GD Transparent Cutout

[jeff205]

I am using the following code to give my image round corners, but i am using an image that just cuts the corner with a white shape. Is it possible to make it cut the corner with a transparent color?

 

function roundcorners($image, $topleft, $topright = null, $bottomright = null, $bottomleft = null) {
		if($topright == null) $topright = $topleft;
		if($bottomright == null) $bottomright = $topleft;
		if($bottomleft == null) $bottomleft = $topleft;
		if($topleft >= 2) {
			$tl = imagecreatefrompng("corner.png");
			imagecopyresampled($image, $tl, 0, 0, 0, 0, $topleft, $topleft, 485, 485);
		}
		if($topright >= 2) {
			$tr = imagerotate(imagecreatefrompng("corner.png"), 270, 0);
			imagecopyresampled($image, $tr, imagesx($image)-$topright, 0, 0, 0, $topright, $topright, 485, 485);
		}
		if($bottomright >= 2) {
			$br = imagerotate(imagecreatefrompng("corner.png"), 180, 0);
			imagecopyresampled($image, $br, imagesx($image)-$bottomright, imagesy($image)-$bottomright, 0, 0, $bottomright, $bottomright, 485, 485);
		}
		if($bottomleft >= 2) {
			$bl = imagerotate(imagecreatefrompng("corner.png"), 90, 0);
			imagecopyresampled($image, $bl, 0, imagesy($image)-$bottomleft, 0, 0, $bottomleft, $bottomleft, 485, 485);
		}
	}