this is what I"m using now

var rectangle = new google.maps.Rectangle( {
                strokeColor : "-sharpFF0000",
                strokeOpacity : 0.8,
                strokeWeight : 0,
                fillColor : "-sharp575757",
                fillOpacity : 0.35,
                map : map,
                bounds : new google.maps.LatLngBounds(new google.maps.LatLng(
                        minusXY(pointO.y, h), minusXY(pointO.x, d * 6)),//C
                        new google.maps.LatLng(minusXY(pointO.y, h * 3),
                                plusXY(pointO.x, d * 6))//D
                )

});

draws a rectangle, but now you want to draw a rectangle with rounded corners, how do you draw it? Check the official api there are only a few kinds of drawing rectangular circular polygon lines, I just want to add rounded corners to the rectangle on the current basis, how should this be changed?