//определяем тип: вертикальный или горизонтальный$type = (isset($_GET['type']) && $_GET['type'] == 'g') ? 'g' : 'v';//определяем высоту$height = (isset($_GET['h'])) ? intval($_GET['h']) : 100;//определяем ширину$width = (isset($_GET['w'])) ? intval($_GET['w']) : 60;//определяем цвета$start = (isset($_GET['s']) && preg_match('#[0-9A-F]{6}#',$_GET['s'])) ? $_GET['s'] : '000000';$end = (isset($_GET['e']) && preg_match('#[0-9A-F]{6}#',$_GET['e'])) ? $_GET['e'] : 'FFFFFF';//определяем RGB этих цветов$start_r= hexdec(substr($start, 0, 2));$start_g = hexdec(substr($start, 2, 2));$start_b = hexdec(substr($start, 4, 2));$end_r = hexdec(substr($end, 0, 2));$end_g = hexdec(substr($end, 2, 2));$end_b = hexdec(substr($end, 4, 2));//создаём картинку$image = imagecreate($width, $height);//определяем тип и рисуем градиентif($type == 'g'){

   for($x=0; $x<$width; $x  ){

    $new_r = $start_r - intval(($start_r - $end_r) / $width * $x);    $new_g = $start_g - intval(($start_g - $end_g) / $width * $x);    $new_b = $start_b - intval(($start_b - $end_b) / $width * $x);    $row_color = imagecolorresolve($image, $new_r, $new_g, $new_b);    imageline($image, $x, 0, $x, $height, $row_color);    }}else{

  for($y=0; $y<$height; $y  ){

    $new_r = $start_r - intval(($start_r - $end_r) / $height * $y);        $new_g = $start_g - intval(($start_g - $end_g) / $height * $y);        $new_b = $start_b - intval(($start_b - $end_b) / $height * $y);        $row_color = imagecolorresolve($image, $new_r, $new_g, $new_b);        imageline($image, 0, $y, $width, $y, $row_color);        }}header('Content-type: image/png');imagepng($image);imagedestroy($image);