Graphics Programs Reference
In-Depth Information
There are 14 standard Type 1 fonts in PDF. These are fonts where the metrics and
outlines (or suitable substitution fonts) must be available in any PDF application.
Nowadays, however, Adobe recommends that all fonts are fully embedded, even these.
The standard fonts are:
Times-Roman
Times-Bold
Times-Italic
Times-BoldItalic
Helvetica
Helvetica-Bold
Helvetica-Oblique
Helvetica-BoldOblique
Courier
Courier-Bold
Courier-Oblique
Courier-BoldOblique
Symbol
ZapfDingbats
For example, here is a simple Type 1 font:
1 0 obj
<< /Type /Font
/Subtype /Type1
/BaseFont /Times-Roman
/FirstChar 0
/LastChar 255
/Widths [ 255 255 255 255 ... 744 268 380 380 380 380 380 380 380 380 380 380 ]
/FontDescriptor 2 0 R
/Encoding /WinAnsiEncoding
>>
The ellipsis
...
is content we have omitted, not part of the PDF language. We discuss
the
/FontDescriptor
and
/Encoding
entries later. The
/Widths
array gives the widths in
thousandths of a text space unit for each of the 256 characters in this font.
Font Encodings
The
font encoding
describes the mapping between character codes (characters in the
strings used in content streams) and glyph descriptions in the font. Font programs have
their own built-in encodings, but the PDF font can alter the encoding to use a Macintosh
font with a Microsoft Windows encoding, or to use a single-byte encoding to select up
to 256 characters from a font with more than 256 glyphs (e.g., variations on characters
or ligatures).
The simplest
/Encoding
entry is just the name of one of the standard encodings, which
are defined in the PDF Standard, Appendix D. More complicated encodings are defined
