Aspect Ratio Results

I tested the following fonts using my aspect ratio tester with a 100px Windows font size, using the Mozilla browser for Windows (in May of 1999).

• The "x-height" column gives the height of typical lowercase letters. "approx" means that the heights of lowercase letters varied, so the x-height isn't necessarily the height of the lowercase letter x, and I used what I thought was the correct x-height.
• The "Font Size" column gives the separation between two lines of text with a line-height of 1.

Hopefully, all the values are only plus or minus 1px, but I could be off by two. "exact" means I enlarged the image rather than judging pixels.

These data show the ratio of the requested height of the font to the actual height of the font returned (as given by its metrics, I assume). That is, all the fonts here should be separated by 100px, but Mozilla uses the height from the font metrics (?) to determine the actual line-height, so the separation of the lines shows how big the font claims to be.

Differences between requested and actual font size cause a number of problems for browsers. If browsers implemented ex units or the font-size-adjust property, computation of aspect ratios or x-heights would be an additional such problem. The aspect ratio that uses the requested font size is just the number in the "x-height" column divided by 100. The aspect ratio that uses the actual font size is the one given in the "Aspect Ratio" column.

See a post I made to c.i.w.a.s for an explanation of the issue from the beginning.

(Back to CSS Information, David Baron)

LDB, dbaron@dbaron.org, 1999-05-21 (?), 1999-10-09