RE: Equal width/height for grouped elements

Dynamic measuring when the items may not be on the same page can cause
some really bad performance. If not all objects are on the same screen,
there could be some problems if the size is not constant. Size can
change due to location of things on either side when the page is laid
out.

I understand what you are getting at, but see all kinds of problems to
algorithms to calculate sizes that are non-trivial to deal with in some
cases.

Paul



-----Original Message-----
From: www-style-request@w3.org [mailto:www-style-request@w3.org] On
Behalf Of Daniel Beardsmore
Sent: Thursday, March 08, 2007 11:50 PM
To: www-style@w3.org
Subject: Re: Equal width/height for grouped elements


Markus Jonsson wrote:
> Hi!
> There's no way to ensure that two or more elements will be presented
with exactly the same width and/or height, unless they are given an 
> absolute width. Sometimes you don't want to set absolute measures,
instead they should depend on the content, which may not be forseeable.
> ...
> But if you want them placed in very different parts of the document,
it's not possible to have this effect.

My favourite example of this is a page or two on my site where I have
some code 
examples in elements with pale green backgrounds. I'd like these
elements to 
share the same width, but, I don't like them being the full width of the
page.

I proposed similar ideas here a short while back, and a few people
understood 
what I meant. It's not wildly popular and it might take more interest
before 
anyone decides to run with it, but Mikko Rantalainen offered a way to
express it 
that's in line with CSS:

   .thumbs li { height: auto; width: auto; sizing-group: "thumbnails"; }

   That is, redefine "auto" for height or width to check if the element
   belongs in an "sizing-group" and if it does, compute the height or
width
   to be the maximum of all elements in that group when contents of
those
   elements are shrink-wrapped (and define further what
"shrink-wrapping"
   means). If height or width is set to some other value but auto, then
the
   sizing-group magic wouldn't apply.

I don't know if your own suggestion is viable or not (although I find
yours far 
more readable, as well as mine, but mine was branded invalid), but I am
glad to 
see someone else draw the same conclusion, that it doesn't matter how
large 
something is on a page, as long as it's consistent.

The reason we may all be struggling with it is because it's a new
concept to 
layout. In print, it doesn't exist, because we know how wide the paper
is that 
we're going to be printing on, or the aspect ratio of it if we're going
to scale 
it, as well as the text size, typeface etc. If we want a bunch of items
the same 
size, we simply set them to be the same size and we're done.

On the Web, we don't have this knowledge: it's safest to let the
user-agent 
decide the size and layout for us and often, we don't have any choice
anyway. 
But we do need to be able to find out what layout decisions were made
(based on 
font size, window/page width etc), and factor them into the rest of the
design.

Received on Thursday, 8 March 2007 21:27:33 UTC