x=ginput(4)

用getrect（）函数看看行吗！<BR>GETRECT Select rectangle with mouse.<BR>    RECT = GETRECT(FIG) lets you select a rectangle in the<BR>    current axes of figure FIG using the mouse.  Use the mouse to<BR>    click and drag the desired rectangle.  RECT is a four-element<BR>    vector with the form [xmin ymin width height].  To constrain<BR>    the rectangle to be a square, use a shift- or right-click to<BR>    begin the drag.<BR> <BR>    RECT = GETRECT(AX) lets you select a rectangle in the axes<BR>    specified by the handle AX.<BR> <BR>    See also GETLINE, GETPTS.