【求助】如何实现选择图片中的任意形状的一部分

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

RECT = GETRECT(AX) lets you select a rectangle in the axes
specified by the handle AX.

See also GETLINE, GETPTS.