36 lines
1.3 KiB
PHP
36 lines
1.3 KiB
PHP
<?php
|
|
/*
|
|
PHPlot / contrib / prune_labels
|
|
$Id: prune_labels.php 454 2009-12-09 03:45:55Z lbayuk $
|
|
PHPlot contrib code - public domain - no copyright - use as you wish
|
|
|
|
Reduce the number of data labels along the X axis, when the density is too
|
|
high. This simply blanks out M-1 of every M labels in the data array.
|
|
There are other ways to do this, but we need to keep the labels uniformly
|
|
spaced. You select the target maximum label count (maxlabels), and you will
|
|
get no more than maxlabels data labels.
|
|
|
|
Arguments:
|
|
$data - The PHPlot data array (reference variable)
|
|
$maxlabels - The maximum number of data labels you are willing to have,
|
|
Returns: Nothing
|
|
Modifies the $data array in place to remove some of the labels.
|
|
|
|
Notes:
|
|
The data array and its rows must be 0-based integer indexed arrays.
|
|
*/
|
|
function prune_labels(&$data, $maxlabels)
|
|
{
|
|
# Do nothing if there are not already too many labels:
|
|
if (($n = count($data)) <= $maxlabels) return;
|
|
|
|
# Compute how many labels to erase. Keep 1 of every $m labels.
|
|
$m = (int)ceil($n / $maxlabels);
|
|
|
|
# Process the data array, zapping M-1 of every M labels:
|
|
$k = 0;
|
|
for ($i = 0; $i < $n; $i++) {
|
|
if ($k > 0) $data[$i][0] = '';
|
|
if (++$k >= $m) $k = 0;
|
|
}
|
|
}
|