NAME¶
Graphics::GnuplotIF - A dynamic Perl interface to gnuplot
VERSION¶
This documentation refers to Graphics::GnuplotIF version 1.5
SYNOPSIS¶
use Graphics::GnuplotIF qw(GnuplotIF);
my @x = ( -2, -1.50, -1, -0.50, 0, 0.50, 1, 1.50, 2 ); # x values
my @y1 = ( 4, 2.25, 1, 0.25, 0, 0.25, 1, 2.25, 4 ); # function 1
my @y2 = ( 2, 0.25, -1, -1.75, -2, -1.75, -1, 0.25, 2 ); # function 2
my $plot1 = Graphics::GnuplotIF->new(title => "line", style => "points");
$plot1->gnuplot_plot_y( \@x ); # plot 9 points over 0..8
$plot1->gnuplot_pause( ); # hit RETURN to continue
$plot1->gnuplot_set_title( "parabola" ); # new title
$plot1->gnuplot_set_style( "lines" ); # new line style
$plot1->gnuplot_plot_xy( \@x, \@y1, \@y2 ); # plot 1: y1, y2 over x
$plot1->gnuplot_plot_many( \@x, \@y1, \@x, \@y2 ); # plot 1: y1 - x, y2 - x
my $plot2 = Graphics::GnuplotIF->new; # new plot object
$plot2->gnuplot_set_xrange( 0, 4 ); # set x range
$plot2->gnuplot_set_yrange( -2, 2 ); # set y range
$plot2->gnuplot_cmd( "set grid" ); # send a gnuplot command
$plot2->gnuplot_plot_equation( # 3 equations in one plot
"y1(x) = sin(x)",
"y2(x) = cos(x)",
"y3(x) = sin(x)/x" );
$plot2->gnuplot_pause( ); # hit RETURN to continue
$plot2->gnuplot_plot_equation( # rewrite plot 2
"y4(x) = 2*exp(-x)*sin(4*x)" );
$plot2->gnuplot_pause( ); # hit RETURN to continue
my $plot3 = GnuplotIF; # new plot object
my @xyz = ( # 2-D-matrix, z-values
[0, 1, 4, 9],
[1, 2, 6, 15],
[4, 6, 12, 27],
[9, 15, 27, 54],
);
$plot3->gnuplot_cmd( "set grid" ); # send a gnuplot command
$plot3->gnuplot_set_plot_titles("surface"); # set legend
$plot3->gnuplot_plot_3d( \@xyz ); # start 3-D-plot
$plot3->gnuplot_pause( ); # hit RETURN to continue
DESCRIPTION¶
Graphics::GnuplotIF is a simple and easy to use dynamic Perl interface to
gnuplot.
gnuplot is a freely available, command-driven graphical
display tool for Unix. It compiles and works quite well on a number of Unix
flavours as well as other operating systems.
This module enables sending display requests asynchronously to
gnuplot
through simple Perl subroutine calls.
A gnuplot session is an instance of class Graphics::GnuplotIF. The constructor
starts
gnuplot as a separate process for each session. The plot
commands are send through a
pipe. The graphical output from
gnuplot will be displayed immediately.
Several independent plots can be started from one script. Each plot has its own
pipe. All pipes will be closed automatically by the destructor when the script
terminates. The
gnuplot processes terminate when the corresponding
pipes are closed. Their graphical output will now disappear (but see parameter
persist).
Graphics::GnuplotIF is similar to " gnuplot_i ", a C interface to
gnuplot (
http://ndevilla.free.fr/gnuplot/ ), and to " gnuplot_i++
", a C++ interface to
gnuplot (
http://jijo.cjb.net/code/cc++ ).
SUBROUTINES/METHODS¶
An object of this class represents an interface to a running
gnuplot
process. During the creation of an object such an process will be started for
each such object. Communication is done through an unidirectional pipe; the
resulting stream is write-only.
Most methods return a reference to the Graphics::GnuplotIF object, allowing
method calls to be chained like so:
$plot1 -> gnuplot_plot_xy(\@x, \@y)
-> gnuplot_reset;
The exception to this are "gnuplot_get_plotnumber" and
"gnuplot_get_object_id", which are used to obtain specific scalar
values.
new¶
The constructor creates a new
gnuplot session object, referenced by a
handle:
$plot1 = Graphics::GnuplotIF->new( );
A few named arguments can be passed as key - value pairs (here shown with their
default values):
style => 'lines', # one of the gnuplot line styles (see below)
title => '', # string
xlabel => 'x', # string
ylabel => 'y', # string
xrange => [], # array reference; autoscaling, if empty
xrange => [], # array reference; autoscaling, if empty
plot_titles => [], # array of strings; titles used in the legend
scriptfile => '', # write all plot commands to the specified file
plot_also => 0, # write all plot commands to the specified file,
# in addition show the plots
persist => 0, # let plot windows survive after gnuplot exits
# 0 : close / 1 : survive
objectname => '', # an optional name for the object
silent_pause => 1, # 0 suppress message from gnuplot_pause()
These attributes are stored in each object.
