Setting the SGS coordinates to match an AUTOGRAPH plot

Once AUTOGRAPH has established its plotting strategy (usually after drawing the graph, or either the background or curve) it may be necessary to make additions to the plot or to perform input. This can be done conveniently as follows:

      Plot the graph with AUTOGRAPH
      CALL SNX_AGCS

The call to SNX_AGCS sets the extent (in world coordinates) of the current SGS zone, presumed to cover the AUTOGRAPH graph window (the rectangular area within which the whole AUTOGRAPH plot, including labels etc., is drawn), so that the AUTOGRAPH grid window (the rectangular area within which the curve itself is plotted) has bounds (0.0,1.0,0.0,1.0). Thus the world coordinates of the SGS zone are now AUTOGRAPH grid coordinates. Clipping requirements may then make it necessary to create another zone covering just the grid window, but still with grid coordinates. This is easily accomplished by:

      CALL SGS_ZONE( 0.0, 1.0, 0.0, 1.0, IZGW, J )
      CALL SGS_SW( 0.0, 1.0, 0.0, 1.0, J )