DESCRIPTION

C-PLOT graphics filters are separate programs through which the C-PLOT plotting program sends instructions that describe the graphics to be produced. Each graphic filter takes those instructions and produces code for a particular type of display device. Graphics filters exist for printers, video terminals and workstations.

Installed filters reside in the directory $CPLOTHOME/filters. Tools for making additional filters reside in $CPLOTHOME/filters_tools.

When running C-PLOT, a graphics filter must be chosen before the z commands will do any drawing. The zi command is used to select and initialize the filter. If you haven't selected a filter before you use one of the z drawing commands, you will be prompted for the filter name, as if you had entered the zi command. Without arguments the zi command will list the filters available in $CPLOTHOME/filters.

When entering the filter name, you also can enter arguments to specify an output file, a printer spooler command or various device modes. Which of these arguments are relevant depends on the particular filter. Giving a file or device name as the first argument after the filter name will cause the standard output of the filter to be redirected there. See the zi help file for more information on filter arguments.

When using graphics filter commands to draw the plot, you must enter a second <return> to get back to the PLOT-> prompt, even if you are using a printer filter. On video terminals, the second <return> returns the terminal to text mode.

When using C-PLOT filters that send output to a printer, you must first issue the zw command to stop the filter from printing a page for each plot element that you add with successive z commands. When you have added all the elements to the plot, use the zs command to complete the plot. See the zw and zs help files for more information.