Allowed line styles are
boxes dots filledcurves fsteps histeps
impulses lines linespoints points steps
The generated
gnuplot commands can be stored to a file instead of beeing
executed immediately. This file can be used as input to
gnuplot, e.g.
gnuplot < function_set_1.gnuplot
A script file can also be used for checking the commands send to
gnuplot.
The objects are automatically deleted by a destructor. The destructor closes the
pipe to the
gnuplot process belonging to that object. The
gnuplot process will also terminate and remove the graphic output. The
termination can be controlled by the method "gnuplot_pause" .
GnuplotIF¶
The short form of the constructor above ("new"):
use Graphics::GnuplotIF qw(GnuplotIF);
$plot1 = GnuplotIF;
This subroutine is exported only on request.
gnuplot_plot_y¶
$plot1->gnuplot_plot_y( \@y1, \@y2 );
"gnuplot_plot_y" takes one or more array references and plots the
values over the x-values 0, 1, 2, 3, ...
gnuplot_plot_xy¶
$plot1->gnuplot_plot_xy( \@x, \@y1, \@y2 );
"gnuplot_plot_xy" takes two or more array references. The first array
is assumed to contain the x-values for the following function values.
gnuplot_plot_xy_style¶
%y1 = ( 'y_values' => \@y1, 'style_spec' => "lines lw 3" );
%y2 = ( 'y_values' => \@y2,
'style_spec' => "points pointtype 4 pointsize 5" );
$plot1->gnuplot_plot_xy_style( \@x, \%y1, \%y2 );
"gnuplot_plot_xy_style" takes one array reference and one or more hash
references. The first array is assumed to contain the x-values for the
following function values. The following hashes are assumed to contain pairs
of y-values and individual style specifications for use in the plot command.
The 'style_spec' settings are placed between "with" and
"title" of
gnuplot's "plot" command.
gnuplot_plot_many¶
$plot1->gnuplot_plot_xy( \@x1, \@y1, \@x2, \@y2 );
"gnuplot_plot_many" takes pairs of array references. Each pair
represents a function and is a reference to the arrays of x- and y-values for
that function.
gnuplot_plot_many_style¶
%f1 = ( 'x_values' => \@x1, 'y_values' => \@y1,
'style_spec' => "lines lw 3" );
%f2 = ( 'x_values' => \@x2, 'y_values' => \@y2,
'style_spec' => "points pointtype 4 pointsize 5" );
$plot1->gnuplot_plot_many_style( \%f1, \%f2 );
"gnuplot_plot_many_style" takes one or more hash references. The
hashes are assumed to contain array referenses to x-values and y-values and
individual style specifications for use in the plot command. The 'style_spec'
settings are placed between "with" and "title" of
gnuplot's "plot" command.
gnuplot_plot_equation¶
$plot2->gnuplot_plot_equation( # 3 equations in one plot
"y1(x) = sin(x)",
"y2(x) = cos(x)",
"y3(x) = sin(x)/x" );
"gnuplot_plot_equation" takes one or more
gnuplot function
descriptions as strings. The plot ranges can be controlled by
"gnuplot_set_xrange" and "gnuplot_set_yrange" .
gnuplot_plot_3d¶
$plot2->gnuplot_plot_3d( \@array ); # 3-D-plot
"gnuplot_plot_3d" takes one reference to an 2-D-array of z-values.
gnuplot_pause¶
$plot1->gnuplot_pause( [time] [,text] );
This is an emulation of the
gnuplot "pause" command. It
displays any text associated with the command and waits a specified amount of
time or until the carriage return is pressed. The message can be suppressed by
silent_pause => 0
given to the constructor (see new ).
"time" may be any constant or expression. Choosing 0 (default) will
wait until a carriage return is hit, a negative value won't pause at all, and
a positive number will wait the specified number of seconds.
The time value and the text are stored in the object and reused. A sequence like
$plot1->gnuplot_plot_y( \@y1 );
$plot1->gnuplot_pause( 5.5 ); # delay is 5.5 seconds
$plot1->gnuplot_plot_y( \@y2 );
$plot1->gnuplot_pause( );
$plot1->gnuplot_plot_y( \@y3 );
$plot1->gnuplot_pause( );
will display 3 plots with 5.5 seconds delay.
gnuplot_cmd¶
$plot2->gnuplot_cmd( 'set grid',
'set timestamp "%d/%m/%y %H:%M" 0,0 "Helvetica"'
);
"gnuplot_cmd" can be used to send one or more
gnuplot commands,
especially those not wrapped by a Graphics::GnuplotIF method.
gnuplot_reset¶
$plot1->gnuplot_reset();
Set all options set with the "set" command to their
gnuplot
default values.
gnuplot_set_style¶
$plot1->gnuplot_set_style( "steps" ); # new line style
Sets one of the allowed line styles (see new ) in a plot command.
gnuplot_set_title¶
$plot1->gnuplot_set_title("parabola"); # new title
Sets the plot title. Equivalent to the
gnuplot command "set title
"parabola"".
gnuplot_set_xlabel¶
$plot1->gnuplot_set_xlabel("time (days)");
Sets the x axis label. Equivalent to the
gnuplot command "set xlabel
"time (days)"".
