functions in graph.i -

             animate  
          or animate, 0/1  
 
     without any arguments, toggles animation mode; with argument 0,  
     turns off animation mode, with argument 1 turns on animation mode.  
     In animation mode, the X window associated with a graphics window  
     is actually an offscreen pixmap which is bit-blitted onscreen  
     when an fma command is issued.  This is confusing unless you are  
     actually trying to make a movie, but results in smoother animation  
     if you are.  Generally, you should turn animation on, run your movie,  
     then turn it off.  

 arrowl  
 

 arroww  
 

 aspect  
 

             bytscl(z)  
          or bytscl(z, top=max_byte, cmin=lower_cutoff, cmax=upper_cutoff)  
 
     returns a char array of the same shape as Z, with values linearly  
     scaled to the range 0 to one less than the current palette size.  
     If MAX_BYTE is specified, the scaled values will run from 0 to  
     MAX_BYTE instead.  
     If LOWER_CUTOFF and/or UPPER_CUTOFF are specified, Z values outside  
     this range are mapped to the cutoff value; otherwise the linear  
     scaling maps the extreme values of Z to 0 and MAX_BYTE.  

             closed=   plotting keyword  
          or smooth=   plotting keyword  
 
     selects closed curves (closed=1) or default open curves (closed=0),  
     or Bezier smoothing (smooth>0) or default piecewise linear curves  
     (smooth=0).  The value of smooth can be 1, 2, 3, or 4 to get  
     successively more smoothing.  Only the Bezier control points are  
     plotted to an X window; the actual Bezier curves will show up in  
     PostScript hardcopy files.  Closed curves join correctly, which  
     becomes more noticeable for wide lines; non-solid closed curves  
     may look bad because the dashing pattern may be incommensurate  
     with the length of the curve.  
   PLOTTING COMMANDS: plg, plc (smooth only)  

             color=   plotting keyword  
 
     selects line or text color.  Valid values are the strings "bg", "fg",  
     "black", "white", "red", "green", "blue", "cyan", "magenta", "yellow",  
     or a 0-origin index into the current palette.  The default is "fg".  
     Negative numbers may be used instead of the strings: -1 is bg  
     (background), -2 is fg (foreground), -3 is black, -4 is white,  
     -5 is red, -6 is green, -7 is blue, -8 is cyan, -9 is magenta, and  
     -10 is yellow.  (The negative numbers are actually taken modulo  
     256, so -1 is also 255, -2 is 254, and so on.)  
     A color can also be a triple [r, g, b], with values running from  
     0 for dark to 255 for full intensity.  Beware, however, of  
     specifying an rgb color (either as a color keyword or to the  
     plf, pli, or plfp commands) if your display is not a true color  
     display (for example, if it is 8 bits deep or less).  In that  
     case, it may switch to a 5x9x5 color cube, which causes a  
     significant degradation in quality of rendering with smooth  
     color palettes.  Furthermore, the hcp command will not work  
     properly for rgb colors if the file is a CGM.  Use the rgb=1  
     keyword in the window command to avoid having to re-issue a  
     palette command after the first rgb object is drawn (this is  
     unnecessary on true color screens).  
   PLOTTING COMMANDS: plg, plm, plc, pldj, plt  

             color_bar  
          or color_bar, levs, colors  
 
     Draw a color bar below the current coordinate system.  If LEVS is  
     not specified uses plfc_levs (set by previous call to plfc).  If  
     COLORS is specified, it should have one more value than LEVS,  
     otherwise equally spaced colors are chosen, or plfc_colors if  
     plfc_levs was used.  With the vert=1 keyword the color bar appears  
     to the left of the current coordinate system (vert=0 is default).  
     By default, color_bar will attempt to label some of the color  
     interfaces.  With the labs= keyword, you can force the labelling  
     algorithm as follows: labs=0 supresses all labels, labs=n forces  
     a label at every nth interface, labs=[i,n] forces a label at every  
     nth interface starting from interface i (0<=i<=numberof(LEVS)).  
     You can use the adjust= keyword to move the bar closer to (adjust<0)  
     or further from (adjust>0) the viewport, and the height= keyword to  
     set the height of any labels (default 14 points).  

