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| -rw-r--r-- | engine/lib/tags.php | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/engine/lib/tags.php b/engine/lib/tags.php new file mode 100644 index 000000000..9b675c018 --- /dev/null +++ b/engine/lib/tags.php @@ -0,0 +1,68 @@ +<?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) + { + $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); + + return $cloud; + } +?>
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