POV-Ray

As for setting the metrics, note that font metrics are intrinsic to a font and therefore cannot be modified.

Also, for getting most of the metrics, this should already be possible by clever use of the bounding information. So all one would need to write is a macro that outputs them accordingly.

It’s rash to close a request that has been otherwise without comment for months a few hours after someone finally does make a comment. There’s no way for anyone to reply further to the comments below.

Thorsten, note that bounding information only gives you a subset of font metrics - not to mention that it's not clearly documented which of the information it gives: For instance, does the bounding box height include leading? Does it include ascenders and descenders when the text string doesn't? And obviously the bounding box must be a poor way to compute the advancement for italic fonts, because for such fonts some of the glyphs are wider than the advancement.

Also need information like the base height of a font, so that you can do things like align text to the baseline of the font not the bottom of "g", "q" or "p". (Sorry if maybe I didn't explain that clearly enough.) Just like how centering a font doesn't necessarily mean the same thing as centering the bounding box.

Finally see here about how fonts can have different aspect ratios that can't be described completely just by measuring their bounding boxes:

http://webdesignernotebook.com/css/the-little-known-font-size-adjust-css3-property/