astGrfPushastGrfPush - Save the current graphics functions used by a Plot

Description:
This function takes a snapshot of the graphics functions which are currently registered with the supplied PlotPlot, and saves the snapshot on a first-in-last-out stack within the Plot. The snapshot can be restored later using function astGrfPopastGrfPop.

The astGrfPush and astGrfPop functions are intended for situations where it is necessary to make temporary changes to the graphics functions used by the Plot. The current functions should first be saved by calling astGrfPush. New functions should then be registered using astGrfSetastGrfSet. The required graphics should then be produced. Finally, astGrfPop should be called to restore the original graphics functions.

Synopsis:
void astGrfPush( AstPlot $*$this )
Parameters:
this
Pointer to the Plot.