Fonts & Encodings

C.3. Type 1 Fonts

In this section, we shall describe the most widely available fonts on Earth (at least if we extrapolate from office-automation software, where TrueType seems to be the leader). Incidentally, Adobe has managed—God knows how—to make the structure of these fonts an ISO standard! It is part 3, "Glyph Shape Representation",^[C-11] of ISO standard 9541, Information Technology— Font Information Interchange, of May 1, 1994 [195].

^[C-11] Reading this specification is a real thrill since one finds in it all the properties of Type 1 fonts—and even a few hints on the internal workings of the black box that is the Type 1 font renderer—properties described in a much more serious style than the Adobe specification [21]. One feels that Adobe has put a big effort into rewriting the specification in ISO's jargon. Note that the name "Adobe" does not appear anywhere and that the name "PostScript" appears just once in a footnote in the appendix on compatibility with existing software.

The structure of these fonts is quite close to that of Type 3, with a few exceptions of considerable importance:

• First, Type 1 fonts do not use the standard PostScript operators to describe outlines; instead, they use a smaller set of special operators.

• Second, they have a number of tools for optimizing rasterizations (the famous hints).

• Finally, they are binary, encoded, and encrypted.

A Type 1 font consists of four components:

• The "public dictionary" (global parameters written in plain text in the font) ...