Re: [css3-background] comments

Bert Bos wrote:
> On Saturday 09 April 2005 14:08, Anne van Kesteren wrote:
> 
>>I think the specification should have a section that clarifies the
>>terms SHOULD, MUST, etc. The rest of the comments I gave per section.
>>I might have missed a few bits, I'll reread the draft when it becomes
>>last call.
>>
>>
>>* 1. Dependencies with other CSS 3 Modules
>>
...
> How about reducing it to
> 
>   - Box Model (we need content edge, padding edge and border edge)
>   - Absolute Positioning (in particular the section
>     “Elaborate description of Stacking Contexts”)

Absolute Positioning should be depending on Backgrounds, not the other
way 'round. You need backgrounds support to do stacking of backgrounds,
but you don't need absolute positioning support to do backgrounds in
static flow. You /do/ need the basics of the box model to do backgrounds
in any flow, though. A dependency on CSS2.1 section 8.1 is probably
sufficient for this module.

CSS3 Backgrounds also depends directly on CSS3 Color and CSS3 Values and
Units. We are using the CSS3 Color <color> type and the CSS3 Values and
Units <length>, <percentage>, and <url>. A dependency on CSS2.1, as Anne
suggests, would preclude using new features defined only in CSS3.

>># If 'background-repeat' or 'background-position' has more
>># comma-separated values than 'background-image', the series of
>>values # is repeated as needed.
>>
>>As the editor's note already mentioned, it makes more sense for
>>'background-image' to determine the number of layer and let all the
>>extra values specified be ignored.
> 
> I think I also like it better to make 'background-image' determine the 
> number of layers: you only have to look in one place to know how many 
> there are. But there is the case where you want a single image in 
> multiple places (for example, one in each corner) and then you only 
> need to specify it once. We'll see.

I think that the obviousness of letting background-image determine the
number of layers outweighs the convenience of not having to type the
URL in a few extra times.

>>I think it might be wise to specify how 'space' should work. I am
>>aware of a large discussion how 'letter-spacing' should be
>>implemented exactly and it would  be nice if this module would
>>specify in more detail how it should work. (Personally I think the
>>space at the edge should be halve the space that is between the
>>images.)
> 
> I agree that being more specific is a good thing. I just don't know yet 
> what the right answer is: the final image against the edge, half the 
> space away from it or a full space away from it?

The image's edges should meet the box edges unless only one tile fits,
in which case it should be centered.

> Something like
> 
>     background-position: NW 0% 0%, SE -5px -5px
> 
> to put the first image in the top left (northwest) corner and the second 
> a little inside the bottom right (southeast) corner?

I think introducing another coordinate naming system when we already
have one that means the same thing is a bad idea. TL/TR/BL/BR matches
the rest of CSS much better.

~fantasai

Received on Wednesday, 13 April 2005 22:41:37 UTC