Re: A proposal for units in GTK+

["Gustavo J. A. M. " Carneiro <gjc inescporto pt>]

On Mon, 2003-02-03 at 22:30, Noah Levitt wrote:
> CSS seems to define an em as the font's height.
> http://www.w3.org/TR/REC-CSS1#length-units
> 
> H1 { margin: 0.5em }      /* ems, the height of the element's font */
> 
> Noah
> 



The foremost tool for writing scalable style sheets is the "em" unit,
and it therefore goes on top of the list of guidelines that we will
compile throughout this chapter: use ems to make scalable style sheets. 
Named after the letter "M", the em unit has a long-standing tradition in
typography where it has been used to measure horizontal widths. For
example, the long dash often found in American texts (--) is known as
"em-dash" since it historically has had the same width as the letter
"M". Its narrower cousin (-), often found in European texts is similarly
referred to as "en-dash".

 The meaning of "em" has changed over the years. Not all fonts have the
letter "M" in them (for example Chinese), but all fonts have a height.
The term has therefore come to mean the height of the font - not the
width of the letter "M". 


http://www.w3.org/WAI/GL/css2em.htm

> 
> On Mon, Feb 03, 2003 at 23:20:47 +0100, Matthias Clasen wrote:
> > On Mon, 2003-02-03 at 21:33, Jonathan Blandford wrote:
> > > 
> > > Additionally, I don't know if we want to distinguish between height
> > and
> > > width of a font, as an 'em' is technically only a horizontal unit of
> > > measure.  Adding two font-based units seems to be possibly too
> > > confusing, though.
> > 
> > The TeXbook says (p.60)
> > 
> > em is the width of a "quad" in the current font;
> > ex is the "x-height" of the current font.
> > 
> > [...] It is generally best to use em for horizontal measurements and ex
> > for vertical measurements that depend on the current font.
> > 
> > 
> > But that might be more relevant for typography than for UI design...
> > 
> > Matthias
> >  
> > 
> > 
> > _______________________________________________
> > gtk-devel-list mailing list
> > gtk-devel-list gnome org
> > http://mail.gnome.org/mailman/listinfo/gtk-devel-list
> _______________________________________________
> gtk-devel-list mailing list
> gtk-devel-list gnome org
> http://mail.gnome.org/mailman/listinfo/gtk-devel-list
-- 
Gustavo Joćo Alves Marques Carneiro
<gjc inescporto pt> <gustavo users sourceforge net>