Geografic-Information-System/display/d.mon/d.mon.html

<h2>DESCRIPTION</h2>

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

<h3>Start a monitor</h3> 

In order to display on-screen GRASS graphics, the user must
<b>start</b> and <b>select</b> a graphics monitor. By default,
the <b>start</b> 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 <b>-l</b> flag on the command
line. Note that some monitor <a href="displaydrivers.html">drivers</a> use environment
<em><a href="variables.html">variables</a></em> or the specific
<em><a href="variables.html#rendering">driver documentation</a></em>.

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

<p>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.

<h3>Stop a monitor</h3> 

A graphics monitor has two different types of status: monitor
program <em>not running</em>, and monitor <em>running</em>. 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 <b>-l</b> flag will list all currently running monitors.

<h3>Select a monitor</h3> 

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

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

<h3>Release a monitor</h3>

Currently <em>selected</em> a monitor can be released by <b>-r</b>
flag.

<h2>EXAMPLES</h2>

To start interactive <em><a href="wxGUI.html">wxGUI</a></em> map
display

<div class="code"><pre>
d.mon start=wx0
</pre></div>

All data will be rendered on <tt>wx0</tt> display. New monitor can be
started (and selected ) by

<div class="code"><pre>
d.mon start=cairo output=out.pdf
</pre></div>

To list running monitors

<div class="code"><pre>
d.mon -l

List of running monitors:
wx0
cairo
</pre></div>

To determine currently selected monitor

<div class="code"><pre>
d.mon -p

cairo
</pre></div>

From this moment all data will be rendered into
file <tt>output.pdf</tt>. To switch back to interactive wxGUI monitor


<div class="code"><pre>
d.mon select=wx0
</pre></div>

To close this monitor

<div class="code"><pre>
d.mon stop=wx0
</pre></div>

<h2>SEE ALSO</h2>

<em>
  <a href="d.erase.html">d.erase</a>,
  <a href="d.redraw.html">d.redraw</a>,
  <a href="d.rast.html">d.rast</a>,
  <a href="d.vect.html">d.vect</a>
</em>

<p>
See also
<em>
list of <a href="variables.html">variables</a>,
<a href="displaydrivers.html">display drivers</a>
</em>

<h2>AUTHOR</h2>

Martin Landa, Czech Republic

<p><i>Last changed: $Date$</i>