11.1.2 Proofing with Metafont

While creating fonts, it is useful to enlarge the character shapes enough to be able to make out small details. This blowing-up process is called proofing. Metafont works together with GFtoDVI, another program created as part of the TeX project, to do this.

You can make two kinds of proofs with Metafont: gray proofs and smoke proofs. Metafont calls the former proof mode, and the latter smoke mode. proof mode is the default, so if you do not assign to mode at all, you get gray proofs. To get smoke proofs for a font foo, you run Metafont as follows:

mf '\mode:=smoke; input foo'

(See the preceding sections for general information on running Metafont.) In proof or smoke mode, by default Metafont will display the characters online as it runs (if you are on a terminal capable of this, e.g., running under X). If you aren't interested in seeing this online output, you can say `nodisplays;' on the command line.

In both kinds of proofs, the font is produced at a very high resolution, typically thousands of pixels per inch, to minimize (or eliminate) distortion due to rasterization difficulties. To be more precise, the resolution is chosen so that the designsize of the font fills proof_size inches; by default, proof_size is 7, which works well enough for both letter-size and A4 paper.

In order to calculate this, Metafont must also know the resolution of the final output device. This is called proof_resolution, and is 300 by default.

You can change the values of proof_size and proof_resolution on the command line; the actual calculation is done in `bzrsetup.mf'.

After running Metafont, you will have a GF file, e.g., `foo.2602gf'. You can then make a DVI file you can preview or print with:

gftodvi foo.2602gf

This creates `foo.dvi'. In the DVI output from GFtoDVI, each character in the font has its own page. Some additional information is also present, as follows:

In proof mode, the character shapes are printed in a "gray" font, and the starting and ending points of each spline (or line) in the character outline are shown. (Thus, you can see if Limn did a good job choosing those points.) If you set proofing > 2, the control points for each spline will also be shown. If a point would otherwise overlap with others on the output, an equation is put off to the right defining where it appears.

In smoke mode, the character shapes are printed in black; if you put the output on the wall and stand back, you can get an idea of how the font is coming along. The character is also shown at its true size off to the right (assuming you have made the font at the true-size resolution, of course).

You may find that the extra information to the right of the character ("overflow equations" in proof mode; the true-size character in smoke mode) is being lost off the edge of the page. You can change where GFtoDVI puts this with the `-overflow-label-offset' option to GFtoDVI.

See the Metafontbook and the GFtoDVI documentation for more details.