gnuplot_set_ylabel¶
$plot1->gnuplot_set_ylabel("bugs fixed");
Sets the y axis label. Equivalent to the
gnuplot command "set ylabel
"bugs fixed"".
gnuplot_set_xrange¶
$plot1->gnuplot_set_xrange( left, right );
Sets the horizontal range that will be displayed. Equivalent to the
gnuplot command "set xrange [left:right]".
gnuplot_set_yrange¶
$plot1->gnuplot_set_yrange( low, high );
Sets the vertical range that will be displayed. Equivalent to the
gnuplot
command "set yrange [low:high]".
gnuplot_set_plot_titles¶
$plot1->gnuplot_set_plot_titles( @ytitles );
Sets the list of titles used in the key for each of the y-coordinate data sets
specified in subsequent calls to gnuplot_plot_xy or gnuplot_plot_y commands.
This is not equivalent to a complete
gnuplot command; rather it adds a
"title" clause to each data set specified in a
gnuplot
"plot" command.
gnuplot_hardcopy¶
"gnuplot_cmd" can be used to write a plot into a file or make a
printable file by setting/resetting the terminal and the output file:
$plot1->gnuplot_hardcopy( 'function1.gnuplot.ps',
'postscript',
'color lw 3' );
$plot1->gnuplot_plot_xy( \@x, \@y1, \@y2 );
$plot1->gnuplot_restore_terminal();
The 1. parameter is a file name, the 2. parameter is a
gnuplot terminal
type, the 3. parameter is a string with additional terminal parameters
(optional). The current terminal settings will be saved.
gnuplot_restore_terminal¶
Restores the saved terminal settings after a call to
"gnuplot_hardcopy()". Output will go to "STDOUT" again.
Print a plot directly
A hardcopy can be made with an appropriate output format and a pipe to a
printer:
$plot1->gnuplot_cmd( 'set terminal postscript',
'set output " | lpr " ' );
$plot1->gnuplot_plot_xy( \@x, \@y1, \@y2 );
$plot1->gnuplot_cmd( 'set output',
'set terminal x11' );
gnuplot_get_object_id¶
Get the (internal) object number (and the object name):
$obj_number = $plot1->gnuplot_get_object_id();
($obj_number, $obj_name) = $plot1->gnuplot_get_object_id();
The object number is set automatically by the constructor. The object name can
be set by the constructor (objectname => 'MyName').
gnuplot_get_plotnumber¶
Get the (internal) plot number of the
next plot:
$plot_number = $plot1->gnuplot_get_plotnumber()
The plot number is set automatically by the constructor starting with 1. Each
call to
gnuplot_plot_y
gnuplot_plot_xy
gnuplot_plot_xy_style
gnuplot_plot_many
gnuplot_plot_many_style
gnuplot_plot_equation
gnuplot_plot_3d
increments this number by 1. This can be used to identify single plots, e.g.
with
$plot->gnuplot_cmd( "set timestamp \"plot number ${plot_number} / %c\"" );
EXPORTS¶
GnuplotIF constructor, short form (see "GnuplotIF" ).
DIAGNOSTICS¶
Dialog messages and diagnostic messages start with " Graphics::GnuplotIF
(object NR): ... " .
"NR" is the number of the corresponding Graphics::GnuplotIF object and
output stream. NR counts the objects in the order of their generation.
The gnuplot messages going to STDERR will be redirected to the file
".gnuplot.PPP.OOO.stderr.log". PPP is the process number, OOO is the
number of the plot object (see "gnuplot_get_object_id").
CONFIGURATION AND ENVIRONMENT¶
The environment variable DISPLAY is checked for the display.
DEPENDENCIES¶
- •
- "gnuplot" ( http://sourceforge.net/projects/gnuplot ) must be
installed.
- •
- The module "Carp" is used for error handling.
- •
- The module "IO::Handle" is used to handle output pipes. Your
operating system must support pipes, of course.
INCOMPATIBILITIES¶
There are no known incompatibilities.
BUGS AND LIMITATIONS¶
$plot1->gnuplot_cmd("pause -1"); # send the gnuplot pause command
does not work. Use
$plot1->gnuplot_pause( );
There are no known bugs in this module. Please report problems to author.
Patches are welcome.
AUTHOR¶
Dr.-Ing. Fritz Mehner (mehner@fh-swf.de)
CREDITS¶
Stephen Marshall (smarshall at wsi dot com) contributed
"gnuplot_set_plot_titles".
Georg Bauhaus (bauhaus at futureapps dot de) contributed
"gnuplot_plot_xy_style".
Bruce Ravel (bravel at bnl dot gov) contributed "gnuplot_plot_many"
and "gnuplot_plot_many_style" and made method calls chainable.
LICENSE AND COPYRIGHT¶
Copyright (C) 2005-2008 by Fritz Mehner
This module is free software; you can redistribute it and/or modify it under the
same terms as Perl itself. See perldoc perlartistic. This program is
distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
SEE ALSO¶
gnuplot(1).