             nc= contour(yc,xc, level, z, y,x)  
          or nc= contour(yc,xc, level, z, y,x,ireg)  
 
     returns the points on the contour curve that would have been  
     plotted by plc.  Z, Y, X, and IREG are as for plc, and the  
     triangle= and region= keywords are accepted and have the same  
     meaning as for plc.  Unlike plc, the triangle array is an output  
     as well as an input to contour; if supplied it may be modified  
     to reflect any triangulations which were performed by contour.  
     LEVEL is a scalar z value to return the points at that contour  
     level.  All such points lie on edges of the mesh.  If a contour  
     curve closes, the final point is the same as the initial point  
     (i.e.- that point is included twice in the returned list).  
     LEVEL is a pair of z values [z0,z1] to return the points of  
     a set of polygons which outline the regions between the two  
     contour levels.  These will include points on the mesh boundary  
     which lie between the levels, in addition to the edge points  
     for both levels.  The polygons are closed, simply connected,  
     and will not contain more than about 4000 points (larger polygons  
     are split into pieces with a few points repeated where the pieces  
     join).  
     YC and XC are the output points on the curve(s), or nil if there  
     are no points.  On input, they must be simple variable references,  
     not expressions.  The return value NC is a list of the lengths of  
     the polygons/polylines returned in (XC,YC), or nil if there are  
     none.  numberof(XC)==numberof(YC)==sum(NC).  For the level pair  
     case, YC, XC, and NC are ready to be used as inputs to plfp.  
   KEYWORDS: triangle, region  

             current_mouse();  
 
       -or- current_mouse(win);  
       -or- focused_window();  
       -or- has_mouse();  
       -or- has_mouse(win);  
     The function current_mouse returns the pointer position in the  
     graphics window with pointer focus as an array of double's in the  
     form [X,Y,SYS,WIN] where X and Y are the pointer coordinates in  
     the coordinate system SYS and WIN is the number of the graphics  
     window.  If no graphics window currently has the pointer focus or  
     if WIN is specified but does not match the graphics window with  
     pointer focus, the result is empty.  
     The function focused_window returns the number of the graphics  
     window with pointer focus, or -1 if none.  
     The function has_mouse with a void argument returns true if any  
     Yorick graphics window has the pointer focus. If WIN is  
     specified, the function has_mouse returns true if graphics window  
     WIN has the pointer focus.  
     Note that the window which has the pointer focus may be different  
     from the so-called current window to which graphics commands are  
     directed.  The built-in functions `window' and `current_window'  
     (which see) can be used to set/query the current window.  
   

             n= current_window()  
 
     returns the number of the current graphics window, or -1 if none.  

 ecolor  
 

             edges=   plotting keyword  
          or ecolor=   plotting keyword  
          or ewidth=   plotting keyword  
 
     set the appearance of zone edges in a filled mesh plot (plf or plfp).  
     By default, edges=0, and the zone edges are not plotted.  If  
     edges=1, a solid line is drawn around each zone after it is  
     filled; the edge color and width are given by ecolor and ewidth,  
     which are "fg" and 1.0 by default.  
   PLOTTING COMMANDS: plf  

             eps, name  
 
     writes the picture in the current graphics window to the Encapsulated  
     PostScript file NAME+".eps" (i.e.- the suffix .eps is added to NAME).  
     This function requires ghostscript.  Any hardcopy file associated with  
     the current window is first closed, but the default hardcopy file is  
     unaffected.  As a side effect, legends are turned off and color table  
     dumping is turned on for the current window.  
     The external variable EPSGS_CMD contains the command to start  
     ghostscript.  

             eps, name  
 
     writes the picture in the current graphics window to the Encapsulated  
     PostScript file NAME+".epsi" (i.e.- the suffix .epsi is added to NAME).  
     The eps function requires the ps2epsi utility which comes with the  
     project GNU Ghostscript program.  Any hardcopy file associated with  
     the current window is first closed, but the default hardcopy file is  
     unaffected.  As a side effect, legends are turned off and color table  
     dumping is turned on for the current window.  
     The external variable PS2EPSI_FORMAT contains the format for the  
     command to start the ps2epsi program.  

 ewidth  
 

             fma  
 
     frame advance the current graphics window.  The current picture  
     remains displayed in the associated X window until the next element  
     is actually plotted.  

