NAME

       PDL::Graphics::PGPLOT - PGPLOT enhanced interface for PDL

SYNOPSIS

        pdl> $a = pdl [1..100]
        pdl> $b = sqrt($a)
        pdl> line $b
        pdl> hold
        Graphics on HOLD
        pdl> $c = sin($a/10)*2 + 4
        pdl> line $c

DESCRIPTION

       "PDL::Graphics::PGPLOT" is a convenience interface to the PGPLOT commands, implemented
       using the object oriented PGPLOT plotting package in PDL::Graphics::PGPLOT::Window. See
       the documentation for that package for in-depth information about the usage of these
       commands and the options they accept.

       The list of currently availably commands:

        imag       -  Display an image (uses pgimag()/pggray() as appropriate)
        im         -  Shorthand to display an image with aspect ratio of 1
        fits_imag  -  Display a FITS image with appropriate transforms & labels
        cont       -  Display image as contour map
        fits_cont  -  Display a FITS image in scientific coordinates as a contour map
        vect       -  Display 2 images as a vector field
        fits_vect  -  Display 2 FITS images in sci. coordinates as a vector field
        ctab       -  Load an image colour table
        ctab_info  -  Get information about currently loaded colour table
        line       -  Plot vector as connected points
        points     -  Plot vector as points
        errb       -  Plot error bars
        bin        -  Plot vector as histogram (e.g. bin(hist($data)) )
        hi2d       -  Plot image as 2d histogram (not very good IMHO...)
        poly       -  Draw a polygon
        text       -  Write text in the plot area
        label_axes -  Print axis titles
        legend     -  Create a legend with different texts, linestyles etc.
        cursor     -  Interactively read cursor positions.
        circle     -  Draw a circle
        ellipse    -  Draw an ellipse.

       Device manipulation commands:

        hold         -  Hold current plot window range - allows overlays etc.
        release      -  Release back to autoscaling of new plot window for each
                        command
        rel          -  short alias for 'release'
        env          -  Define a plot window, put on 'hold'
        dev          -  Explicitly set a new PGPLOT graphics device
        new_window   -  Create a new plot window (use of dev is recommended)
        focus_window -  Change focus to a new window
        window_list  -  Get a list of currently existing plot windows
        close_window -  Close an open window

FUNCTIONS

       The following is a list of the functions that are private to this package, for the other
       functions please read the PDL::Graphics::PGPLOT::Window documentation.

   dev
       Open PGPLOT graphics device

        Usage: dev $device, [$nx,$ny, $opt];

       $device is a PGPLOT graphics device such as "/xserve" or "/ps", if omitted defaults to
       last used device (or value of env var "PGPLOT_DEV" if first time).  $nx, $ny specify sub-
       panelling. The function returns the id of the newly created window - this can subsequently
       be used as argument to "focus_window" to select the window.

       The result of this command can be modified using options. The options recognised are the
       same as for "new_window" - which primarily and in addition it is possible to set the
       default values for a window that are defined in PDL::Graphics::PGPLOTOptions, see this for
       details but see below for a synopsis.

       In addition "dev" recognises the option "NewWindow" which allows the user to specify that
       a "dev" command is to create a new window rather than closing the previous. This allows a
       large number of output destinations to be open at the same time, which occasionally can be
       convenient.

       Here is a quick summary of the most useful additional options that can be given:

       Device
           Alternative to $device.

       AspectRatio
           The aspect ratio of the output window

       WindowWidth
           The width of the plot window in inches

       AxisColour
           The axis colour to be used as default for plots in this window. In the same way it is
           possible to set the default character size ("CharSize") and axis and box styles. See
           PDL::Graphics::PGPLOTOptions for details.

       WindowName
           The name of a window. This name can subsequently be used to refer to the window
           instead of its ID, making interactive use somewhat more intuitive.

       To open a X-window output that will stay on screen:

         $win = dev('/xs');

       To open two windows, one small and square, one large and wide:

         $win1 = dev('/xs', {Aspect => 1, WindowWidth => 4});
         $win2 = dev('/xs', {Aspect => 0.5, WindowWidth => 10});

   new_window
       Open a PGPLOT graphics device

         $win = new_window($dev, $nx, $ny, $opt);

       This function is identical to dev except that it always creates a new window. This means
       that the user is required to close all windows explicitly using close_window. All
       functionality is otherwise like "dev" so see the documentation for dev for details of use.

   close_window
       Close a PGPLOT output device

        Usage: close_window($id)

       This function closes a PGPLOT output device created with "dev" or "new_window". It
       requires the id of the window to close. If $id is left undefined, the currently focussed
       window is deleted and focus is transferred to the lowest numbered window in existence. If
       many windows have been created and deleted this might not be what you expect, so it is
       recommended to make an explicit call to focus_window after any call to "close_window".

   _get_windownumber
       Internal function to obtain the ID of a window. This allows the user to refer to a window
       with its name.

   focus_window
       Switch to another output window.

        Usage: focus_window($id);

       This command is used to switch output focus to another window created by dev or
       new_window. The window can be referred to either by its ID or by its name.

         $win1 = dev('/xs', {WindowName => 'X-output'});
         $win2 = dev('test.ps/ps', {WindowName => 'PS-output'});

         focus_window('X-output');  # Or focus_window($win1);
         <.. Commands ..>
         focus_window($win2);       # Or focus_window('PS-output');
         <.. Commands ..>

   window_list
       Return a list of ID numbers and names of the windows currently opened using dev or
       new_window.

        Usage: ($numbers, $names)=window_list();

       $numbers and $names are anonymous arrays giving the ID numbers and names of the open
       windows respectively.