Re: The Spec: On the `edge' of despair

On Tue, Nov 15, 2011 at 7:22 AM, Michael Witten <> wrote:
> The CSS 2.1 specification uses some very confusing (if not erroneous)
> terminology in describing the fundamental concepts of the Box Model:
> The uses of the words `perimeter', `edge', `width', and `box' are
> completely unreasonable unless the following statements are
> considered reasonable:
>    * The `perimeter' of an area really means the `outer perimeter'
>      of an area.
>      The word `edge' is a suitable synonym for the word `perimeter'.

Yes, this seems reasonable.  The spec says exactly that.

>    * The phrase `four content edges' means:
>          top content edge, right content edge,
>          bottom content edge, and left content edge
>      which doesn't make sense until the next statement is discovered
>      by reading further into the specification.
>      [Repeat this statement for each of `padding', `border', and
>      `margin' in place of `content'.]

I don't understand which statement you mean by "the next statement".
In any case, this seems clear and obvious in the spec.

>    * The phrase `content box' means "the box's content area".
>    * The phrase `padding box' means "the box's padding area".
>    * The phrase `border box'  means "the box's border area".
>    * The phrase `margin box'  means "the box's margin area".

This equivalence isn't stated explicitly, but it appears obvious.

>    * The word `width' is a suitable synonym for the word `area'.

No, that's not true, and it's not suggested in the text.  The "width"
talked about in this chapter is the distance between a box's edge and
the nearest enclosed box's edge. This can be different for each of the
four edges.  It's almost never synonymous with "area", as even when
the padding is zero, for example, the padding box will have the same
area as the content box.

>    * The sentence:
>          The four content edges define the box's content box.
>      really means:
>          The content edge defines the box's content area.

I don't see a difference here.
[snip identical statements about padding/border/margin]

>    * The phrase `top edge' is equivalent to the phrase `top of the edge'
>      (or at least the `edge' in `top edge' has no meaning by itself).

No, it refers to the top edge - that is, the top segment of the
perimeter.  I think your trouble here is that you're stuck on the fact
that the *entire* perimeter of the box is called an "edge", and then
that edge is broken up into four sub-edges.  An edge can be made of

(Edge has ceased to look like a word to me. :/ )

Overall, I'm not seeing anything in particular that seems strange or
incorrect in this chapter.  You do make one valid point - that we
don't specifically state that the terms "XXX box" and "XXX area" refer
to the same thing - but that equivalence seems trivial to draw.


Received on Tuesday, 15 November 2011 18:14:29 UTC