Saves information from the last plot on a particular device.
DKEEP provides information that can be used in general programs and procedures to control the graphical output. For the specified device you can determine whether it generates screen output or uses a file, whether graphical input is possible, a description of the device, the current ENDACTION setting, and details of the axis bounds.
The device for which the information is required is specified by the DEVICE parameter. If you specify a scalar containing a missing value, this will be set to the number of the current graphics device. You can then test whether an output file is needed and open one accordingly.
When writing a procedure you can find out if axes bounds have been set explicitly, using the SAVE parameter of XAXIS, YAXIS and ZAXIS. This information may then be used when setting up the axes for other graphs. However, if the bounds were not set, but have been evaluated from the data (or if the axes have subsequently been redefined) the information in the save structure will not be of any use. The actual values used when plotting are recorded internally, for each window of each device, and can be accessed using the YLOWER, YUPPER, XLOWER and XUPPER parameters of DKEEP.
Parameters: DEVICE, WINDOW, YLOWER, YUPPER, XLOWER, XUPPER, FILE, DESCRIPTION, DREAD, ENDACTION.
Directives: DEVICE, DLOAD, DSAVE, XAXIS, YAXIS, ZAXIS, PEN.