PNGgraph - Graph Plotting Module for Perl 5
use PNGgraph::moduleName;
PNGgraph is a perl5 module to create and display PNG output for a graph. The following classes for graphs with axes are defined:
PNGgraph::lines
Create a line chart.
PNGgraph::bars
Create a bar chart.
PNGgraph::points
Create an chart, displaying the data as points.
PNGgraph::linespoints
Combination of lines and points.
PNGgraph::area
Create a graph, representing the data as areas under a line.
PNGgraph::mixed
Create a mixed type graph, any combination of the above. At the moment this is fairly limited. Some of the options that can be used with some of the individual graph types won't work very well. Multiple bar graphs in a mixed graph won't display very nicely.
Additional types:
PNGgraph::pie
Create a pie chart.
See the samples directory in the distribution.
Fill an array of arrays with the x values and the values of the data sets. Make sure that every array is the same size, otherwise PNGgraph will complain and refuse to compile the graph.
@data = ( ["1st","2nd","3rd","4th","5th","6th","7th", "8th", "9th"], [ 1, 2, 5, 6, 3, 1.5, 1, 3, 4] [ sort { $a <=> $b } (1, 2, 5, 6, 3, 1.5, 1, 3, 4) ] );
If you don't have a value for a point in a certain dataset, you can use undef, and PNGgraph will skip that point.
Create a new PNGgraph object by calling the new operator on the graph type you want to create (chart is bars, lines, points, linespoints or pie).
$my_graph = new PNGgraph::chart( );
Set the graph options.
$my_graph->set( x_label => 'X Label', y_label => 'Y label', title => 'Some simple graph', y_max_value => 8, y_tick_number => 8, y_label_skip => 2 );
Output the graph
$my_graph->plot_to_png( "sample01.png", \@data );
Create a new object $graph with optional width and heigth. Default width = 400, default height = 300. chart is either bars, lines, points, linespoints, area or pie.
Set the colour of the text. This will set the colour of the titles, labels, and axis labels to colour name. Also see the options textclr, labelclr and axislabelclr.
Set the font that will be used for the title of the chart. Possible choices are defined in GD. NB. If you want to use this function, you'll need to use GD. At some point I'll rewrite this, so you can give this a number from 1 to 4, or a string like 'large' or 'small'. On the other hand, I might not, if Thomas Boutell decides to support more fonts.
Plot the chart, and return the PNG data.
Plot the chart, and write the PNG data to filename.
Set chart options. See OPTIONS section.
Set the font that will be used for the label of the pie or the values on the pie. Possible choices are defined in GD. See also set_title_font.
Set the font for the x and y axis label, and for the x and y axis value labels. See also set_title_font.
The width and height of the png file in pixels Default: 400 x 300. NB At the moment, these are read-only options. If you want to set the size of a graph, you will have to do that with the new method.
Top, bottom, left and right margin of the PNG. These margins will be left blank. Default: 0 for all.
Name of a logo file. This should be a PNG file. Default: no logo.
Factor to resize the logo by, and the position on the canvas of the logo. Possible values for logo_position are 'LL', 'LR', 'UL', and 'UR'. (lower and upper left and right). Default: 'LR'.
If set to a true value, the produced PNG will have the background colour marked as transparent (see also option bgclr). Default: 1.
If set to a true value, the produced PNG will be interlaced. Default: 1.
Background, foreground, text, label, axis label and accent colours.
This controls the colours for the bars, lines, markers, or pie slices. This should be a reference to an array of colour names as defined in PNGgraph::colour (perldoc PNGgraph::colour for the names available).
perldoc PNGgraph::colour
$graph->set( dclrs => [ qw(green pink blue cyan) ] );
The first (fifth, ninth) data set will be green, the next pink, etc. Default: [ qw(lred lgreen lblue lyellow lpurple cyan lorange) ]
options for bars, lines, points, linespoints and area charts.