 focused_window  
 

             font=     plotting keyword  
          or height=   plotting keyword  
          or opaque=   plotting keyword  
          or orient=   plotting keyword  
          or justify=  plotting keyword  
 
     selects text properties.  The font can be any of the strings  
     "courier", "times", "helvetica" (the default), "symbol", or  
     "schoolbook".  Append "B" for boldface and "I" for italic, so  
     "courierB" is boldface Courier, "timesI" is Times italic, and  
     "helveticaBI" is bold italic (oblique) Helvetica.  Your X server  
     should have the Adobe fonts (available free from the MIT X  
     distribution tapes) for all these fonts, preferably at both 75  
     and 100 dpi.  Occasionally, a PostScript printer will not be  
     equipped for some fonts; often New Century Schoolbook is missing.  
     The font keyword may also be an integer: 0 is Courier, 4 is Times,  
     8 is Helvetica, 12 is Symbol, 16 is New Century Schoolbook, and  
     you add 1 to get boldface and/or 2 to get italic (or oblique).  
     The height is the font size in points; 14.0 is the default.  
     X windows only has 8, 10, 12, 14, 18, and 24 point fonts, so  
     don't stray from these sizes if you want what you see on the  
     screen to be a reasonably close match to what will be printed.  
     By default, opaque=0 and text is transparent.  Set opaque=1 to  
     white-out a box before drawing the text.  The default orient  
     (orient=0) is left-to-right text; set orient=1 for text rotated 90  
     degrees so it reads upward, orient=2 for 180 degree rotation so  
     it is upside down, and orient=3 for 270 degree rotation so it  
     reads downward.  
     The default text justification, justify="NN" is normal is both  
     the horizontal and vertical directions.  Other possibilities  
     are "L", "C", or "R" for the first character, meaning left,  
     center, and right horizontal justification, and "T", "C", "H",  
     "A", or "B", meaning top, capline, half, baseline, and bottom  
     vertical justification.  The normal justification "NN" is equivalent  
     to "LA".  Common values are "LA", "CA", and "RA" for garden variety  
     left, center, and right justified text, with the y coordinate at the  
     baseline of the last line in the string presented to plt.  The  
     characters labeling the right axis of a plot are "RH", so that the  
     y value of the text will match the y value of the corresponding  
     tick.  Similarly, the characters labeling the bottom axis of a plot  
     are "CT".  The justify= may also be a number, horizontal+vertical,  
     where horizontal is 0 for "N", 1 for "L", 2 for "C", or 3 for "R",  
     and vertical is 0 for "N", 4 for "T", 8 for "C", 12 for "H",  
     16 for "A", or 20 for "B".  
   PLOTTING COMMANDS: plt  

             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  

 has_mouse  
 

             hcp  
             hcpon  
             hcpoff  
 
     The hcp command sends the picture displayed in the current graphics  
     window to the hardcopy file.  (The name of the default hardcopy file  
     can be specified using hcp_file; each individual graphics window may  
     have its own hardcopy file as specified by the window command.)  
     The hcpon command causes every fma (frame advance) command to do  
     and implicit hcp, so that every frame is sent to the hardcopy file.  
     The hcpoff command reverts to the default "demand only" mode.  

             hcp_file, filename, dump=0/1, ps=0/1  
 
     sets the default hardcopy file to FILENAME.  If FILENAME ends with  
     ".cgm", the file will be a binary CGM, otherwise it will be a  
     Postscript file.  By default, the hardcopy file name will be  
     "Aa00.ps", or "Ab00.ps" if that exists, or "Ac00.ps" if both  
     exist, and so on.  The default hardcopy file gets hardcopy from all  
     graphics windows which do not have their own specific hardcopy file  
     (see the window command).  If the dump keyword is present and non-zero,  
     the current palette will be dumped at the beginning of each frame  
     of the default hardcopy file (default behavior).  With dump=0,  
     all colors are converted to a gray scale, and the output files are  
     smaller because no palette information is included.  
     Use ps=0 to make "Aa00.cgm", "Ab00.cgm", etc by default instead of  
     Postscript.  
     The dump= and ps= settings persist until explicitly changed by a  
     second call to hcp_file; the dump=1 setting becomes the default for  
     the window command as well.  

             filename= hcp_finish()  
          or filename= hcp_finish(n)  
 
     closes the current hardcopy file and returns the filename.  
     If N is specified, closes the hcp file associated with window N  
     and returns its name; use hcp_finish(-1) to close the default  
     hardcopy file.  

