Rotating a rectangle

[deanhystad]

You need to do a rotate and a move. The rotate you probably already have (I am not going to install pygame to verify). The move is not that bad. You could steal the code from Point.rotate_z.

    def rotate_z(self, angle, center=(0, 0, 0)):
        cx, cy, cz = center
        x = self.x - cx
        y = self.y - cy
        d = math.hypot(y, x)
        theta  = math.atan2(y, x) + angle
        self.x = cx + d * math.cos(theta)
        self.y = cy + d * math.sin(theta)

The self.x and self.y would be the center of the rectangle/image/surface/sail. The cx and cy the point about which you want the sail to rotate. It shouldn't be difficult to strip this code out of the class and make it a function.

As for the "black square", that is the background of the image/surface/sail. You need to make the background transparent