# findGraphicsDevice.System

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##### 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 by first testing the bitmap() device (via png2()) and then the built-in png() device.

Keywords
methods, internal, device
System$findGraphicsDevice(devices=list(png2, png), maxCount=300, sleepInterval=0.1, findGhostscript=TRUE, ...) ##### Arguments devices A list of graphics device driver functions to be tested. maxCount The maximum number of subsequent tests for the the existances of bitmap() generated image files. sleepInterval The time in seconds between above subsequent tests. findGhostscript If TRUE, ghostscript, which is needed by the bitmap() device, is searched for on the current system. If found, its location is recorded. ... Not used. ##### Value • Returns a function that generates images, or NULL. ##### synopsis findGraphicsDevice.System(static, devices=list(png2, png), maxCount=300, sleepInterval=0.1, findGhostscript=TRUE, ...) ##### See Also For supported graphical devices, see capabilities(). png, bitmap() and dev2bitmap. *findGhostscript(). For more information see System. ##### Aliases • findGraphicsDevice.System • System.findGraphicsDevice • findGraphicsDevice.System • findGraphicsDevice,System-method ##### Examples fcn <- System$findGraphicsDevice();
if (identical(fcn, png)) {
cat("PNG device found: png()");
} else if (identical(fcn, png2)) {
cat("PNG device found: png2()");
} else if (identical(fcn, bitmap)) {
cat("PNG device found: bitmap()");
} else {
}