NAME
    URI::GoogleChart - Generate Google Chart URIs

SYNOPSIS
     use URI::GoggleChart;
     my $chart = URI::GoogleChart->new("line", 300, 100,
         data => [45, 80, 100, 33],
     );

DESCRIPTION
    This module provide a constructor method for Google Chart URIs. Google
    will serve back PNG images of charts controlled by the provided
    parameters when these URI are dereferenced. Normally these URIs will be
    embedded as "<img src='$chart'>" tags in HTML documents.

    The Google Chart service is described at
    <http://code.google.com/apis/chart/> and these pages also define the API
    in terms of the parameters these URIs take. This module make it easier
    to generate URIs that conform to this API as it automatically takes care
    of data encoding and scaling, as well as hiding most of the cryptic
    parameter names that the API uses in order to generate shorter URIs.

    The following constructor method is provided:

    $uri = URI::GoogleChart->new( $type, $width, $height, %opt )
        The constructor method's 3 first arguments are mandatory and they
        define the type of chart to generate and the dimension of the image
        in pixels. The rest of the arguments are provided as key/value
        pairs. The return value is an HTTP URI object, which can also be
        treated as a string.

        The $type argument can either be one of the type code documented at
        the Google Charts page or one of the following more readable
        aliases:

            lines
            sparklines
            xy-lines

            horizontal-stacked-bars
            vertical-stacked-bars
            horizontal-grouped-bars
            vertical-grouped-bars

            pie
            pie-3d
            concentric-pie

            venn
            scatter-plot
            radar
            radar-splines
            google-o-meter

            world
            africa
            asia
            europe
            middle_east
            south_america
            usa

        The key/value pairs can either be one of the "chXXX" codes
        documented on the Google Chart pages or one of the following:

        data => [{ v => [$v1, $v2,...], %opt }, ...]
        data => [[$v1, $v2,...], [$v1, $v2,...], ...]
        data => [$v1, $v2,...]
        data => $v1
            The data to be charted is provided as an array of data series.
            Each series is defined by a hash with the "v" element being an
            array of data points in the series. Missing data points should
            be provided as "undef". Other hash elements can be provided to
            define various properties of the series. These are described
            below.

            As a short hand when you don't need to define other properties
            besides the data points you can just provide an array of numbers
            instead of the series hash.

            As a short hand when you only have a single data series, you can
            just provide a single array of numbers, and finally if you only
            have a single number you can provide it without wrapping it in
            an array.

            The following data series properties can be provided.

            The "group" property can be used to group data series together.
            Series that have the same group value belong to the same group.
            Values in the same group are scaled based on the minimum and
            maximum data point provided in that group. Data series without a
            "group" property belong to the default group.

        min => $num
        max => $num
            Defines the minimum and maximum value for the default group. If
            not provided the minimum and maximum is calculated from the data
            points belonging to this group. Chart types that plot relative
            values make the default minimum 0 so the relative size of the
            data points stay the same after scaling.

            The data points are scaled so that they are plotted relative to
            the ($min .. $max) range. For example if the ($min .. $max)
            range is (5 .. 10) then a data point value of 7.5 is plotted in
            the middle of the chart area.

        group => { $name => { min => $min, max => $max }, ...},
            Define parameters for named data series groups. Currently you
            can only set up the minimum and maximum values used for scaling
            the data points.

        encoding => "t"
        encoding => "s"
        encoding => "e"
            Select what kind of data encoding you want to be used. They
            differ in the resolution they provide and in their readability
            and verbosity. Resolution matters if you generate big charts.
            Verbosity matters as some web client might refuse to dereference
            URLs that are too long.

            The "t" encoding is the most readable and verbose. It might
            consume up to 5 bytes per data point. It provide a resolution of
            1/1000.

            The "s" encoding is the most compact; only consuming 1 byte per
            data point. It provide a resolution of 1/62.

            The "e" encoding provides the most resolution and it consumes 2
            bytes per data point. It provide a resolution of 1/4096.

            The default encoding is currently "t"; but expect this to
            change. The default ought to be automatically selected based on
            the resolution of the chart and the number of data points
            provided.

        color => $color
        color => [$color1, $color2, ...]
            Sets the colors to use for charting the data series. The
            canonical form for $color is hexstrings either of "RRGGBB" or
            "RRGGBBAA" form. When you use this interface you might also use
            "RGB" form as well as some comon names like "red", "blue",
            "green", "white", "black",... which are expanded to the
            canonical form in the URI.

        title => $str
        title => { text => $str, color => $color, fontsize => $fontsize }
            Sets the title for the chart; optionally changing the color and
            fontsize used for the title.

        margin => $num
        margin => { left => $n, right => $n, top => $n, bottom => $n }
            Sets the chart margins in pixels. If a single number is provided
            then all the margins are set to this number of pixels.

SEE ALSO
    <http://code.google.com/apis/chart/>

    URI

COPYRIGHT AND LICENSE
    Copyright 2009 Gisle Aas.

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

