The routine gSetAlphaMode() switches non-windowing graphical devices into alphanumeric mode so that the user may read from or write to them via I/O systems other than GINO.
The routine gSetAlphaMode() forces out any graphic data held in device buffers, stores the current position, and selects character mode.
When the next GINO routine is called the stored current drawing position is restored and drawing may continue.
