R: Check for changes in the graphics state of Cairo devices.
Cairo.serial
R Documentation
Check for changes in the graphics state of Cairo devices.
Description
Cairo.serial returns an integer that is increased with every
plotting operation on the device. This allows user code to determine
whether any new content has been added to the device since it was last
checked.
Usage
Cairo.serial(device = dev.cur())
Arguments
device
device number or an object of the class Cairo (as
obtained from the Cairo function).
Value
Integer value.
Note
The integer value overflows to 0 at 2^31. Typically only equality
should be checked and for such it is extremely unlikely that the state
has changed yet the serial value is the same due to overflow.