# -F: specification

This specification has the format of <ss>.<ds>=<so>.<do>. When ^s matches <so> and ^d matches <do>, they are substituted to <ss> and <ds>, respectively. Dviout will search again in the directories of -TEXPK:. You can specify more than one substitution by delimiter of semicolons ;. Until found, dviout will keep searching
the substitution font from the beginning of the -F: specification.
The font names are specified in <ss> and <so>. The resolutions (dpi) are specified in <ds> and <do>. The following strings have special meanings:
<so>=space Matches all of the font names
<do>=space Matches all of the resolutions
<ss>=space Represents the original font name (^s)
<ds>=space Represents the original resolution (^d)
<ds>=! Represents the default resolution
<ds>= Represents the Font Metric File with the extension changed to tfm. In this case, dviout will search the font metric file from -TEXFONTS:, not -TEXPK:.
Examples
-F:cmr10.=.
^s is replaced by cmr10(^d keeps its original value)
-F:.t=.
Dviout searches the font metric file corresponding to the original font in the directory specified by -TEXFONTS: (simply, this is identical even for .t).
-F:.!=.;cmr10.=.;cmr10.!
In this case, ^s might be cmcsc10, ^d might be 320, and the default resolution might be 300. Then, substitution for (cmcsc10, 320) will be done by searching successively (cmcsc10, 300), (cmr10, 320), and (cmr10.300).
In this example, only the last part can be omitted. For this case, dviout interpret "=." before cmr10.!. (cf. Handling Missing Fonts)