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<?php
/**
* Elgg tags
* Functions for managing tags and tag clouds.
*
* @package Elgg
* @subpackage Core
* @license http://www.gnu.org/licenses/old-licenses/gpl-2.0.html GNU Public License version 2
* @author Marcus Povey <marcus@dushka.co.uk>
* @copyright Curverider Ltd 2008
* @link http://elgg.org/
*/
/**
* The algorithm working out the size of font based on the number of tags.
* This is quick and dirty.
*/
function calculate_tag_size($min, $max, $number_of_tags, $buckets = 6)
{
$delta = (($max - $min) / $buckets);
$thresholds = array();
for ($n=1; $n <= $buckets; $n++) {
$thresholds[$n-1] = ($min + $n) * $delta;
}
// Correction
if ($thresholds[$buckets-1]>$max) $thresholds[$buckets-1] = $max;
$size = 0;
for ($n = 0; $n < count($thresholds); $n++) {
if ($number_of_tags >= $thresholds[$n])
$size = $n;
}
return $size;
}
/**
* This function generates an array of tags with a weighting.
*
* @param array $tags The array of tags.
* @return An associated array of tags with a weighting, this can then be mapped to a display class.
*/
function generate_tag_cloud(array $tags, $buckets = 6)
{
$cloud = array();
$min = 65535;
$max = 0;
foreach ($tags as $tag)
{
$cloud[$tag]++;
if ($cloud[$tag]>$max) $max = $cloud[$tag];
if ($cloud[$tag]<$min) $min = $cloud[$tag];
}
foreach ($cloud as $k => $v)
$cloud[$k] = calculate_tag_size($min, $max, $v, $buckets);
return $cloud;
}
?>
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