System$findGraphicsDevice
Searches for a working PNG device
Searches for a working PNG device.
On Unix, the png device requires that X11 is available, which it is not
when running batch scripts or running Rremotely. In such cases, an
alternative is to use the bitmap() device, which generates an
EPS file and the uses Ghostscript to transform it to a PNG file.
Moreover, if identical looking bitmap and vector graphics (EPS) files
are wanted for the same figures, in practice, bitmap() has
to be used.
By default, this method tests a list of potential graphical devices and
returns the first that successfully creates an image file.
By default, it tries to create a PNG image file via the built-in
png() device.
Usage
## Static method (use this):
## System$findGraphicsDevice(devices=list(png), maxCount=100, sleepInterval=0.1,
## findGhostscript=TRUE, ...)## Don't use the below:
## S3 method for class 'System':
findGraphicsDevice(static, devices=list(png), maxCount=100, sleepInterval=0.1,
findGhostscript=TRUE, ...)
Arguments
- devices
- A
listof graphics device driverfunctions to be tested. - maxCount
- The maximum number of subsequent tests for the
the existances of
bitmap()generated image files. - sleepInterval
- The time in seconds between above subsequent tests.
- findGhostscript
- If
TRUE, Ghostscript, which is needed by thebitmap()device, is searched for on the current system. If found, its location is recorded. - ...
- Not used.
Value
See Also
For supported graphical devices, see capabilities().
png,
bitmap() and dev2bitmap.
*findGhostscript().
For more information see System.
Examples
fcn <- System$findGraphicsDevice();
if (identical(fcn, png)) {
cat("PNG device found: png()");
} else if (identical(fcn, bitmap)) {
cat("PNG device found: bitmap()");
} else {
cat("PNG device not found.");
}