             hcp_out  
          or hcp_out, n  
 
     finishes the current hardcopy file and sends it to the printer.  
     If N is specified, prints the hcp file associated with window N;  
     use hcp_out,-1 to print the default hardcopy file.  
     Unless the KEEP keyword is supplied and non-zero, the file will  
     be deleted after it is processed by gist and sent to lpr.  

 hcpoff  
 

 hcpon  
 

             hcps, name  
 
     writes the picture in the current graphics window to the  
     PostScript file NAME+".ps" (i.e.- the suffix .ps is added to NAME).  
     Legends are not written, but the palette is always dumped.  

 height  
 

             hide=   plotting keyword  
 
     sets the visibility of a plotted element.  The default is hide=0,  
     which means that the element will be visible.  Use hide=1 to remove  
     the element from the plot (but not from the display list).  
   PLOTTING COMMANDS: plg, plm, plc, plv, plf, pli, plt, pldj  

             histeq_scale(z, top=top_value, cmin=cmin, cmax=cmax)  
 
     returns a byte-scaled version of the array Z having the property  
     that each byte occurs with equal frequency (Z is histogram  
     equalized).  The result bytes range from 0 to TOP_VALUE, which  
     defaults to one less than the size of the current palette (or  
     255 if no pli, plf, or palette command has yet been issued).  
     If non-nil CMIN and/or CMAX is supplied, values of Z beyond these  
     cutoffs are not included in the frequency counts.  

             hollow=   plotting keyword  
          or aspect=   plotting keyword  
 
     set the appearance of the "darts" of a vector field plot.  The  
     default darts, hollow=0, are filled; use hollow=1 to get just the  
     dart outlines.  The default is aspect=0.125; aspect is the ratio  
     of the half-width to the length of the darts.  Use the color  
     keyword to control the color of the darts.  
   PLOTTING COMMANDS: plv  

             jpeg, name  
 
     writes the picture in the current graphics window to the JPEG  
     file NAME+".jpg" (i.e.- the suffix .jpg is added to NAME).  The  
     jpeg file is intended to be imported into MS PowerPoint or other  
     commercial presentation software.  This function starts ghostscript  
     using the EPSGS_CMD variable.  With the gray=1 keyword, you get  
     the jpeggray ghostscript device, otherwise jpeg.  
     The default yorick graphics window is 6 inches square, and by  
     default png produces 72 dpi (dot per inch) output.  You can change  
     this with the dpi= keyword; dpi=300 is extremely high resolution.  

 justify  
 

             keybd_focus, on_off  
 
     By default, graphics windows set a window manager hint which  
     allows them to accept keyboard focus.  With ON_OFF zero, that  
     hint will not be set when a new graphics window is created.  
     This causes the window manager to refuse to offer keyboard  
     focus to the graphics window -- very desirable, since it can't  
     accept keyboard input anyway.  With fvwm, for example, this  
     means keyboard focus can stay in the terminal window even when  
     you are mouse zooming the graphics window.  However, many  
     window managers confuse colormap focus with keyboard focus, so  
     if you set the private=1 colormap in the window function, you  
     may not be able to convince the window manager to give the  
     graphics window colormap focus since it won't give it keyboard  
     focus.  Weird.  

             legend=   plotting keyword  
 
     sets the legend for a plot.  The default legend is a concatentation  
     of the strings used in the original plotting command (plg, plm, etc.),  
     except for the plt command, which has no default legend.  
     Legends are never plotted to the X window; use the plq command to  
     see them interactively.  Legends will appear in hardcopy output  
     unless they have been explicitly turned off.  
   PLOTTING COMMANDS: plg, plm, plc, plv, plf, pli, plt, pldj  

             limits  
          or limits, xmin, xmax, ymin, ymax,  
                     square=0/1, nice=0/1, restrict=0/1  
          or old_limits= limits()  
          or limits, old_limits  
 
