file type: only "png" will be accepted for cairo
version 1.0.
device
the device to save from.
Details
Only cairo-based X11 devices are supported.
This works by copying the image surface to a file. For PNG
will always be a 24-bit per pixel PNG ‘DirectClass’ file, for
JPEG the quality is 75% and for TIFF there is no compression.
For devices with buffering this copies the buffer's image surface, so
works even if dev.hold has been called.
At present the plot is saved after rendering onto the canvas (default
opaque white), so for the default bg = "transparent" the
effective background colour is the canvas colour.
Value
Invisible NULL.
Note
There is a similar function of the same name but more types for
windows devices on Windows.