An abbreviation and filename extension
for Printer Font Metrics
file, which is used with Type 1
fonts. These files coexist with related PFB
files, and together represent a single typeface. PFM files contain data used to display a font
on-screen. Type managers use this vector
data and rasterize
it. It then scales
the image to the proper size and smooths
Multiple master fonts do not use PFM files, they use a somewhat similar file called a Multiple Master Metrics (MMM) file.
Compare with TrueType fonts, which contain both the screen and printer data in a single file.