     In the first form, restores all four plot limits to extreme values.  
     In the second form, sets the plot limits in the current coordinate  
     system to XMIN, XMAX, YMIN, YMAX, which may be nil or omitted to  
     leave the corresponding limit unchanged, a number to fix the  
     corresponding limit to a specified value, or the string "e" to  
     make the corresponding limit take on the extreme value of the  
     currently displayed data.  
     If present, the square keyword determines whether limits marked  
     as extreme values will be adjusted to force the x and y scales  
     to be equal (square=1) or not (square=0, the default).  
     If present, the nice keyword determines whether limits will be  
     adjusted to nice values (nice=1) or not (nice=0, the default).  
     There is a subtlety in the meaning of "extreme value" when one  
     or both of the limits on the OPPOSITE axis have fixed values --  
     does the "extreme value" of the data include points which  
     will not be plotted because their other coordinate lies outside  
     the fixed limit on the opposite axis (restrict=0, the default),  
     or not (restrict=1)?  
     If called as a function, limits returns an array of 5 doubles;  
     OLD_LIMITS(1:4) are the current xmin, xmax, ymin, and ymax,  
     and int(OLD_LIMITS(5)) is a set of flags indicating extreme  
     values and the square, nice, restrict, and log flags.  
     In the fourth form, OLD_LIMITS is as returned by a previous  
     limits call, to restore the limits to a previous state.  
     In an X window, the limits may also be adjusted interactively  
     with the mouse.  Drag left to zoom in and pan (click left to zoom  
     in on a point without moving it), drag middle to pan, and click  
     (and drag) right to zoom out (and pan).  If you click just above  
     or below the plot, these operations will be restricted to the  
     x-axis; if you click just to the left or right, the operations  
     are restricted to the y-axis.  A ctrl-left click, drag, and  
     release will expand the box you dragged over to fill the plot  
     (other popular software zooms with this paradigm).  If the  
     rubber band box is not visible with ctrl-left zooming, try  
     ctrl-middle or ctrl-right for alternate XOR masks.  Such  
     mouse-set limits are equivalent to a limits command specifying  
     all four limits EXCEPT that the unzoom command can revert to  
     the limits before a series of mouse zooms and pans.  
     Holding the shift key and pressing the left mouse button is  
     equivalent to pressing the middle mouse button.  Similarly,  
     pressing meta-left is equivalent to the right button.  This  
     permits access to the middle and right button functions on  
     machines (e.g.- most laptops) with two button or one button  
     mice.  
     The limits you set using the limits or range functions carry over  
     to the next plot -- that is, an fma operation does NOT reset the  
     limits to extreme values.  

             logxy, xflag, yflag  
 
     sets the linear/log axis scaling flags for the current coordinate  
     system.  XFLAG and YFLAG may be nil or omitted to leave the  
     corresponding axis scaling unchanged, 0 to select linear scaling,  
     or 1 to select log scaling.  

             marker=   plotting keyword  
 
     selects the character used for occasional markers along a polyline,  
     or for the polymarker if type is "none".  The special values  
     '\1', '\2', '\3', '\4', and '\5' stand for point, plus, asterisk,  
     circle, and cross, which are prettier than text characters on output  
     to some devices.  The default marker is the next available capital  
     letter, 'A', 'B', ..., 'Z'.  
   PLOTTING COMMANDS: plg, plc  

             marks=   plotting keyword  
 
     selects unadorned lines (marks=0), or lines with occasional markers  
     (marks=1).  Ignored if type is "none" (indicating polymarkers instead  
     of occasional markers).  The spacing and phase of the occasional  
     markers can be altered using the mspace and mphase keywords; the  
     character used to make the mark can be altered using the marker  
     keyword.  
   PLOTTING COMMANDS: plg, plc  

 mcolor  
 

             mesh_loc(y0, x0)  
          or mesh_loc(y0, x0, y, x)  
          or mesh_loc(y0, x0, y, x, ireg)  
 
     returns the zone index (=i+imax*(j-1)) of the zone of the mesh  
     (X,Y) (with optional region number array IREG) containing the  
     point (X0,Y0).  If (X0,Y0) lies outside the mesh, returns 0.  
     Thus, eg- ireg(mesh_loc(x0, y0, y, x, ireg)) is the region number of  
     the region containing (x0,y0).  If no mesh specified, uses default.  
     X0 and Y0 may be arrays as long as they are conformable.  
     For mesh_loc wrappers to duplicate the functionality of the  
     digitize and interp functions in 2D, see the library file digit2.i.  
     After #include "digit2.i", type:  help,digit2  

             result= mouse(system, style, prompt)  
 
