Device Handling

The graphics device to be utilised is opened using the command

qcl>OPEN GRP_PDEV

If a device is already open this will be closed first; only one device can be used at a time. OPEN uses the PGPLOT device names syntax. The following names are defined:

For example, to use xw you simply type

qcl>OPEN xw

Strictly the parameter xw should be enclosed in single quotes but providing you don't assign the QCL symbol xw then all will be fine.

If you want to close a device then use the command

qcl>CLOSE

The entire plotting surface of the open device can be cleared using

qcl>CLEAR

For hard copy devices this has the effect of starting with a new piece of paper.

The area or ZONE of the device plotting surface which is used is controlled by

qcl>ZONE GRP_ZLEFT,GRP_ZRIGHT,GRP_ZBOT,GRP_ZTOP

When a device is first opened the zone to be used is set as the entire available surface. The smallest dimension of this surface has size 1.0 and the other is appropriately scaled to give the correct aspect ratio. The normalised dimensions of this surface can be listed using the command:

qcl>.SHOW GRP_Q*

The largest square zone that can be accommodated by the device can be used by issuing the command

qcl>ZONE 0.0,1.0,0.0,1.0

If the device has a square plotting surface then this command is unnecessary. Smaller areas of the surface can be used by subsequent ZONE commands. The parameters always refer to positions in the original complete plotting surface set by the OPEN command.