PDF Font Types

Type 1

This was the original outline format created by Adobe along with the Postscript language for printers. The glyph outlines are described using a simplified version of Postscript.

TrueType

Created by Apple and Microsoft for their operating systems, this is the most well known of the font formats. Glyph outlines are described using a special language that is unique to this font format.

OpenType

While Type 1 and TrueType fonts each have their advantages, the industry grew tired of the “font wars,” so OpenType was born. OpenType combines the best of the other formats, with the option of glyph outlines being described either as Type 1 or as TrueType.

For these font types, the actual font program is defined in a separate font file, which may be either embedded in a PDF stream object or obtained from an external source. PDF also has two types of fonts that are specific to PDF, where the glyph data must be defined in the PDF:

Type 3

Originally provided as a way to embed bitmapped fonts, a Type 3 font is really a PDF dictionary where each glyph is defined by a standard content stream. This Fonts allows not only raster-based glyphs, but the use of any/all PDF graphic operators to define the glyph. Although they can be very powerful, they are not used in most PDF-producing systems today.

Type 0

Also known as a composite font or CIDFont, a Type 0 font is created by taking glyph descriptions from one or more other fonts and creating an amalgam or composite. This was originally necessary when working with fonts in Chinese, Japanese, or Korean (CJK) that didn’t also have English/Latin characters and a single font with both was desired. Though not used to actually amalgamate glyphs from multiple fonts, it is still the method used for Unicode fonts, especially when dealing with two-byte data.

A CIDFont program contains glyph descriptions that are accessed using a CID as the character selector. There are two types of CIDFonts:

CIDFontType0 A CIDFont whose glyph descriptions are based on Type 1 font technology.

CIDFontType2 A CIDFont whose glyph descriptions are based on TrueType font technology.