bitmap generates a graphics file.
dev2bitmap copies the current graphics device to a file in a
graphics format.
bitmap(file, type = "png16m", height = 7, width = 7, res = 72,
units = "in", pointsize, taa = NA, gaa = NA, …)dev2bitmap(file, type = "png16m", height = 7, width = 7, res = 72,
units = "in", pointsize, …,
method = c("postscript", "pdf"), taa = NA, gaa = NA)
The output file name, with an appropriate extension.
The type of bitmap.
Dimensions of the display region.
Resolution, in dots per inch.
The units in which height and width are
given. Can be in (inches), px (pixels), cm or
mm.
The pointsize to be used for text: defaults to something reasonable given the width and height
Other parameters passed to postscript or
pdf.
Should the plot be done by postscript or
pdf?
Number of bits of antialiasing for text and for graphics respectively. Usually 4 (for best effect) or 2. Not supported on all types.
None.
This section describes the implementation of the conventions for
graphics devices set out in the “R Internals Manual”. These
devices follow the underlying device, so when viewed at the stated
res:
The default device size is 7 inches square.
Font sizes are in big points.
The default font family is (for the standard Ghostscript setup) URW Nimbus Sans.
Line widths are as a multiple of 1/96 inch, with no minimum.
Circle of any radius are allowed.
Colours are interpreted by the viewing/printing application.
dev2bitmap works by copying the current device to a
postscript or pdf device, and
post-processing the output file using ghostscript.
bitmap works in the same way using a postscript device
and post-processing the output as ‘printing’.
You will need ghostscript: the full path to the executable can
be set by the environment variable R_GSCMD. If this is unset, a
GhostScript executable will be looked for by name on your path: on a
Unix alike "gs" is used, and on Windows the setting of the
environment variable GSC is used, otherwise commands
"gswi64c.exe" then "gswin32c.exe" are tried.
The types available will depend on the version of ghostscript,
but are likely to include
"jpeg", "jpegcmyk", "jpeggray",
"tiffcrle", "tiffg3",
"tiffg32d", "tiffg4", "tiffgray", "tifflzw",
"tiffpack", "tiff12nc", "tiff24nc", "tiff32nc"
"png16", "png16m", "png256", "png48",
"pngmono", "pnggray", "pngalpha",
"bmp16", "bmp16m" "bmp256", "bmp32b",
"bmpgray", "bmpmono".
The default type, "png16m", supports 24-bit colour and
anti-aliasing. Type "png256" uses a palette of 256 colours and
could give a more compact representation. Monochrome graphs can use
"pngmono", or "pnggray" if anti-aliasing is desired.
Plots with a transparent background and varying degrees of
transparency should use "pngalpha".
Note that for a colour TIFF image you probably want "tiff24nc",
which is 8-bit per channel RGB (the most common TIFF format). None of
the listed TIFF types support transparency. "tiff32nc" uses
8-bit per channel CMYK, which printers might require.
For formats which contain a single image, a file specification like
Rplots%03d.png can be used: this is interpreted by Ghostscript.
For dev2bitmap if just one of width and height is
specified, the other is chosen to preserve the aspect ratio of the
device being copied. The main reason to prefer method = "pdf"
over the default would be to allow semi-transparent colours to be used.
For graphics parameters such as "cra" that need to work in
pixels, the default resolution of 72dpi is always used.
On Windows only,
paths for file and R_GSCMD which contain spaces are
mapped to short names via shortPathName.
savePlot, which for windows and
X11(type = "cairo") provides a simple way to record a PNG
record of the current plot.
postscript, pdf, png,
jpeg, tiff and bmp.
To display an array of data, see image.