NAME

Chart::Gnuplot - Plot graph using Gnuplot on the fly

SYNOPSIS

use Chart::Gnuplot;

# Data
my @x = (-10 .. 10);
my @y = (0 .. 20);

# Create chart object and specify the properties of the chart
my $chart = Chart::Gnuplot->new(
    output => "fig/simple.png",
    title  => "Simple testing",
    xlabel => "My x-axis label",
    ylabel => "My y-axis label",
    ....
);

# Create dataset object and specify the properties of the dataset
my $dataSet = Chart::Gnuplot::DataSet->new(
    xdata => \@x,
    ydata => \@y,
    title => "Plotting a line from Perl arrays",
    style => "linespoints",
    ....
);

# Plot the data set on the chart
$chart->plot2d($dataSet);

##################################################

# Plot many data sets on a single chart
$chart->plot2d($dataSet1, $dataSet2, ...);

DESCRIPTION

This module is to plot graphs uning GNUPLOT on the fly. In order to use this module, gnuplot need to be installed. If image format other than PS, PDF and EPS is required to generate, the convert program of ImageMagick is also needed.

To plot chart using Chart::Gnuplot, a chart object and at least one dataset object are needed to be created. Information about the chart such as output file, chart title, axes labels and so on is specified in the chart object. Dataset object contains information about the dataset to be plotted, including source of the data points, dataset label, color used to plot and more.

After chart object and dataset object(s) are created, the chart can be plotted using the plot2d, plot3d or multiplot method of the chart object, e.g.

# $chart is the chart object
$chart->plot2d($dataSet1, $dataSet2, ...);

To illustate the feature of Chart::Gnuplot, the best way is to show by examples.

CHART OBJECT

The chart object can be initiated by the c<new> method. Properties of the chart may be specified optionally when the object is initiated:

my $chart = Chart::Gnuplot->new(%options);

Chart Options

output

Output file of the graph. By default, the image format is detected automatically by the extension of the filename. However, it can also be changed manually by using the format conversion methods such as convert and png (see sessions below).

The supported image formats are:

bmp  : Microsoft Windows bitmap
epdf : Encapsulated Portable Document Format
epi  : Encapsulated PostScript Interchange format
eps  : Encapsulated PostScript
gif  : Graphics Interchange Format
jpg  : Joint Photographic Experts Group JFIF format
pdf  : Portable Document Format
png  : Portable Network Graphics
ppm  : Portable Pixmap Format
ps   : PostScript file
psd  : Adobe Photoshop bitmap file
xpm  : X Windows system pixmap

If the filename has no extension, postscipt will be used.

title

Title of the chart. E.g.,

title => "Chart title"

Properties of the chart title can be specified in hash. E.g.,

title => {
    text => "Chart title",
    font => "arial, 20",
    .....
}

Supported properties are:

text     : title in plain text
font     : font face (and optionally font size)
color    : font color
offset   : offset relative to the default position
enhanced : title contains subscript/superscipt/greek? (on/off)

Default values would be used for properties not specified. These properties has no effect on the main title of the multi-chart (see multiplot).

xlabel

Label of the x-axis. E.g.

xlabel => "Bottom axis label"

Properties of the chart title can be specified in hash, similar to the chart title. Supported properties are:

text     : title in plain text
font     : font face (and optionally font size)
color    : font color
offset   : offset relative to the default position
rotate   : rotation by degrees
enhanced : title contains subscript/superscipt/greek? (on/off)

ylabel

Label of the y-axis. See xlabel.

x2label

Label of the secondary x-axis (displayed on the top of the graph). See xlabel.

y2label

Label of the secondary y-axis (displayed on the right of the graph). See xlabel.

zlabel

Label of the z-axis in 3D plots. See xlabel.

xrange

Range of the x-axis in the plot, e.g.

xrange => [0, "pi"];

yrange

Range of the y-axis in the plot.

x2range

Range of the secondary x-axis in the plot.

y2range

Range of the secondary y-axis in the plot.

zrange

Range of the z-axis in the 3D plot.

xtics

The tics and tic label of the x-axis.

ytics

The tics and tic label of the y-axis.

x2tics

The tics and tic label of the x2-axis.

y2tics

The tics and tic label of the y2-axis.

legend

Legend describing the plots. Supported properties are:

position : position of the legend
width    : number of character widths to be added or subtracted to the
         : region of the legend
height   : number of character heights to be added or subtracted to the
         : region of the legend
align    : alignment of the text label. Left or right (default)
order    : order of the keys
title    : title of the legend
sample   : format of the sample lines
border   : border of the legend. See L<border> for available options

E.g.

