chart_function.php

<?php
 function chart_data($values) {

// Port of JavaScript from http://code.google.com/apis/chart/
// http://james.cridland.net/code
// First, find the maximum value from the values given

                    $maxValue = max($values);

// A list of encoding characters to help later, as per Google's example
                    $simpleEncoding = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';

                    $chartData = "s:";
                    for ($i = 0; $i < count($values); $i++) {
                        $currentValue = $values[$i];

                        if ($currentValue > -1) {
                            $chartData.=substr($simpleEncoding, 61 * ($currentValue / $maxValue), 1);
                        } else {
                            $chartData.='_';
                        }
                    }

// Return the chart data - and let the Y axis to show the maximum value
                    return $chartData . "&chxt=x,x";
                }
?>