public function __construct(array $track)
{
$x = $track['x'];
$y = $track['y'];
$c = $track['c'];
// Ensure real arrays
if (!is_array($x)) {
$x = explode(",", $x);
}
if (!is_array($y)) {
$y = explode(",", $y);
}
if (!is_array($c)) {
$c = explode(",", $c);
}
$f = (int) $track['f'];
$n = count($x);
$distCoords = convert_points($x, $y, true);
// Distance study
$dc_x = array();
$dc_y = array();
foreach ($x as $j => $val) {
if ($j >= $n - 1) {
break;
}
$dx = abs($x[$j] - $x[$j + 1]);
$dy = abs($y[$j] - $y[$j + 1]);
$dc_x[] = $dx;
$dc_y[] = $dy;
$dc_t[] = $dx * $dx + $dy * $dy;
}
// Kinematics study
$stop = 0;
foreach ($distCoords as $dist) {
if ($dist > 0) {
continue;
}
++$stop;
}
$clean_x = array_unique($x);
$clean_y = array_unique($y);
// Horizontal components
$entry_x = $x[0];
$exit_x = $x[$n - 1];
$min_x = min($clean_x);
$max_x = max($clean_x);
$range_x = $max_x - $min_x;
$scroll_x = 100 * round($range_x / $track['w'], 4);
$centroid_x = array_avg($clean_x);
$len_x = array_sum($dc_x);
$dist_x = array_avg($dc_x);
// Vertical components
$entry_y = $y[0];
$exit_y = $y[$n - 1];
$min_y = min($clean_y);
$max_y = max($clean_y);
$range_y = $max_y - $min_y;
$scroll_y = 100 * round($range_y / $track['h'], 4);
$centroid_y = array_avg($clean_y);
$len_y = array_sum($dc_y);
$dist_y = array_avg($dc_y);
// Total components
$dist_t = array_avg($dc_t);
$len_t = array_sum($dc_t);
// save features
$this->time = round($n / $f, 2);
$this->numClicks = count_clicks($c);
$this->activity = 100 * (1 - round($stop / count($distCoords), 4));
$this->entry = array('x' => $entry_x, 'y' => $entry_y);
$this->exit = array('x' => $exit_x, 'y' => $exit_y);
$this->range = array('x' => $range_x, 'y' => $range_y);
$this->scrollReach = array('x' => $scroll_x, 'y' => $scroll_y);
$this->centroid = array('x' => $centroid_x, 'y' => $centroid_y);
$this->trackLen = array('x' => $len_x, 'y' => $len_y, 't' => $len_t);
$this->distance = array('x' => $dist_x, 'y' => $dist_y, 't' => $dist_t);
}
// check Flash client request
if ($_POST['xhr']) {
require '../../../../config.php';
$xcoords = json_decode($_POST['xdata']);
$ycoords = json_decode($_POST['ydata']);
} else {
// transform mouse coordinates in a real PHP array
$xcoords = explode(",", $coordsX);
$ycoords = explode(",", $coordsY);
}
if (!count(array_sanitize($xcoords)) && !$_POST['xhr']) {
die("<strong>Error</strong>: No mouse data.");
}
// transform arrays in a single points array
$pointArray = convert_points($xcoords, $ycoords);
// We can do as many clusters as (to the extreme) the sample points size,
// so better use the rule of thumb: k ~ sqrt(n/2)
$n = count($pointArray);
$k = ceil(sqrt($n / 2));
$km = new KMeans($pointArray, $k);
$km->initKatsavounidis();
$km->doCluster();
foreach ($km->clusters as $i => $cluster) {
$size = count($cluster);
// exclude singleton clusters
if ($size < 2) {
continue;
}
$clusterSize[] = $size;
// round cluster centers for better drawing