NAME

HTML::BarGraph - generate multiset bar graphs using plain HTML

SYNOPSIS

use HTML::BarGraph;

 print graph( 
             direction           => 'h',        ###  or 'v' or '|' / '-'
             graphminsize        => 250,
             bartype             => 'pixel',    ###  or 'html'
             barlength           => 100,
             barwidth            => 10 ,
             baraspect           => .03,
             color               => 'blue',
             colors              => [ 'blue', 'red', 'lightblue' ],
             pixeldir            => '/images',
             pixelfmt            => 'PNG',
             data                => [ 
                                      [ val11, val12, ... ],
                                      [ val21, val22, ... ],
                                    ],
             tags                =>   [  one,  two, ...   ],
             setspacer           => 0,
             highlighttag        => [ tag1... ], ###  or tag1 (one value)
                # OR
             highlightpos        => [ 5, ...],   ###  or 5 (one value)
             highlightcolor      => 'red',
             addalt              => 1,
             showaxistags        => 1,
             showvalues          => 1,
             valuesuffix         => '%',
             valueprefix         => '=> ',
             bordertype          => 'flat',     ### or 'reised' 
             bordercolor         => '#333333',  ### or '#RRGGBB'
             borderwidth         => 1,
             bgcolor             => 'bisque',   ### or '#RRGGBB'
             textcolor           => 'black',    ### or '#RRGGBB'
             title               => 'title',
             titlecolor          => 'black',    ### or '#RRGGBB'
             titlealign          => 'center',   ### or 'left' or 'right'
             fontface            => 'sansserif',
             ylabel              => 'randoms',
             ylabelalign         => 'middle',   ### or 'top' or 'bottom'
             xlabel              => 'index',
             xlabelalign         => 'center',   ### or 'left' or 'right'
             labeltextcolor      => 'yellow',
             labelbgcolor        => 'black',
           );

DESCRIPTION

HTML::BarGraph is a module that creates graphics for one or more datasets, using plain HTML and, optionally, one-pixel images, which are stretched using the width and height attributes of the HTML img tag.

Multiple customization options are provided, such as the maximum bar length, bar colors etc.

The main subroutine, graph(), returns the HTML code for a graphic, and it accepts the following paramaters to define the graphic to be drawn:

