getLatexStrWidth: Obtain Font Metrics from LaTeX

In tikzDevice: R Graphics Output in LaTeX Format

Description

These functions calculate the width of a character or string as it would appear after being compiled by LaTeX.

Usage

  getLatexStrWidth(texString, cex = 1, face = 1,
    engine = getOption("tikzDefaultEngine"),
    documentDeclaration = getOption("tikzDocumentDeclaration"),
    packages)

  getLatexCharMetrics(charCode, cex = 1, face = 1,
    engine = getOption("tikzDefaultEngine"),
    documentDeclaration = getOption("tikzDocumentDeclaration"),
    packages)

Arguments

texString	An arbitrary string for which the width is to be calculated. May contain LaTeX markup.
cex	a real number that specifies a scaling factor that is to be applied to device output.
face	an integer in the range [1-5] that specifies the font face to use. See par for details.
engine	a string specifying which TeX engine to use. Possible values are 'pdftex', 'xetex' and 'luatex'. See the Unicode section of tikzDevice for details.
documentDeclaration	See the sections “Options That Affect Package Behavior” and “Font Size Calculations” of tikzDevice-package for more details.
packages	See the section “Options That Affect Package Behavior” of tikzDevice-package.
charCode	an integer that corresponds to a symbol in the ASCII character table under the Type 1 font encoding. All numeric values are coerced using as.integer. Non-numeric values will not be accepted.

Details

These functions are used internally by the tikz device for proper string placement in graphics. Both functions check to see if metrics exist in a global or temporary dictionary (as defined in options('tikzMetricsDictionary')) and if so will pull the metrics from there. If the dictionary does not exist, then a temporary one is created for the current R session. Metrics are calculated via system calls to LaTeX compilers. Querying compilers to calculate metrics is expensive and so we strongly recommend setting options('tikzMetricsDictionary') <- /path/to/dictionary to create a global dictionary.

Value

getLatexStrWidth	The width of texString in points.
getLatexCharMetrics	A numeric vector holding ascent, descent and width. Values should all be nonnegative.

Author(s)

Charlie Sharpsteen [e-mail] and Cameron Bracken [e-mail]

References

PGF Manual

Examples

getLatexStrWidth('{\\\\tiny Hello \\\\LaTeX!}')
# Calculate ascent, descent and width for "A"
  getLatexCharMetrics(65)

tikzDevice documentation built on May 2, 2019, 4:50 p.m.