11.3 Type 3 PostScript fonts and BZRto

Type 3 PostScript fonts are not defined in a singular format, as are Type 1 fonts (see the previous section). Rather, they are general PostScript programs which happen to meet the PostScript language's (liberal) requirements for being a font. They can therefore be used with any PostScript interpreter.

BZRto generates a Type 3 font `foo.pf3' from an input BZR file `foo.bzr' if you specify the `-pstype3' option, as in:

bzrto -pstype3 foo

We do not know of any conventional extension for Type 3 fonts; we made up `pf3' to stand for "PostScript font Type 3".

The most important part of a Type 3 font is the BuildChar routine, which does the actual rendering from the character program. Unlike Type 1 fonts, whose BuildChar routine is built into the PostScript interpreter, each Type 3 font supplies its own BuildChar routine.

The Type 3 fonts output by BZRto use a BuildChar routine defined in a separate file `bzrbuildch.PS' (distributed in the `bzr' directory). They use the PostScript run command to read that file; so if you want to download one to a printer (which naturally will not have access to the file on your computer), you must replace the run command with the contents of the file. For PostScript interpreters which run on a host computer, such as Ghostscript, you have to install `bzrbuildch.PS' in a directory where it will be found, but you need not modify the fonts.