direction: Default: h. This arg indicates the orientation of the graphic bars (horizontal, h or -, or vertical, v or |).
graphminsize: Optional arg to specify the minimum size of the graph in the direction of bar length; this can be used to get a consistent size when multiple graphics are displayed.
bartype: Default: html. This arg indicates whether the color bars should be build as HTML tables with a certain width, height and bgcolor, or out of a pixel image (value pixel) "stretched" with the width and hight attributes of img tag.
barlength: Default: 100. This arg indicates the length of the bar (in pixels) for the maximum value to be represented in the graphic.
barwidth: This arg indicates the width of a graphic's bar. If this arg is missing, it is calculated based on barlength and baraspect (using their default values if they are missing too).
baraspect: Default: 0.5. This arg indicates the aspect between the graphic bar's width and length. If both barwidth and baraspect are set, barwidth is used.
color: Default: blue. This arg indicates the default color to be used in drawing the graphic's bars for a single dataset representation (see also colors).
colors: Default: color. This arg should be an arrayref to a list of colors to be used in displaying the bars for multiple dataset graphs. If this arg is missing, the bars for all datasets will be displayed in color color. If the number of colors is smaller then the number of datasets to be represented, the values are "recycled". See also the Note for color argument.
pixeldir: Optional argument to indicate the directory where the color pixel files are located; for web scripts, this will have to be relative to the htdocs dir. This argument is ignored unless bartype is set to pixel.
pixelfmt: Default: PNG. Optional argument to indicate the graphic format of the color pixel files; the lc() of this argument's value is used as pixel file's extension (eg for PNG files, pixel files will be colorname.png. This argument is ignored unless bartype is set to pixel.
data: This is a required arg, and should contain the datasets to be represented in the graphic. It should be passed as arrayref of scalars (one set) or arrayrefs (multiple sets).
tags: If this arg is present, it should indicate the tags that should be used to identify the values in datasets. It should be an arrayref to a list of scalars, with at least that many elements as the number of elements in the largest dataset.
setspacer: Default: true. If true, this arg indicate that a space should be inserted to separate the consecutive representations of datasets, for a cleaner view. It is set to false on single set representations.
highlighttag: This arg has effect only for a single dataset representation, and only when tags is present as well (when dataset has no tags, see highlightpos). It can be an arrayref or scalar. If present, its values are compared with tags values, and in case it matches one exactly, the color of the correspondent bar will be set to highlightcolor , if specified (see below). If both highlighttag and highlightpos are specified, highlightpos is ignored.
highlightpos: This arg has effect only for a single dataset representation. It can be an arrayref or scalar. If present, the color of the correspondent 1-indexed position(s)in data will be set to highlightcolor, if specified (see below). If both highlighttag and highlightpos are specified, highlightpos is ignored.
highlightcolor: Default: red. This arg has effect only when highlighttag or highlightpos has effect (see above).
addalt: Default: true. If true, the addalt attribute is added to the HTML img tag, having as value the value that is represented on the bar.
showaxistags: Default: true. If true, tags are displayed along the base axis, if provided.
showvalues: Default: true. If true, the values are displayed at the end of each bar.
valuesuffix: If showvalues is true, any text string assigned to this argument will be displayed after the max value.
valueprefix: If showvalues is true, any text string assigned to this argument will be displayed before the max value.
bordertype: Default: undef. This arg sets the type of border the whole graph will be surrounded by. Valid values are flat (a frame of borderwidth width and bordercolor color will be drawn around the graphic, using <table> on <table> technique) or reised (the border attribute of the HTML table will be set to borderwidth value) (see below).
bordercolor: Default: black. This arg has effect only when bordertype is set to flat, and it indicates the color for the graph's frame). The value of this arg can be a "well-known" color name (ie white, black etc) or the RGB value, as specified in the HTML spec.
borderwidth: Default: 3 for bordertype set to flat, and 1 for reised. This arg has effect only when bordertype is set, and it indicates the width of the graph's border, in pixels.
bgcolor: Default: white. This arg indicates the background color of the graph area. See format of color args at bordercolor.
textcolor: Default: black. This arg indicates the font color of tags and values.
title: This arg indicates a string to be displayed as the title of the graph.
titlecolor: Default: textcolor. This arg only has effect when title is specified, and indicates the font color of title.
titlealign: Default: center. This arg only has effect when title is specified, and it indicates the justification of the title on the graph. Other valid values are left and right.
fontface: Default: TimesRoman. This arg indicates the font face to be used in the text displayed in the graph. The title is displayed using size +2, the tags and axis labels (see below) in normal size, and the max values at the head of graph bars in -1.
xlabel, ylabel: This args indicate the labels to be displayed on the base (x) and values (y) axis of the graph. Note: for a horizontal graph, the names of the axes are reversed as normal (ie the x axis is the vertical one).
xlabelalign: Default: center. This arg only has effect when a xlabel is specified, and it indicates the justification of the xlabel on the graph. Other valid values are left and right.
ylabelalign: Default: middle. This arg only has effect when a ylabel is specified, and it indicates the justification of the ylabel on the graph. Other valid values are top and bottom.
labeltextcolor: Default: black. This arg indicates a color for the xlabel and ylabel text.
labelbgcolor: Default: bgcolor. This arg indicates a background color for the row and column that contain the xlabel and ylabel.

TODO

: alternate background color for dataset rows/cols
: accept a formatting string for max values (for sprintf)
: showaxis
: support same size bars: ######___ 66%
: ranges in tags, and highlighttag/highlightpos to fit in a range
: accept args to specify the text height for title, tags, max vals
: trick so that ALT attrib of IMG tags are displayed in netscape/linux
: support for negative values (1 col/row for +, 1 col/row for -)
: implement an object oriented interface
: use HTML table building modules?
: test in IE

BUGS

: in several cases, the bars are not perfectly aligned (left for 'h' and bottom for 'v') and the values are written on the next line for 'h' graphics
: values are not middle "valigned" for 'h'/'bgcolor' graphics

AUTHOR

Vlad Podgurschi <cpan@podgurschi.org>

LICENSE

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