Talk:Metric typographic units
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There is an article Typographic unit, and I'm wondering if this one should be removed from here and copied to that one, into its "Metric units" section. --Shlomital 20:33, 2004 Oct 8 (UTC)
[edit] Device resolutions in metric
The conversion formula given is very complicated; it could be simplified to 25400/R . Is there any reason not to? Rwxrwxrwx 22:00, 25 October 2006 (UTC)
[edit] Advisory: DIN Section Inaccurate?
I believe the DIN section may be completely confused.
In typography in general, and in CSS, the "font size" is an imaginary box that encloses the maximum size of any characters in the font -- we can think of it roughly as the descender-to-ascender height.
In general typography, "leading" or "interlinear space" is a measurement from the baseline-to-baseline of two lines. CSS "line-height" uses an approach which is effectively the same (for multiple lines), but is calculated and applied differently. The amount of the "font-size" is subtracted from the amount of the "line-height", and the remaining amount of "line-height" is divided in two, and placed above and below the imaginary box of the "font-size". That is, roughly, half the difference goes below the descenders and half goes above the ascenders.
CSS Example
A "font-size" of 12px means the distance from (roughly) the bottom of a "j" to the top of an "h" is 12 pixels.
A "line-height" of 14px accompanying this font size means: 14px minus 12px equals 2 pixels, divided in half equals 1 pixel -- so 1 pixel of empty space goes above the top of the "h", and 1 pixel of empty space goes below the bottom of the "j".
So in the current article, if the CSS examples are correct then the description of the DIN system is all wrong. The DIN system as described has one of the measurements being the height of the letter "H" -- but CSS does not use this measurement for either "font-size" or "line-height".
Altenately, if the description of the DIN system is correct, then you cannot currently specify fonts in CSS with the DIN system. The DIN specification of "SG/OH" is not the same as the CSS notation "font: 4.3mm/6.0mm" or "font-size: 8.6mm; line-height: 12.0mm".
Also note that the current DIN description seems to be confused even within itself -- it seems to have "font size (Schriftgröße)" and "font height (Oberhöhe)" reversed.
I will see if I can find the actual DIN specification. In the meantime I'm putting a warning note in the article.
The content of the article -- and even the article title -- seem to come directly from this Web page which is definitely not accurate in at least some respects:
http://www.cl.cam.ac.uk/~mgk25/metric-typo/
And the Wikipedia article text seems to mangle the info further, giving "SG/OH" as the specification format, when the source Web page seems to give "SG(as designed)/SG(as desired)".
Additionally, this whole subject is confounding two separate issues: specifying existing digital fonts in millimeters (a trivial thing, which contrary to the article, is possible in most current word processors/page layout apps and in CSS) -- and regularizing the actual size of font characters with their supposed sizes (which is not specifically a metric issue, could be done with point sizing as well).
So as far as simple specification of existing fonts in millimeters, it's really a non-subject -- you can do it if you wish to. And I'm thinking proposals for regularization of actual font character sizes should be a different article, on that subject.
I don't have more time to spend on this -- I'm adding another warning at the top of the page that the whole article (except for the Device resolutions in metric section is not accurate and should be deleted.
