Dynamic mask

1

hello I have a dynamic mask action code written below, can anyone help me edit this code so that it only reveals images on mouse press. Right now it automatically reveals images on mouse over.

onClipEvent(load)
{
_root.createEmptyMovieClip(‘square’,0);
function drawSquare()
{
x = _root._xmouse;
y = _root._ymouse;
with(_root.square)
{

                    moveTo(x-10,y-10);
                    beginFill(0x000088)
                    lineTo(x+10,y-10);
                    lineTo(x+10,y+10);
                    lineTo(x-10,y+10);
                    endFill();
            }
    }
    this.setMask (_root.square)

}
onClipEvent(mouseMove)
{
drawSquare();
updateAfterEvent();
}