User Guide

and 255 points. The width of a bitmap character is limited
to 254 points. At the larger point sizes, this may require you
to limit the width of an outline character. Fontographer
avoids trouble by automatically limiting wide bitmap
characters to 254 points, even if the character is calculated
to be wider.
Generating bitmaps doesn’t necessarily mean that
Fontographer will generate a .FON file. Fontographer will
keep those bitmaps in memory and in its database file until
you decide to remove them.
PostScript background
PostScript is a programming language developed by
Adobe Systems, Inc. to drive high-resolution printers.
Invented as a standard page description language with a
well-documented behavior, it is used on printers produced
by a number of different manufacturers.
PostScript’s generality allows any picture to be described
as a program; this is how fonts are constructed. Each letter
is described by a small program which draws the letter
outline using PostScript graphic commands. In order to
print the character on a page, this character drawing
program is run by the printer control software to draw and
fill the outline, generating a high-resolution bitmap. The
bitmap is generated at the current point size, and then
copied to the page at the appropriate location.
Bezier curves
The PostScript graphic commands available are straight
lines, arcs, and Bezier curves. A Bezier curve has control
points which allow changing the shape of the curve. An
arc has uniform curvature everywhere, but a Bezier curve
allows non-uniform curvature. This property is useful in
describing complex shapes with only a few well-chosen
control points. Additionally, Bezier curves have desirable
smoothness properties which lend themselves to efficient
generating programs.
Another useful property of Bezier curves is that it is very
easy to guarantee smooth joins at the endpoints of the
curve. Smooth tangent joins are very important to high
Fontographer User's Manual
C: General information Page #6