The 'onResize' callback

Event number: 12
Generated for: Any visible object (usually windows)

The onResize callback is called when the user resizes a window, or when your program calls the Resize method. The event-specific parameters in ⎕EV apply to a Window, Form, Dialog, or Document only and are (in index origin 1):

        ⎕EV[6]        New width in pixel units
        ⎕EV[7]        New height in pixel units

Note that this callback is not invoked if your program changes an object's size by setting the size or where property - you need to call the Resize method as well if you want the callback function to be run.

In older APL systems, this callback was frequently used to re-arrange the controls in a window to reflect the re-sizing. In APLX, you can often do this much more simply by specifying the align or anchors properties of the controls in the window.