";

$cntrX = $width / 2;
$cntrY = $height / 2;
echo "
The center of the image is at " .$cntrX . ", " . $cntrY ;
echo '
Test Trig Fucntions php 
 Get all cordinates for a circle
';
$r = 5 ;
echo 'Radiuz == ' . $r . '
 X, Y, PixelColour at that point.

';

$im = imagecreatefromjpeg("spc.jpg");
$Pi = pi(); 
for ($a=0; $a<=360; $a++) {

   $ax =  $r*cos($a*$Pi/180) ; //x
   $ay =  $r*sin($a*$Pi/180) ; //y 
   $PXCol = imagecolorat($im, $ax, $ay);
   echo $ax . ", " . $ay . ", " . $PXCol . "
";
}
?>