There is a simple function to draw a filled point with a chosen radius and color.
<?php
function drawPoint($img, $radius, $origo_x, $origo_y, $pointColor)
{
for ($i=0;$i<=360;$i++)
{
$pont[] = $origo_x + ($radius * sin(deg2rad($i)));
$pont[] = $origo_y - ($radius * cos(deg2rad($i)));
}
reset($pont);
ImageFilledPolygon ($img, $pont, (sizeof($pont)/2), $pointColor);
}
?>