Chart::Manual::Methods - user API
This are all methods for the chart user.
Loads all data of a chart (one or more data sets) from a file. (Works only if no
data yet added.) You have to either provide a filename or filehandle
(OLD_SCHOOL or $scalar).
$graph->add_dataset( 'file.tsv' );
$graph->add_dataset( $file_handle );
$graph->add_dataset( FILE_HANDLE );
An optional second argument, which defaults to 'set' can change the file format
if set to 'pt'. In 'set' mode every row of the file content is fed to
"add_dataset", in 'pt' every row get loaded like via
"add_pt". In other words: 'pt' transposes the data table.
$graph->add_dataset( 'file.tsv', 'pt' );
The arbitrary named text files have to contain one or several rows of numbers.
The numbers need to be separated by spaces or tabs (\t) (mixing allowed). Perl
style comments or empty lines will be ignored, but rows containing different
amount of numbers will cause problems.
Adding a list of values as one data set. That is one row in the overall data
table. The first data set are usually x-axis labels (domain set). Make sure
all sets have the same length.
$graph->add_dataset( 1, 2, 3, ... );
$graph->add_dataset( [1, 2, 3, ...] );
For instances with Points, Lines or Bars one data set is represented by a set of
graphic items (points, bars or line) of one color.
Adds (appends) to each already existing data set one value. That is a column in
the overall data table. In this example it adds to set 0 the value 3, to set 1
the 6 and so forth. Make sure that the list lengths matches the number of
already existing data sets.
$graph->add_pt( 3, 6, 9, ... );
$graph->add_pt( [3, 6, 9, ...] );
Creates same JPEG image as "jpeg", but outputs to STDOUT. Since no
file name or handle needed, only the optional data argument is acceptable.
$graph->cgi_jpeg( );
my @data = ([1, 2, 3], # data set 0
[3, 4, 5]); # data set 1
$graph->cgi_jpeg( \@data );
Creates same PNG image as "png", but outputs to STDOUT. Since no file
name or handle needed, only the optional data argument is acceptable.
$graph->cgi_png( );
my $data = [[1, 2, 3], # data set 0
[3, 4, 5] ]; # data set 1
$graph->cgi_png( $data );
Needs no arguments and deletes all so far added data.
Return all data (array of arrays) given to a graph.
When creating a chart for web purposes by "cgi_jpeg" or
"cgi_png", you maybe want the information, where the areas of
interests in the image are located, that should react to a users click. (HTML
tag map). These areas are bounding boxes around the drawn bars or points. You
will get per box the values: x1, y1, x2, y2 in one array. These arrays are
again in an Array holding, all boxes from one data set. The highest level
array again holds all arrays of all data sets, beginning with index 1.
This method can only be called, if the functionality is activated by setting the
property: imagemap to 'true'.
$graph->set( imagemap => 'true');
my $image_map = $graph->imagemap_dump();
say "coordinates of first bar, first data set:";
say for @{$image_map->[1][0]};
Creates an JPEG image from given data and properties. Accepts a file name or a
file handle (raw or in a SCALAR). The method closes the file handle.
$graph->jpeg( 'image.jpg' );
$graph->jpeg( $file_handle );
$graph->jpeg( FILE_HANDLE );
$graph->jpeg( 'image.jpg', $data );
$graph->jpeg( 'image.jpg', 'data_file.tsv' );
$graph->jpeg( 'image.jpg', $file_handle );
$graph->jpeg( 'image.jpg', FILE_HANDLE );
The second, optional argument is the data in form of an array of arrays
reference. This only works, if there is no data already given to the object.
Alternatively the data can also be loaded from a file, just provide the
filename or filehandle (modern in SCALAR or old school). Read more about the
file format at "add_datafile" and note that this method has another
option for loading transposed data tables.
Creates a new chart object. Takes two optional arguments, which are the width
and height of the to be produced image in pixels. Defaults for that are 400 x
300.
my $graph = Chart::Bars->new ( );
my $graph = Chart::Bars->new (600, 700);
Instead of Bars, you can also use: Composite, Direction, ErrorBars,
HorizontalBars, Lines, LinesPoints, Mountain, Pareto, Pie, Points, Split and
StackedBars. To know more about them read Chart::Manual::Types.
Creates an PNG image from given data and properties. Accepts a file name or a
file handle (raw or in a SCALAR). The method closes the file handle.
$graph->png( 'image.png' );
$graph->png( $file_handle );
$graph->png( FILE_HANDLE );
$graph->png( 'image.png', $data );
$graph->png( 'image.png', 'data_file.tsv' );
$graph->png( 'image.png', $file_handle );
$graph->png( 'image.png', FILE_HANDLE );
The second, optional argument is the data in form of an array of arrays
reference. This only works, if there is no data already given to the object.
Alternatively the data can also be loaded from a file, just provide the
filename or filehandle (modern in SCALAR or old school). Read more about the
file format at "add_datafile" and note that this method has another
option for loading transposed data tables.
Creates same JPEG image as "jpeg" but returns the image binary into a
variable, not to STDOUT or a file.
my $image_binary = $graph->scalar_jpeg();
my $image_binary = $graph->scalar_jpeg( $data );
Creates same PNG image as "png" but returns the image binary into a
variable, not to STDOUT or a file.
my $image_binary = $graph->scalar_png();
my $image_binary = $graph->scalar_png( $data );
Method to change one or more chart properties in hash form.
$chart->set ( property_name => 'new value', ... );
$chart->set ( %properties );
Different chart types react to different properties, which are all listed and
explained under Chart::Manual::Properties.
Copyright 2022 Herbert Breunung.
This program is free software; you can redistribute it and/or modify it under
same terms as Perl itself.
Herbert Breunung, <
[email protected]>