legend => {
   position => "outside bottom",
   width    => 3,
   height   => 4,
   align    => "right",
   order    => "horizontal reverse",
   title    => "Title of the legend",
   sample   => {
       length   => 3,
       position => "left",
       spacing  => 2,
   },
   border   => {
       linetype => 2,
       width    => 1,
       color    => "blue",
   },
}

timeaxis

Specify the axes of which the tic labels are date/time string. Possible values are combinations of "x", "y", "x2", and "y2" joined by ",". E.g.

timeaxis => "x, y2"

means that the x-axis and y2-axis are data/time axes.

border

Border of the graph. Properties supported are "linetype", "width", and "color". E.g.

border => {
    linetype => 3,
    width    => 2,
    color    => '#ff00ff',
}

grid

Grid lines.

bmargin

Bottom margin (in character height). This option has no effect in 3D plots.

lmargin

Left margin (in character width)

rmargin

Right margin (in character width). This option has no effect in 3D plots.

tmargin

Top margin (in character height). This option has no effect in 3D plots.

orient

Orientation of the image. Possible values are "lanscape" and "portrait".

imagesize

Size (length and height) of the image relative to the default.

size

Size of the chart relative to the chart size. This is useful in some multi-plot such as inset chart.

origin

Origin of the chart. This is useful in some multi-plot such as inset chart.

timestamp

Time stamp of the plot. To place the time stamp with default setting,

timestamp => 'on'

To set the format of the time stamp as well, e.g.,

timestamp => {
   fmt    => '%d/%m/%y %H:%M',
   offset => "10,-3",
   font   => "Helvetica",
}

bg (experimental)

Background color of the chart. This option is experimental.

plotbg (experimental)

Background color of the plot area. This option has no effect in 3D plots and is experimental.

gnuplot

The path of Gnuplot installed. This option is useful if you have multiple versions of Gnuplot installed.

terminal

The terminal that Gnuplot use. The default terminal is "postscript". This attribute is not recommended to be changed unless you are familiar with the Gnuplot syntax. Please test carefully before using this in production code.

Terminal is not necessarily related to the output image format. You may convert the image format by the convert() method.

Chart Methods

new

my $chart = Chart::Gnuplot->new(%options);

Constructor of the chart object. If no option is specified, default values would be used. See "Chart Options" for available options.

set

General set methods for arbitrary number of options.

$chart->set(%options);

plot2d

$chart->plot2d(@dataSets);

Plot the data sets in a 2D chart. Each dataset is represented by a dataset object.

plot3d

$chert->plot3d(@dataSets);

Plot the data sets in a 3D chart. Each dataset is represented by a dataset object. It is not yet completed. Only basic features are supported.

multiplot

$chert->multiplot(@charts);

Plot multiple charts in the same image.

add2d

Add a 2D dataset to a chart without plotting it out immediately. Used with multiplot.

add3d

Add a 3D dataset to a chart without plotting it out immediately. Used with multiplot.

label

Add an arbitrary text label. e.g.,

$chart->label(
    text       => "This is a label",
    position   => "0.2, 3 left",
    offset     => "2,2",
    rotate     => 45,
    font       => "arial, 15",
    fontcolor  => "dark-blue",
    pointtype  => 3,
    pointsize  => 5,
    pointcolor => "blue",
);

convert

$chart->convert($imageFmt);

Convert the image format to $imageFmt. See "Chart Options" for supported image formats.

png

$chart->png;

Change the image format to PNG.

gif

$chart->gif;

Change the image format to GIF.

jpg

$chart->jpg;

Change the image format to JPEG.

ps

$chart->ps;

Change the image format to postscript.

pdf

$chart->pdf

Change the image format to PDF.

command

$chart->command($gnuplotCommand);

Add a gnuplot command. This method is useful for the Gnuplot features that have not yet implemented.

DATASET OBJECT

The dataset object can be initiated by the new method. Properties of the dataset may be specified optionally when the object is initiated:

my $dataset = Chart::Gnuplot::DataSet->new(%options);

The data source of the dataset can be specified by either one of the following ways:

1. Arrays of x values, y values and z values (in 3D plots) of the data points.
2. Array of data points. Each point is specified as an array of x, y, z coordinates
3. Data file.
4. Mathematical expression (for a function).