     displays a PROMPT, then waits for a mouse button to be pressed,  
     then released.  Returns array of eleven doubles:  
       result= [x_pressed, y_pressed, x_released, y_released,  
                xndc_pressed, yndc_pressed, xndc_released, yndc_released,  
                system, button, modifiers]  
     If SYSTEM>=0, the first four coordinate values will be relative to  
     that coordinate system.  
     For SYSTEM<0, the first four coordinate values will be relative to  
     the coordinate system under the mouse when the button was pressed.  
     The second four coordinates are always normalized device coordinates,  
     which start at (0,0) in the lower left corner of the 8.5x11 sheet of  
     paper the picture will be printed on, with 0.0013 NDC unit being  
     1/72.27 inch (1.0 point).  Look in the style sheet for the location  
     of the viewport in NDC coordinates (see the style keyword).  
     If STYLE is 0, there will be no visual cues that the mouse  
     command has been called; this is intended for a simple click.  
     If STYLE is 1, a rubber band box will be drawn; if STYLE is 2,  
     a rubber band line will be drawn.  These disappear when the  
     button is released.  
     Clicking a second button before releasing the first cancels the  
     mouse function, which will then return nil.  
     Ordinary text input also cancels the mouse function, which again  
     returns nil.  
     The left button reverses forground for background (by XOR) in  
     order to draw the rubber band (if any).  The middle and right  
     buttons use other masks, in case the rubber band is not visible  
     with the left button.  
     long(result(9)) is the coordinate system in which the first four  
     coordinates are to be interpreted.  
     long(result(10)) is the button which was pressed, 1 for left, 2  
     for middle, and 3 for right (4 and 5 are also possible).  
     long(result(11)) is a mask representing the modifier keys which  
     were pressed during the operation: 1 for shift, 2 for shift lock,  
     4 for control, 8 for mod1 (alt or meta), 16 for mod2, 32 for mod3,  
     64 for mod4, and 128 for mod5.  
     Holding the shift key and pressing the left mouse button is  
     equivalent to pressing the middle mouse button.  Similarly,  
     pressing meta-left is equivalent to the right button.  This  
     permits access to the middle and right button functions on  
     machines (e.g.- most laptops) with two button or one button  
     mice.  The long(result(10)) value returned by mouse() reflects  
     this convention, returning 2 or 3 for those cases, even though  
     it is button 1 that is actually being pressed.  Therefore, there  
     is no way to distinguish shift-left from shift-middle, because the  
     long(result(11)) mask indicates tht the shift button is pressed  
     in either case.  (And on a machine without a middle button,  
     there would be no way to emulate shift-middle anyway.)  

             moush()  
          or moush(y, x, ireg)  
 
     returns the 1-origin zone index for the point clicked in  
     for the default mesh, or for the mesh (X,Y) (region array IREG).  

 mphase  
 

 msize  
 

             mspace=   plotting keyword  
          or mphase=   plotting keyword  
          or msize=    plotting keyword  
          or mcolor=   plotting keyword  
 
     selects the spacing, phase, and size of occasional markers placed  
     along polylines.  The msize also selects polymarker size if type  
     is "none".  The spacing and phase are in NDC units (0.0013 NDC  
     equals 1.0 point); the default mspace is 0.16, and the default  
     mphase is 0.14, but mphase is automatically incremented for  
     successive curves on a single plot.  The msize is in relative  
     units, with the default msize of 1.0 representing 10 points.  
     The mcolor keyword is the same as the color keyword, but controls  
     the marker color instead of the line color.  Setting the color  
     automatically sets the mcolor to the same value, so you only  
     need to use mcolor if you want the markers for a curve to be a  
     different color than the curve itself.  
   PLOTTING COMMANDS: plg, plc  

 opaque  
 

 orient  
 

             palette, filename  
          or palette, source_window_number  
          or palette, red, green, blue, ntsc=1/0  
          or palette, red, green, blue, gray  
          or palette, red, green, blue, query=1  
          or palette, red, green, blue, gray, query=1  
 
