R: Cairographics-based SVG, PDF and PostScript Graphics Devices

cairo {grDevices}

R Documentation

Cairographics-based SVG, PDF and PostScript Graphics Devices

Description

Graphics devices for SVG, PDF and PostScript graphics files using the cairo graphics API.

Usage

svg(filename = if(onefile) "Rplots.svg" else "Rplot%03d.svg",
    width = 7, height = 7, pointsize = 12,
    onefile = FALSE, family = "sans", bg = "white",
    antialias = c("default", "none", "gray", "subpixel"),
    symbolfamily)

cairo_pdf(filename = if(onefile) "Rplots.pdf" else "Rplot%03d.pdf",
          width = 7, height = 7, pointsize = 12,
          onefile = TRUE, family = "sans", bg = "white",
          antialias = c("default", "none", "gray", "subpixel"),
          fallback_resolution = 300, symbolfamily)

cairo_ps(filename = if(onefile) "Rplots.ps" else "Rplot%03d.ps",
         width = 7, height = 7, pointsize = 12,
         onefile = TRUE, family = "sans", bg = "white",
         antialias = c("default", "none", "gray", "subpixel"),
         fallback_resolution = 300, symbolfamily)

Arguments

`filename`	the file path of the output file(s). The page number is substituted if a C integer format is included in the character string, as in the default. (Depending on the platform, the result must be less than `PATH_MAX` characters long, and may be truncated if not. See `pdf` for further details.) Tilde expansion is performed where supported by the platform.
`width`	the width of the device in inches.
`height`	the height of the device in inches.
`pointsize`	the default pointsize of plotted text (in big points).
`onefile`	should all plots appear in one file or in separate files?
`family`	one of the device-independent font families, `"sans"`, `"serif"` and `"mono"`, or a character string specify a font family to be searched for in a system-dependent way. On unix-alikes (incl.\ macOS), see the ‘Cairo fonts’ section in the help for `X11`.
`bg`	the initial background colour: can be overridden by setting `par("bg")`.
`antialias`	string, the type of anti-aliasing (if any) to be used; defaults to `"default"`.
`fallback_resolution`	numeric: the resolution in dpi used when falling back to bitmap output.
`symbolfamily`	a length-one character string that specifies the font family to be used as the "symbol" font (e.g., for plotmath output).

Details

SVG (Scalar Vector Graphics) is a W3C standard for vector graphics. See https://www.w3.org/Graphics/SVG/. The output from svg is SVG version 1.1 for onefile = FALSE (the default), otherwise SVG 1.2. (SVG 1.2 never passed the draft stage. Few SVG viewers are capable of displaying multi-page SVG files, and they have been dropped from SVG 2.0 (still in draft).)

Note that unlike pdf and postscript, cairo_pdf and cairo_ps sometimes record bitmaps and not vector graphics. On the other hand, they can (on suitable platforms) include a much wider range of UTF-8 glyphs, and embed the fonts used.

The output produced by cairo_ps(onefile = FALSE) will be encapsulated postscript on a platform with cairo >= 1.6.

R can be compiled without support for any of these devices: this will be reported if you attempt to use them on a system where they are not supported.

If you plot more than one page on one of these devices and do not include something like %d for the sequence number in filename (or set onefile = TRUE) the file will contain the last page plotted.

There is full support of semi-transparency, but using this is one of the things liable to trigger bitmap output (and will always do so for cairo_ps).

Value

A plot device is opened: nothing is returned to the R interpreter.

Anti-aliasing

Anti-aliasing is applied to both graphics and fonts. It is generally preferable for lines and text, but can lead to undesirable effects for fills, e.g. for image plots, and so is never used for fills.

antialias = "default" is in principle platform-dependent, but seems most often equivalent to antialias = "gray".

Conventions

This section describes the implementation of the conventions for graphics devices set out in the ‘R Internals’ manual.

The default device size is in pixels (svg) or inches.
Font sizes are in big points.
The default font family is Helvetica.
Line widths are multiples of 1/96 inch.
Circle radii have a minimum of 1/72 inch.
Colours are interpreted by the viewing application.

Warning

Support for all these devices are optional, so in packages they should be used conditionally after checking capabilities("cairo").

Note

In principle these devices are independent of X11 (as is seen by their presence on Windows). But on a Unix-alike the cairo libraries may be distributed as part of the X11 system and hence that (for example, on macOS, XQuartz) may need to be installed.