If long_ticks is a true value, ticks will be drawn the same length as the axes. Otherwise ticks will be drawn with length tick_length. if tick_length is negative, the ticks will be drawn outside the axes. Default: long_ticks = 0, tick_length = 4.
If x_ticks is a true value, ticks will be drawm for the x axis. These ticks are subject to the values of long_ticks and tick_length. Default: 1.
Number of ticks to print for the Y axis. Use this, together with y_label_skip to control the look of ticks on the y axis. Default: 5.
This can be either a string, or a reference to a subroutine. If it is a string, it will be taken to be the first argument to an sprintf, with the value as the second argument:
$label = sprintf( $s->{y_number_format, $value );
If it is a code reference, it will be executed with the value as the argument:
$label = &{$s->{y_number_format}}($value);
This can be useful, for example, if you want to reformat your values in currency, with the - sign in the right spot. Something like:
sub y_format { my $value = shift; my $ret; if ($value >= 0) { $ret = sprintf("\$%d", $value * $refit); } else { $ret = sprintf("-\$%d", abs($value) * $refit); } return $ret; } $my_graph->set( 'y_number_format' => \&y_format );
(Yes, I know this can be much shorter and more concise)
Default: undef.
Print every x_label_skipth number under the tick on the x axis, and every y_label_skipth number next to the tick on the y axis. Default: 1 for both.
Force a print of all the x ticks, even if x_label_skip is set to a value Default: 0.
Controls the position of the X axis label (title). The value for this should be between 0 and 1, where 0 means aligned to the left, 1 means aligned to the right, and 1/2 means centered. Default: 3/4
Controls the position of both Y axis labels (titles). The value for this should be between 0 and 1, where 0 means aligned to the bottom, 1 means aligned to the top, and 1/2 means centered. Default: 1/2
If set to a true value, the X axis labels will be printed vertically. This can be handy in case these labels get very long. Default: 0.
If set to a true value, the values of the ticks on the x or y axes will be plotted next to the tick. Also see x_label_skip, y_label_skip. Default: 1 for both.
Draw the axes as a box, if true. Default: 1.
Use two separate axes for the first and second data set. The first data set will be set against the left axis, the second against the right axis. If this is set to a true value, trying to use anything else than 2 datasets will generate an error. Default: 0.
If set to a true value, the axis for y values of 0 will always be drawn. This might be useful in case your graph contains negative values, but you want it to be clear where the zero value is. (see also zero_axis_only and box_axes). Default: 0.
If set to a true value, the zero axis will be drawn (see zero_axis), and no axis at the bottom of the graph will be drawn. The labels for X values will be placed on the zero exis. Default: 0.
Maximum and minimum value displayed on the y axis. If two_axes is a true value, then y1_min_value, y1_max_value (for the left axis), and y2_min_value, y2_max_value (for the right axis) take precedence over these.
The range (y_min_value..y_max_value) has to include all the values of the data points, or PNGgraph will die with a message.
For bar and area graphs, the range (y_min_value..y_max_value) has to include 0. If it doesn't, the values will be adapted before attempting to draw the graph.
Default: Computed from data sets.
This space will be left blank between the axes and the text. Default: 4.
If set to 0, bars of different data sets will be drawn next to each other. If set to 1, they will be drawn in front of each other. If set to 2 they will be drawn on top of each other. Default: 0.
If you have negative values in your data sets, setting overwrite to 2 might produce odd results. Of course, the graph itself would be quite meaningless, because overwrite = 2 is meant to show some cumulative effect.
First of all: PNGgraph does not support numerical x axis the way it should. Data for X axes should be equally spaced. That understood: There is some support to make the printing of graphs with numerical X axis values a bit better, thanks to Scott Prahl. If the option x_tick_number is set to a defined value, PNGgraph will attempt to treat the X data as numerical.
x_tick_number
Extra options are:
If set to 'auto', PNGgraph will attempt to format the X axis in a nice way, based on the actual X values. If set to a number, that's the number of ticks you will get. If set to undef, PNGgraph will treat X data as labels. Default: undef.
