W3C home > Mailing lists > Public > www-style@w3.org > February 2004

RE: [CSS2.1] Visual formatting model details

From: <Matthew.van.Eerde@hbinc.com>
Date: Fri, 6 Feb 2004 13:55:56 -0800
Message-ID: <B8B9965E9A4B1948839F37ADCB58E9D52D1607@exchange.hbinc.com>
To: ian@hixie.ch, fantasai@escape.com
Cc: www-style@w3.org

>    A.  w > wmax > wmin > 0
>    B.  h > hmax > 0
>    C.  hmax/h > wmax/w
>    D.  w*hmax/h < wmin

There are no numbers that satisfy these inequalities.

C can be rewritten as wmax < w * hmax / h
D can be rewritten as wmin > w * hmax / h

But this implies that wmax < wmin, which contradicts A

> -----Original Message-----
> From: Ian Hickson [mailto:ian@hixie.ch]
> Sent: Thursday, February 05, 2004 11:31 AM
> To: fantasai
> Cc: www-style@w3.org
> Subject: Re: [CSS2.1] Visual formatting model details
> 
> 
> 
> On Thu, 5 Feb 2004, fantasai wrote:
> >>
> >> The bit that is undefined is the "finding the preferred 
> width"s part. I
> >> don't see the problem here. Mozilla uses a different definition of
> >> "preferred minimum width" than the spec (one that is not constant).
> >
> > I don't understand how making the "preferred minimum width" variable
> > can give you Mozilla's rendering.
> 
> Just define the preferred minimum width as the width Mozilla achieves.
> 
> 
> >> In any case I'm not convinced your dscription of the 
> "improved" definition
> >> is actually better, since it implies discontinuities in the width.
> >
> > I don't understand what you mean by "discontinuities in the width".
> 
> Take your example below and slowly increase (or decrease) the 
> width of the
> containing block. Does the inner block width snap? If so, there are
> discontinuities. I would rather the width do this:
> 
>   width
>  of inner
>   block
>     |
>     |    ________________________
>     |   /
>     |  /
>     |_/
>     |
>    -+---------------------------- width of containing block
> 
> ...rather than:
> 
>   width
>  of inner
>   block
>     |
>     |       _______________________
>     |     _|
>     |   _|
>     |__|
>     |
>    -+---------------------------- width of containing block
> 
> (not to scale)
> 
> 
> > 3. hmax/h > wmax/w
> >                          wmax      w
> > |-------------------------+-------+--------> width
> >              hmax                  h
> > |-------------+-------------------+--------> height
> 
> That's hmax/h < wmax/w.
> 
> 
> >>> Here's the problem statement:
> >>>  1.  w > wmax
> >>>  2.  h > hmax
> >>>  3.  hmax/h > wmax/w
> >>>  4.  w*hmax/h < wmin
> >>
> >> Yes, I understand the maths fine, what I would like to see 
> are values for
> >> those variables that actually demonstrate the problem, 
> such that we are
> >> able to write a testcase.
> >
> > w = 100a
> > h = 100b
> > hmax = 70b
> > wmax = 90a
> > wmin = 80a
> >
> > a = units for width
> > b = units for height
> > They don't have to be the same units.
> 
> Let a = b = px, so w = 100px, h = 100px, hmax = 70px, wmax = 90px.
> 
> hmax/h = 70/100. wmax/w = 90/100.
> 
> According to your third inequality, 0.7 > 0.9.
> 
> Thus those numbers don't work.
> 
> This is the problem I am having with your issue here. I don't 
> disbelieve
> there is a problem. I just haven't been able to come up with 
> the numbers
> that actually fit the criteria you specify.
> 
> When I say I want to visualise this I actually mean I want to create a
> test case and see it for myself using real CSS and real 
> browsers, not that
> I have any trouble with the maths. The problem is that while it is
> sometimes possible to come up with cases that mathematically 
> are indeed a
> problem, sometimes those cases are only relevant when you 
> start invoking
> negative numbers or imaginary numbers.
> 
> The full version of your criteria (and the version I had written on a
> piece of paper here before I gave up trying to solve it) are thus:
> 
>    A.  w > wmax > wmin > 0
>    B.  h > hmax > 0
>    C.  hmax/h > wmax/w
>    D.  w*hmax/h < wmin
> 
> -- 
> Ian Hickson                                      
> )\._.,--....,'``.    fL
> U+1047E                                         /,   _.. \   
> _\  ;`._ ,.
> http://index.hixie.ch/                         
> `._.-(,_..'--(,_..'`-.;.'
> 
Received on Friday, 6 February 2004 16:56:13 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 27 April 2009 13:54:26 GMT