macOS Quartz Device

Description

quartz starts a graphics device driver for the macOS System. It supports plotting both to the screen (the default) and to various graphics file formats.

Usage

quartz(title, width, height, pointsize, family, antialias, type,
      file = NULL, bg, canvas, dpi)

quartz.options(..., reset = FALSE)

quartz.save(file, type = "png", device = dev.cur(), dpi = 100, ...)

Arguments

Details

The defaults for all but one of the arguments of quartz are set by quartz.options: the ‘Arguments’ section gives the ‘factory-fresh’ defaults.

The Quartz graphics device supports a variety of output types. On-screen output types are "" or "native" or "Cocoa". Off-screen output types produce output files and utilize the file argument. type = "pdf" gives PDF output. The following bitmap formats may be supported (depending on the OS version): "png", "jpeg", "jpg", "jpeg2000", "tif", "tiff", "gif", "psd" (Adobe Photoshop), "bmp" (Windows bitmap), "sgi" and "pict".

The file argument is used for off-screen drawing. The actual file is only created when the device is closed (e.g., using dev.off()). For the bitmap devices, the page number is substituted if a C integer format is included in the character string, e.g. Rplot%03d.png. (The result must be less than PATH_MAX characters long, and may be truncated if not. See postscript for further details.) If a file argument is not supplied, the default is Rplots.pdf or Rplot%03d.type. Tilde expansion (see path.expand) is done.

If a device-independent R graphics font family is specified (e.g., via par(family =) in the graphics package), the Quartz device makes use of the Quartz font database (see quartzFonts) to convert the R graphics font family to a Quartz-specific font family description. The default conversions are (MonoType TrueType versions of) Helvetica for sans, Times-Roman for serif and Courier for mono.

On-screen devices are launched with a semi-transparent canvas. Once a new plot is created, the canvas is first painted with the canvas colour and then the current background colour (which can be transparent or semi-transparent). Off-screen devices have no canvas colour, and so start with a transparent background where possible (e.g., type = "png" and type = "tiff") – otherwise it appears that a solid white canvas is assumed in the Quartz code. PNG and TIFF files are saved with a dark grey matte which will show up in some viewers, including Preview.

title can be used for on-screen output. It must be a single character string with an optional integer printf-style format that will be substituted by the device number. It is also optionally used (without a format) to give a title to a PDF file.

Calling quartz() sets .Device to "quartz" for on-screen devices and to "quartz_off_screen" otherwise.

The font family chosen needs to cover the characters to be used: characters not in the font are rendered as empty oblongs. For non-Western-European languages something other than the default of "Arial" is likely to be needed—one choice for Chinese is "MingLiU".

quartz.save is a modified version of dev.copy2pdf to copy the plot from the current screen device to a quartz device, by default to a PNG file.

Conventions

This section describes the implementation of the conventions for graphics devices set out in the “R Internals Manual”.

• The default device size is 7 inches square.

• Font sizes are in big points.

• The default font family is Arial.

• Line widths are a multiple of 1/96 inch with no minimum set by R.

• Circle radii are real-valued with no minimum set by R.

• Colours are specified as sRGB.

Note

For a long time the default font family was documented as "Helvetica" after it had been changed to "Arial" to work around a deficiency in macOS 10.4. It may be changed back in future.

A fairly common Mac problem is no text appearing on plots due to corrupted or duplicated fonts on your system. You may be able to confirm this by using another font family, e.g. family = "serif". Open the Font Book application (in Applications) and check the fonts that you are using.

See Also

quartzFonts, Devices.

png for way to access the bitmap types of this device via R's standard bitmap devices.

Examples

## Not run: 
## put something like this is your .Rprofile to customize the defaults
setHook(packageEvent("grDevices", "onLoad"),
        function(...) grDevices::quartz.options(width = 8, height = 6,
                                                pointsize = 10))

## End(Not run)