NAME

       Lire::ChartType - Base interface for all ChartType.

SYNOPSIS

         use base qw/ Lire::ChartType /;

DESCRIPTION

       This package defines the interface which is implemented by all the different charts that Lire is able to
       produce using the ploticus pl(1) command.

       A chart type will generate a chart using data from a subreport.

META INFORMATION METHODS

       The Lire::ChartType interface extends the Lire::Plugin interface, so they must implement all standard
       meta-information methods (name(), title(), description()).

GENERATING A CHART

   write_chart( $chart_config, $subreport, [ %params ] )
       This will write a chart from the data contained in the Lire::Report::Subreport $subreport using the
       configuration $chart_config. Additional parameters are passed in 'key' => $value form. The $chart_config
       parameters should be a Lire::Config::Dictionary object instantiated from a Lire::Config::ChartSpec.

       outputdir
           Directory where the file will be created. Use the working directory by default.

       format
           One of eps, png, jpeg or gif. Default to the configuration variable lr_image_format.

       The  function  returns  the  path  to  the  created  file.  The  filename is generated base on the 'name'
       configuration value or the subreport's id if the other isn't defined. The extension is added based on the
       output format.

       It returns the file where the chart was written.

   prefab()
       This method must be implemented by the subclass  and  should  return  a  string  representing  the  first
       parameters to pass to ploticus (that is either -prefab name or the path to a script file).

   write_parameters( $chart_config, $fh )
       This  method  is used to write parameters to the ploticus file handle.  This is the place to use the #set
       command to set all of the prefabs parameters. Subclass must chain to this implementation for the standard
       chart parameters. It  also  write  '#set  name'  directives  for  each  numerical  variables  defined  by
       get_vars().

   write_data( $chart_config, $subreport, $fh )
       This  method  is  used by the write_chart() implementation to write the chart data from $subreport to the
       Ploticus commond opened on $fh. It uses the get_vars() method to  obtain  the  numerical  variables  that
       should  be  written  to  the stream and the encode_value() method to marshall values before writing them.
       Before any data is written to $fh the maximum value on the Y axis is determined and output as a  ploticus
       setting. (ploticus fails if this is not set, a single bar is drawn and the value is greater than 1.1e9.)

   get_vars( $chart_config )
       This   method   should   be  overriden  by  subclasses  to  return  an  array  reference  containing  the
       Lire::Report::ColumnInfo specifying the numerical column's of  data  that  should  be  written.  This  is
       usually specified using a ReferenceSpec with the 'numerical_variables' index.

       These variables will start at the ploticus index 2 (@2).

   encode_value( $value )
       By  default,  this  method just returns the 'content' component of the item when the $value is a name and
       the 'value' component otherwise. It can used for data type that needs special encoding (like datetime).

SEE ALSO

        Lire::PluginManager(3pm) Lire::Config::ChartSpec(3pm)

AUTHOR

       Francis J. Lacoste <flacoste@logreport.org>

VERSION

       $Id: ChartType.pm,v 1.17 2006/07/29 18:01:14 vanbaal Exp $

COPYRIGHT

       Copyright (C) 2004 Stichting LogReport Foundation LogReport@LogReport.org

       This file is part of Lire.

       Lire is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
       License as published by the Free Software Foundation; either version  2  of  the  License,  or  (at  your
       option) any later version.

       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 the GNU General  Public
       License for more details.

       You  should have received a copy of the GNU General Public License along with this program (see COPYING);
       if not, check with http://www.gnu.org/copyleft/gpl.html.

Lire 2.1.1                                         2006-07-29                                     ChartType(3pm)