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Units Re: Relative Font Size

From: Charles McCathieNevile <charles@sidar.org>
Date: Wed, 18 Jun 2003 17:38:28 +0200
Cc: "Scarlett Julian \(ED\)" <Julian.Scarlett@sheffield.gov.uk>, <w3c-wai-ig@w3.org>
To: "John Foliot - WATS.ca" <foliot@wats.ca>
Message-Id: <E8901B4F-A1A2-11D7-AE63-000A958826AA@sidar.org>

Somewhere deep in WAI archives from 2000 is a discussion of using em to 
size image icons. It should work, and I believe it turned out that in 
some browsers it did work even back then - combined with a scalable 
format like SVG or flash it would sometimes be helpful for people who 
have low vision and can't quite make out the details of a chart...

This is one case where em and percentages are going to do different 
things. The fact that em is firmly tied to the font is helpful for 
scaling some stuff, because percentages are sometimes related to the 
font and sometimes to the viewport (and in some bugs they're related to 
a magic unguessable number).

by the way, ex is also a unit related to the font size - but I don't 
see it used much. (I forget the exact definition, which is in the spec, 
but I think it is the width of the font, or the height of a lower case 
letter, or something).

Cheers

Chaals
On Wednesday, Jun 18, 2003, at 17:11 Europe/Zurich, John Foliot - 
WATS.ca wrote:

>
> Julian,
>
> May I humbly point you to http://wats.ca/resources/relativesizing/20.  
> In this case, by using ems I can apply the sizing to more than just 
> fonts.  To that end then, ems would be more "practical"?
>
> Just my $.03 (which given the current US/Canadian exchange rate is 
> about $.02...)
>
>
--
Charles McCathieNevile                          Fundación Sidar
charles@sidar.org                                http://www.sidar.org
Received on Wednesday, 18 June 2003 11:39:17 GMT

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