Dataset Options

xdata

The x values of the data points.

xdata => \@x

If xdata is omitted but ydata is defined, the integer index starting from 0 would be used for xdata.

ydata

The y values of the data points. See xdata.

zdata

The z values of the data points. See xdata

points

Data point matrix of the format [[x1,y1], [x2,y2], [x3,y3], ...]

points => \@points

datafile

Input data file

datafile => $file

The data files are assumed to be space-separated, with each row corresponding to one data point. Lines beginning with "#" are considered as comments and would be ignored. Other formats are not supported at this moment.

func

Mathematical function to be plotted. E.g.

func => "sin(x)*x**3"

Supported functions:

abs(x)       : absolute value
acos(x)      : inverse cosine
acosh(x)     : inverse hyperbolic cosine
arg(x)       : complex argument
asin(x)      : inverse sine
asinh(x)     : inverse hyperbolic sine
atan(x)      : inverse tangent
atanh(x)     : inverse hyperbolic tangent
besj0(x)     : zeroth order Bessel function of the first kind
besj1(x)     : first order Bessel function of the first kind
besy0(x)     : zeroth order Bessel function of the second kind
besy1(x)     : first order Bessel function of the second kind
ceil(x)      : ceiling function
cos(x)       : cosine
cosh(x)      : hyperbolic cosine
erf(x)       : error function
erfc(x)      : complementary error function
exp(x)       : expontial function
floor(x)     : floor function
gamma(x)     : gamma function
ibeta(a,b,x) : incomplete beta function
inverf(x)    : inverse error function
igamma(a,x)  : incomplete gamma function
imag(x)      : imaginary part
invnorm(x)   : inverse normal distribution function
int(x)       : integer part
lambertw(x)  : Lambert W function
lgamma(x)    : log gamma function
log(x)       : natural logarithm
log10(x)     : common logarithm
norm(x)      : normal distribution function
rand(x)      : pseudo random number
real(x)      : real part
sgn(x)       : sign function
sin(x)       : sine
sinh(x)      : hyperbolic sine
sqrt(x)      : square root
tan(x)       : tangent
tanh(x)      : hyperbolic tangent

Please see the Gnuplot manual for updated information.

Supported mathematical constants:

pi : the circular constant 3.14159...

Supported arithmetic operators:

addition           : +
division           : /
exponentiation     : **
factorial          : !
modulo             : %
multiplication     : *
subtraction        : -, e.g., 1-2
unary minus        : -, e.g., -1

Supported logical operations:

and                      : &&
complement               : ~
equality                 : ==
greater than             : >
greater than or equal to : >=
inequality               : !=
less than                : <
less than or equal to    : <= 
negation                 : !
or                       : ||
if ... than else ...     : ?:, e.g., a ? b : c

title

Title of the dataset (shown in the legend).

style

The plotting style for the dataset, including

lines          : join adjacent points by straight lines
points         : mark each points by a symbol
linespoints    : both "lines" and "points"
dots           : dot each points. Useful for large datasets
impluses       : draw a vertical line from the x-axis to each point
steps          : join adjacent points by steps
boxes          : draw a centered box from the x-axis to each point
xerrorbars     : "dots" with horizontal error bars
yerrorbars     : "dots" with vertical error bars
xyerrorbars    : both "xerrorbars" and "yerrorbars"
xerrorlines    : "linespoints" with horizontal error bars
yerrorlines    : "linespoints" with vertical error bars
xyerrorlines   : both "xerrorlines" and "yerrorlines"
boxerrorbars   : "boxes" with "yerrorbars"
boxxyerrorbars : use rectangles to represent the data with errors
financebars    : finance bars for open, high, low and close price
candlesticks   : candle sticks for open, high, low and close price

color

Color of the dataset in the plot. Can be a named color ot RBG (#RRGGBB) value. The supported color names can be found in the file doc/colors.txt in the distribution. E.g.

color => "#99ccff"
# or
color => "dark-red"

width

Line width used in the plot.

linetype

Line type.

pointtype

Point type.

pointsize

Point size of the plot.

fill

Filling string. Has effect only on plotting styles "boxes", "boxxyerrorbars" and "financebars".

axes

Axes used in the plot. Possible values are "x1y1", "x1y2", "x2y1" and "x2y2".

timefmt

Time format of the input data. The valid format are:

%d : day of the month, 1-31
%m : month of the year, 1-12
%y : year, 2-digit, 0-99
%Y : year, 4-digit
%j : day of the year, 1-365
%H : hour, 0-24
%M : minute, 0-60
%s : seconds since the Unix epoch (1970-01-01 00:00 UTC)
%S : second, 0-60
%b : name of the month, 3-character abbreviation
%B : name of the month

smooth

The smooth method used in plotting data points. Supported methods include cubic splines (csplines), Bezier curve (bezier) and other. Please see Gnuplot manual for details.

Dataset Methods

new

my $dataset = Chart::Gnuplot::DataSet->new(%options);

Constructor of the dataset object. If no option is specified, default values would be used. See "Dataset Options" for available options.

EXAMPLES

Some simple examples are shown below. Many more come with the distribution.

