[X,Y] = GINPUT_ZOOM(N, STYLE) gets N points from the
current axes and returns the X- and Y-coordinates in
length N vectors X and Y. The style of cursor can be
change by setting STYLE (please refer to "Specifying
the Figure Pointer" in the help, default: 'fullcross').

User can click and drag to Zoom In / Out
- Left-Top to Right-Down means Zoom In
- Right-Down to left-Top means Zoom Out

[X,Y] = GINPUT_ZOOM gathers an unlimited number
(less then 100000) of points until the return key is pressed.

Others are same as GINPUT