DESCRIPTION

d.mon allows the user to start, select, list, release, and stop available graphics monitors.

Starting a monitor

In order to display on-screen GRASS graphics, the user must start and select a graphics monitor. By default, the start command actually runs two commands, to both start and select whatever monitor is named by the user. The user can get a list of running monitors by setting the -l flag on the command line. Note that some monitor drivers use environment variables or the specific driver documentation.

When a monitor is started, it is therefore also (automatically) selected for output, unless the -s flag is set by the user; the user can also explicitly select a monitor that has been started.

The desired monitor should be started once and need not be restarted unless it is stopped for some reason. A monitor may continue to run for any length of time, even when no GRASS session is being run.

Stopping a monitor

A graphics monitor has two different types of status: monitor program not running, and monitor running. A monitor that has been started and/or selected will be listed as running; a monitor that has been stopped (or not started) will be listed as not running. The -l flag will list all currently running monitors.

Selecting a monitor

When the user starts a monitor, it is also (automatically) selected for graphics output unless the user sets the -s flag. In order to use (direct graphics output to) a monitor, the user must select that monitor for use, either by simply starting the monitor without the -s flag or by explicitly selecting the monitor for output. Only running monitors can be selected for graphics output.

The user can run multiple graphics monitors by simply starting each of the graphics monitors the user wishes to direct output to.

Releasing (unselecting) a monitor

Currently selected a monitor can be released by -r flag.

NOTES

d.mon is designed for interactive use. If non-interactive use is needed (e.g., in a script) set GRASS_RENDER_IMMEDIATE=png (or =cairo) and use the related environment variables to control output size etc.

EXAMPLES

wx0 monitor

To start interactive wxGUI map display, run 
d.mon start=wx0
All data will be rendered on wx0 display.

CAIRO file renderer monitor

A new CAIRO monitor can be started (and selected) by 
d.mon start=cairo output=out.pdf
From this moment all data will be rendered into file output.pdf.

List running monitors

To list running monitors, use 
d.mon -l

List of running monitors:
wx0
cairo

Show currently selected monitor

To determine currently selected monitor 
d.mon -p

cairo

Switching between monitors

To switch back to interactive, earlier started and still running wxGUI monitor 
d.mon select=wx0

Stopping a monitor

To close the wxGUI monitor 
d.mon stop=wx0

SEE ALSO

d.erase, d.redraw, d.rast, d.vect

See also list of variables for rendering, display drivers

AUTHOR

Martin Landa, OSGeoREL, Czech Technical University in Prague, Czech Republic

Last changed: $Date$