1. Plot a mathematical expression

my $chart = Chart::Gnuplot->new(
    output => "expression.png"
);

my $dataSet = Chart::Gnuplot::DataSet->new(
    func => "sin(x)"
);

$chart->plot2d($dataSet);

2. Plot from two Perl arrays, one for the x-axis data and the other the y-axis.

my $chart = Chart::Gnuplot->new(
    output => "arrays.png"
);

my $dataSet = Chart::Gnuplot::DataSet->new(
    xdata => \@x,
    ydata => \@y,
);

$chart->plot2d($dataSet);

3. Plot x-y pairs

# Data
my @xy = (
    [1.1, -3],
    [1.2, -2],
    [3.5,  0],
    ...
);

my $chart = Chart::Gnuplot->new(
    output => "points.png"
);

my $dataSet = Chart::Gnuplot::DataSet->new(
    points => \@xy
);

$chart->plot2d($dataSet);

4. Plot data from a data file

my $chart = Chart::Gnuplot->new(
    output => "file.png"
);

my $dataSet = Chart::Gnuplot::DataSet->new(
    file => "in.dat"
);

$chart->plot2d($dataSet);

5. Chart title, axis label and legend

# Chart object
my $chart = Chart::Gnuplot->new(
    output => "trigonometric.gif",
    title  => "Three basic trigonometric functions",
    xlabel => "angle in radian",
    ylabel => "function value"
);

# Data set objects
my $sine = Chart::Gnuplot::DataSet->new(
    func  => "sin(x)",
    title => "sine function"
);
my $cosine = Chart::Gnuplot::DataSet->new(
    func  => "cos(x)",
    title => "cosine function"
);
my $tangent = Chart::Gnuplot::DataSet->new(
    func  => "tan(x)",
    title => "tangent function"
);

$chart->plot2d($sine, $cosine, $tangent);

6. Plot a financial time series

my $chart = Chart::Gnuplot->new(
    output   => "dj.ps",
    title    => "Dow-Jones Index time series",
    timeaxis => 'x',
    xtics    => {
        labelfmt => '%b%y',
    },
);

my $dow = Chart::Gnuplot::DataSet->new(
    file    => "dj.dat",
    timefmt => '%Y-%m-%d',      # time format of the input data
    style   => "candlesticks",
    grid    => 'on',
);

$chart->plot2d($dow);

7. Plot several graphs on the same image

my $chart = Chart::Gnuplot->new(
    output => "multiplot.gif",
);

my $left = Chart::Gnuplot->new();
my $sine = Chart::Gnuplot::DataSet->new(
    func  => "sin(x)",
);
$left->add2d($sine);

my $center = Chart::Gnuplot->new();
my $cosine = Chart::Gnuplot::DataSet->new(
    func  => "cos(x)",
);
$center->add2d($cosine);

my $right = Chart::Gnuplot->new();
my $tangent = Chart::Gnuplot::DataSet->new(
    func  => "tan(x)",
);
$right->add2d($tangent);

# Place the Chart::Gnuplot objects in matrix to indicate their locations
$chart->multiplot([
    [$left, $center, $right]
]);

FUTURE PLAN

1. Improve the manual.
2. Add more control to the 3D plots.
3. Add curve fitting method.
4. Add method to copy Chart and DataSet objects.
5. Improve the testsuite.
6. Reduce number of temporary files generated.

REQUIREMENTS

File::Copy, File::Temp

Gnuplot http://www.gnuplot.info

ImageMagick http://www.imagemagick.org (for full feature)

TEST ENVIRONMENT

This version is tested against Gnuplot 4.2 patchlevel 0 and patchlevel 2 in Linux.

AUTHOR

Ka-Wai Mak <kwmak@cpan.org>

COPYRIGHT

LICENSE

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

To install Chart::Gnuplot, copy and paste the appropriate command in to your terminal.

cpanm

cpanm Chart::Gnuplot

CPAN shell

perl -MCPAN -e shell
install Chart::Gnuplot

For more information on module installation, please visit the detailed CPAN module installation guide.

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NAME

SYNOPSIS

DESCRIPTION

CHART OBJECT

Chart Options

output

title

xlabel

ylabel

x2label

y2label

zlabel

xrange

yrange

x2range

y2range

zrange

xtics

ytics

x2tics

y2tics

legend

timeaxis

border

grid

bmargin

lmargin

rmargin

tmargin

orient

imagesize

size

origin

timestamp

bg (experimental)

plotbg (experimental)

gnuplot

terminal

Chart Methods

new

set

plot2d

plot3d

multiplot

add2d

add3d

label

convert

png

gif

jpg

ps

pdf

command

DATASET OBJECT

Dataset Options

xdata

ydata

zdata

points

datafile

func

title

style

color

width

linetype

pointtype

pointsize

fill

axes

timefmt

smooth

Dataset Methods

new

EXAMPLES

FUTURE PLAN

REQUIREMENTS

TEST ENVIRONMENT

SEE ALSO