The minimum and maximum value to use for the X axis. Default: computed.
See y_number_format
See y_label_skip
Number of pixels to leave open between bars. This works well in most cases, but on some platforms, a value of 1 will be rounded off to 0. Default: 0
Which line types to use for lines and linespoints graphs. This should be a reference to an array of numbers:
$graph->set( line_types => [3, 2, 4] );
Available line types are 1: solid, 2: dashed, 3: dotted, 4: dot-dashed.
Default: [1] (always use solid)
Controls the length of the dashes in the line types. default: 6.
The width of the line used in lines and linespoints graphs, in pixels. Default: 1.
This controls the order of markers in points and linespoints graphs. This should be a reference to an array of numbers:
$graph->set( markers => [3, 5, 6] );
Available markers are: 1: filled square, 2: open square, 3: horizontal cross, 4: diagonal cross, 5: filled diamond, 6: open diamond, 7: filled circle, 8: open circle.
Default: [1,2,3,4,5,6,7,8]
The size of the markers used in points and linespoints graphs, in pixels. Default: 4.
A reference to an array with graph types, in the same order as the data sets. Possible values are:
$graph->set( types => [qw(lines bars points area linespoints)] ); $graph->set( types => ['lines', undef, undef, 'bars'] );
values that are undefined or unknown will be set to default_type.
default_type
Default: all set to default_type
The type of graph to draw for data sets that either have no type set, or that have an unknown type set.
Default: lines
At the moment legend support is minimal.
Methods
Sets the keys for the legend. The elements of @legend_keys correspond to the data sets as provided to plot() or plot_to_png().
If a key is undef or an empty string, the legend entry will be skipped.
Sets the font for the legend text (see also set_title_font). Default: GD::gdTinyFont.
Options
Where to put the legend. This should be a two letter key of the form: 'B[LCR]|R[TCB]'. The first letter sipngies the placement (Bottom or Right), and the second letter signifies the alignment (Left, Right, Center, Top, or Bottom). Default: 'BC'
If the legend is placed at the bottom, some calculations will be made to ensure that there is some 'intelligent' wrapping going on. if the legend is placed at the right, all entries will be placed below each other.
The number of pixels to place around a legend item, and between a legend 'marker' and the text. Default: 4
The width and height of a legend 'marker' in pixels. Defaults: 12, 8
If you, for some reason, need to force the legend at the bottom to have a specific number of columns, you can use this. Default: computed
If set to a true value, the pie chart will be drawn with a 3d look. Default: 1.
The thickness of the pie when 3d is true. Default: 0.1 x PNG y size.
The angle at which the first data slice will be displayed, with 0 degrees being "6 o'clock". Default: 0.
All references to colours in the options for this module have been shortened to clr. The main reason for this was that I didn't want to support two spellings for the same word ('colour' and 'color')
Wherever a colour is required, a colour name should be used from the package PNGgraph::colour. perldoc PNGgraph::colour should give you the documentation for that module, containing all valid colour names. I will probably change this to read the systems rgb.txt file if it is available.
Wherever a font name is required, a font from GD should be used.
Martien Verbruggen ported to GD 1.20+ (PNG) by Steve Bonds
for PNGgraph questions: email: sbonds@agora.rdrop.com
for GIFgraph questions: email: mgjv@comdyn.com.au
Copyright (C) 1995-1998 Martien Verbruggen. Copyright (C) 1999 Steve Bonds. All rights reserved. This package is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
To install PNGgraph, copy and paste the appropriate command in to your terminal.
cpanm
cpanm PNGgraph
CPAN shell
perl -MCPAN -e shell install PNGgraph
For more information on module installation, please visit the detailed CPAN module installation guide.