functions in graph.i - g

             gridxy, flag  
          or gridxy, xflag, yflag  
 
     Turns on or off grid lines according to FLAG.  In the first form, both  
     the x and y axes are affected.  In the second form, XFLAG and YFLAG  
     may differ to have different grid options for the two axes.  In either  
     case, a FLAG value of 0 means no grid lines (the default), a value of  
     1 means grid lines at all major ticks (the level of ticks which get  
     grid lines can be set in the style sheet), and a FLAG value of 2 means  
     that the coordinate origin only will get a grid line.  In styles with  
     multiple coordinate systems, only the current coordinate system is  
     affected.  
     The keywords can be used to affect the style of the grid lines.  
     You can also turn the ticks off entirely.  (You might want to do this  
     to plot your own custom set of tick marks when the automatic tick  
     generating machinery will never give the ticks you want.  For example  
     a latitude axis in degrees might reasonably be labeled "0, 30, 60,  
     90", but the automatic machinery considers 3 an "ugly" number - only  
     1, 2, and 5 are "pretty" - and cannot make the required scale.  In  
     this case, you can turn off the automatic ticks and labels, and use  
     plsys, pldj, and plt to generate your own.)  
     To fiddle with the tick flags in this general manner, set the  
     0x200 bit of FLAG (or XFLAG or YFLAG), and "or-in" the 0x1ff bits  
     however you wish.  The meaning of the various flags is described  
     in the file Y_SITE/gist/work.gs.  Additionally, you can use the  
     0x400 bit to turn on or off the frame drawn around the viewport.  
     Here are some examples:  
        gridxy,0x233        work.gs default setting  
        gridxy,,0x200       like work.gs, but no y-axis ticks or labels  
        gridxy,,0x231       like work.gs, but no y-axis ticks on right  
        gridxy,0x62b        boxed.gs default setting  
     The three keywords base60=, degrees=, and hhmm= can be used to get  
     alternative tick intervals for base 60 systems instead of the  
     usual base 10 systems.  The keyword values are 0 to restore the  
     default behavior, 1 to set the feature for the x axis, 2 to set it  
     for the y axis, and 3 to set it for both axes.  The base60 feature  
     allows ticks and labels at multiples of 30 (up to +-3600).  The  
     degrees feature causes labels to be printed modulo 360 (so that a  
     scale which runs from, say, 90 to 270 will be printed as 90 to 180  
     then -180 to -90, mostly for longitude scales).  The hhmm feature  
     causes labels to be printed in the form hh:mm (so that, for example,  
     150 will be printed as 02:30, mostly for time of day scales).  
   KEYWORDS: color, type, width, base60, degrees, hhmm  
builtin function, documented at i0/graph.i   line 794