<?php
$im = imagecreate( 600, 600 );
$background= imagecolorallocate( $im, 25, 25, 75 );
imagefill( $im, 0,0, $background );
$white= imagecolorallocate( $im, 255, 255, 255 );

$a= array( 100, 200 );
$b= array( 200, 176 );
$c= array( 300, '' ); // This is to be calculated

imageline( $im, $a[0], $a[1], $c[0], $c[1], $white );

header("Content-Type: image/jpeg"); imagejpeg($im); exit();
?>