Type1Font: Type 1 and CID Fonts

Description

These functions are used to define the translation of a R graphics font family name to a Type 1 or CID font descriptions, used by both the postscript and pdf graphics devices.

Usage

Type1Font(family, metrics, encoding = "default")
CIDFont(family, cmap, cmapEncoding, pdfresource = "")

Arguments

family

a character string giving the name to be used internally for a Type 1 or CID-keyed font family. This needs to uniquely identify each family, so if you modify a family which is in use (see postscriptFonts) you need to change the family name.

metrics

a character vector of four or five strings giving paths to the afm (Adobe Font Metric) files for the font.

cmap

the name of a CMap file for a CID-keyed font.

encoding

for Type1Font, the name of an encoding file. Defaults to "default", which maps on Unix-alikes to "ISOLatin1.enc" and on Windows to "WinAnsi.enc". Otherwise, a file name in the ‘enc’ directory of the grDevices package, which is used if the path does not contain a path separator. An extension ".enc" can be omitted.

cmapEncoding

The name of a character encoding to be used with the named CMap file: strings will be translated to this encoding when written to the file.

pdfresource

A chunk of PDF code; only required for using a CID-keyed font on pdf; users should not be expected to provide this.

Value

A list of class "Type1Font" or "CIDFont".

Details

For Type1Fonts, if four ‘.afm’ files are supplied the fifth is taken to be "Symbol.afm". Relative paths are taken relative to the directory ‘R_HOME/library/grDevices/afm’. The fifth (symbol) font must be in AdobeSym encoding. However, the glyphs in the first four fonts are referenced by name and any encoding given within the ‘.afm’ files is not used.

The ‘.afm’ files may be compressed with (or without) final extension ‘.gz’: the files which ship with R are installed as compressed files with this extension.

Glyphs in CID-keyed fonts are accessed by ID (number) and not by name. The CMap file maps encoded strings (usually in a MBCS) to IDs, so cmap and cmapEncoding specifications must match. There are no real bold or italic versions of CID fonts (bold/italic were very rarely used in traditional East Asian topography), and for the pdf device all four font faces will be identical. However, for the postscript device, bold and italic (and bold italic) are emulated.

CID-keyed fonts are intended only for use for the glyphs of East Asian languages, which are all monospaced and are all treated as filling the same bounding box. (Thus plotmath will work with such characters, but the spacing will be less carefully controlled than with Western glyphs.) The CID-keyed fonts do contain other characters, including a Latin alphabet: non-East-Asian glyphs are regarded as monospaced with half the width of East Asian glyphs. This is often the case, but sometimes Latin glyphs designed for proportional spacing are used (and may look odd). We strongly recommend that CID-keyed fonts are only used for East Asian glyphs.

Examples

Run this code

## This duplicates "ComputerModernItalic".
CMitalic <- Type1Font("ComputerModern2",
                      c("CM_regular_10.afm", "CM_boldx_10.afm",
                        "cmti10.afm", "cmbxti10.afm",
                        "CM_symbol_10.afm"),
                      encoding = "TeXtext.enc")

## Not run: 
# ## This could be used by
# postscript(family = CMitalic)
# ## or
# postscriptFonts(CMitalic = CMitalic)  # once in a session
# postscript(family = "CMitalic", encoding = "TeXtext.enc")
# ## End(Not run)

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