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Re: My point is a point is a point

From: Matthew Brealey <webmaster@richinstyle.com>
Date: Tue, 01 Aug 2000 12:34:03 +0100
Message-ID: <3986B5AB.3214@richinstyle.com>
To: Sho Kuwamoto <sho@macromedia.com>
CC: www-style@w3.org
Sho Kuwamoto wrote:
> 
> Which is why (for better or for worse) a point is defined in terms of visual
> angle in CSS. 

I think you're getting confused with pixels.

http://www.w3.org/TR/REC-CSS2/syndata.html#length-units

Relative units are: 

em: the 'font-size' of the relevant font 
ex: the 'x-height' of the relevant font 
px: pixels, relative to the viewing device [and there is a explanation
of how pixels should be rescaled]

--
Whereas:

Absolute length units are only useful when the physical properties of
the output medium are known. The absolute units are: 

in: inches -- 1 inch is equal to 2.54 centimeters. 
cm: centimeters 
mm: millimeters 
pt: points -- the points used by CSS2 are equal to 1/72th of an inch. 
pc: picas -- 1 pica is equal to 12 points. 

--

> Since football stadium signs are usually read from a large
> distance, a "point" according to this definition would be rather large.

No, a pixel at that definition would be large (or rather, a specified
number of pixels would result in a large font on that device).

Thus 72pt on our stadium sign would be 1-inch high, whereas 96px, which
is what most people actually mean when they specify 72pt, would be
rescaled (hopefully) so that it has the same apparent size as on the
original device (although I think there are other factors that will
affect font sizes on devices designed for viewing at long distances;
while the pixel rescaling rules are useful on devices that have a
viewing distance in the same range as a VDU, for such devices factors
such as the quality of the image will be important (I'm also not sure to
what extent the viewing distance is affected by the ability of the eye
to focus)).

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Received on Tuesday, 1 August 2000 07:34:43 GMT

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