ZINPUT - Graphical input from mouse with zoom

[OUT_REGS] = ZINPUT(N) gets N points or regions from the current axes and returns the X- and Y-ranges in a length Nx4 matrix OUT_REGS.
The cursor can be positioned using the mouse. Data points are entered by pressing the right mouse button (OUT_REGS(1)==OUT_REGS(2)==point_X), the region of the current axis are selected with the middle button, left button is for zooming, single cklick zooms in, click-and drag zooms to selected region (and doubble-click should zoom out - this feature is pending).
Any key on the keyboard except carriage return zooms out to the orignal axis. Carriage return/Enter, which terminates the input before N points are entered.

[OUT_REGS] = ZINPUT gathers an unlimited number of points until the return key is pressed.