Values in font-size-adjust example

In the description of 'font-size-adjust' in REC-CSS2 [1] there are given
several example fonts with their corresponding values.

I wondered how you find these values?

E.g., Verdana is being said to have a value of 0.58 there. According to the
TTF version of my copy, 2.43, the x-height is 1117, with 2048 units per em.
1117 / 2048 ~= 0.545 -- not 0.58. I've been told [2] that you find a similar
value when measuring an printed out "x" (139mm@720pt; 139/254~=0.547).
Any combination of other metrics (e.g. ascender - descender) to get a font
height of around 1926 (1117/1926=0.58) failed, although caps-height -
descender comes close (1117/(1489+423)=0.584), but only for Verdana.

Verdana:         0.58 -- 1117 / 2048 ~= 0.545
Comic Sans MS:   0.54 -- 1105 / 2048 ~= 0.534
Trebuchet MS:    0.53 -- 1074 / 2048 ~= 0.524
Georgia:         0.50 --  986 / 2048 ~= 0.481
Minion Web:      0.47 --  906 / 2000 == 0.453
Times New Roman: 0.46 --  916 / 2048 ~= 0.447
Gill Sans:       0.46 --  920 / 2048 ~= 0.449

Are the values wrong, inaccurate, derived from different versions, or is the
calculation method flawed?

Btw.: AFAICS the example is being reused unchanged in the current CSS3 Fonts
working draft.

Christoph Päper (not that font-size-adjust was widely supported yet)

[1] <http://www.w3.org/TR/CSS2/fonts.html#propdef-font-size-adjust>
[2] <090520031943391755%nhtcapri@rrzn-user.uni-hannover.de>

Received on Monday, 12 May 2003 22:02:00 UTC