[texhax] font metrics

[Karl Berry]

    I would like to discuss about the slant parameter in the Tex font metric 
    file. As far as i have come to know is that it is equal to the tangent of 
    the angle in degrees from the vertical in the counter-clockwise direction.

It is?  That is not exactly clear to me either.  tftopl.web (et al.) says:

  param[1]=@!slant| is the amount of italic slant, which is used
  to help position accents. For example, |slant=.25| means that when you go
  up one unit, you also go .25 units to the right. The |slant| is a pure
  number; it's the only |fix_word| other than the design size itself that is
  not scaled by the design size.