Re: Bug Report: CSS3 Validation of "ch" unit

Intrigued by the following bug report from Ryan Foster, I read
the CSS 3 spec. on units, and read -- to my surprise -- the
following :

em  	the font size of the element (or, to the parent element's font size if set on the 'font-size' property)
ex 	the x-height of the element's font

Is there any reason why "ex" does not also reference
the parent element's font size if set on the 'font-size' property ?

Philip TAYLOR
--------
Ryan Foster wrote:
> When set to CSS3, the CSS Validator states:
> 
>     Value Error : min-width
>     <http://jigsaw.w3.org/css-validator/nullvisudet.html#propdef-min-width>
>     Unknown dimension 15ch
> 
> While the CSS3 Values and Units <http://www.w3.org/TR/css3-values/> 
> draft specification states <http://www.w3.org/TR/css3-values/#relative0>:
> 
>     ch:  The width of the "0" (ZERO, U+0030) glyph found in the font for
>     the font size used to render. If the "0" glyph is not found in the
>     font, the average character width may be used. How is the "average
>     character width" found?
> 
> The Validator should mark "ch" as a valid unit when set to CSS3.  The 
> same error occurs in the development version 
> (http://qa-dev.w3.org:8001/css-validator/).

Received on Monday, 26 October 2009 10:55:12 UTC