images along the edges to create the 
> impression of a frame. And for that there is the 'border-image' 
> property. 'Border-image' has the nice feature that it creates nine 
> areas while only requiring the designer to draw a single image, which 
> is also more efficient in download time.
> Maybe there are cases where 'border-image' isn't enough and you also 
> can't achieve the effect you want with overlapping images, but are they 
> important enough?
The most important use case is if you want to do ‘rollovers’ - that is, 
have multiple states of the background in one image, and only show the 
part of the image that corresponds to the current state. Currently, 
these rollovers are not possible if you want to offset them from the 
bottom right. Also, it needs parts of the background to be masked, and 
this is currently done - it would be nicer if you could just point  a 
region to display.

Also, with e.g. rounded corners, it is quite possible that the designer 
wants to have a border that is smaller than the border images. e.g. the 
curve of a rounded corner is 10x10 pixels, yet the page author wants the 
box to only have a padding of 5px. I do not think border-image allows 
for this... Which I think is actually a small design flaw in 
border-image, but ah well.

Another use case is an image of a closing quote mark at the bottom right 
of a blockquote. Currently, the designer can only position this image at 
the bottom right or in percentage distances, and for pixel-positioning 
he has to resort to adding padding to the image itself.

If the argument ‘isn’t border-image enough?’ would be valid, why would 
percentage values, more particularly: percentage values of free space 
instead of simply percentages of the width, be in the spec? border-image 
can do it, right? Also, why would background-position have to exist at 
all, surely if border-image can take care of right and bottom offsets, 
it can also take care of top and left offsets?

Basically, border-image doesn’t solve the problem at all. We *are* 
already able to position things at the right and bottom border. The 
problem is when you want something to not be placed directly adjacent to 
the border, something that border-image can’t do.

Looking forward to the outcome of this discussion,


Ushiko-san! Kimi wa doushite, Ushiko-san!!
Laurens Holst, student, university of Utrecht, the Netherlands.
Website: www.grauw.nl. Backbase employee; www.backbase.com.
Received on Saturday, 13 August 2005 09:59:41 UTC

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