     sets (or retrieves with query=1) the palette for the current  
     graphics window.  The FILENAME is the name of a Gist palette file;  
     the standard palettes are "earth.gp", "stern.gp", "rainbow.gp",  
     "heat.gp", "gray.gp", and "yarg.gp".  Use the maxcolors keyword  
     in the pldefault command to put an upper limit on the number of  
     colors which will be read from the palette in FILENAME.  
     In the second form, the palette for the current window is copied  
     from the SOURCE_WINDOW_NUMBER.  If the X colormap for the window is  
     private, there will still be two separate X colormaps for the two  
     windows, but they will have the same color values.  
     In the third form, RED, GREEN, and BLUE are 1-D arrays of the same  
     length specifying the palette you wish to install; the values  
     should vary between 0 and 255, and your palette should have no  
     more than 240 colors.  If ntsc=0, monochrome devices (such as most  
     laser printers) will use the average brightness to translate your  
     colors into gray; otherwise, the NTSC (television) averaging will  
     be used (.30*RED+.59*GREEN+.11*BLUE).  Alternatively, you can specify  
     GRAY explicitly.  
     Ordinarily, the palette is not dumped to a hardcopy file  
     (color hardcopy is still rare and expensive), but you can  
     force the palette to dump using the window or hcp_file commands.  
     See the dump= keyword for the hcp_file and window commands if you  
     are having trouble getting color in your hardcopy files.  

             pause, milliseconds  
          or pause(milliseconds)  
 
     pause for the specified number of milliseconds of wall clock  
     time, or until input arrives from the keyboard.  
     If you call pause as a function, the return value is 1  
     if the specified number of milliseconds elapsed, or 0 if  
     keyboard input caused the pause to abort.  
     This is intended for use in creating animated sequences.  

             pdf, name  
 
     writes the picture in the current graphics window to the Adobe PDF  
     file NAME+".pdf" (i.e.- the suffix .pdf is added to NAME).  The  
     pdf file is intended to be imported into MS PowerPoint or other  
     commercial presentation software, or into in pdftex or pdflatex  
     documents; it is cropped.  The result should be equivalent to  
     running the epstopdf utility (which comes with TeX, see www.tug.org)  
     on the eps file produced by the eps command.  
     This function requires ghostscript.  Any hardcopy file associated with  
     the current window is first closed, but the default hardcopy file is  
     unaffected.  As a side effect, legends are turned off and color table  
     dumping is turned on for the current window.  
     The external variable EPSGS_CMD contains the command to start  
     ghostscript.  

             plc, z, y, x, levs=z_values  
          or plc, z, y, x, ireg, levs=z_values  
          or plc, z, levs=z_values  
 
     plots a contours of Z on the mesh Y versus X.  Y, X, and IREG are  
     as for plm.  The Z array must have the same shape as Y and X.  
     The function being contoured takes the value Z at each point  
     (X,Y) -- that is, the Z array is presumed to be point-centered.  
     The Y, X, and IREG arguments may all be omitted to default to the  
     mesh set by the most recent plmesh call.  
     The LEVS keyword is a list of the values of Z at which you want  
     contour curves.  The default is eight contours spanning the  
     range of Z.  
     See plfc if you want to color the regions between contours.  
     The following keywords are legal (each has a separate help entry):  
   KEYWORDS: legend, hide  
             type, width, color, smooth  
             marks, marker, mspace, mphase  
             smooth, triangle, region  

             pldefault, key1=value1, key2=value2, ...  
 
     sets default values for the various properties of graphical elements.  
     The keywords can be most of the keywords that can be passed to the  
     plotting commands:  
       plg:  color, type, width,  
             marks, mcolor, msize, mspace, mphase,  
             rays, rspace, rphase, arrowl, arroww  
       pldj: color, type, width  
       plt:  color, font, height, orient, justify, opaque  
       plm:  color, type, width  
       plv:  color, hollow, width, aspect  
       plc:  color, type, width,  
             marks, mcolor, marker, msize, mspace, mphase  
       plf:  edges, ecolor, ewidth  
     The initial default values are:  
       color="fg", type="solid", width=1.0 (1/2 point),  
       marks=1, mcolor="fg", msize=1.0 (10 points),  
          mspace=0.16, mphase=0.14,  
       rays=0, arrowl=1.0 (10 points), arroww=1.0 (4 points),  
          rspace=0.13, rphase=0.11375,  
       font="helvetica", height=12.0, justify="NN", opaque=0,  
       hollow= 0, aspect=0.125,  
       edges=0, ecolor="fg", ewidth=1.0 (1/2 point)  
     Additional default keywords are:  
       dpi, style, legends  (see window command)  
       palette              (to set default filename as in palette command)  
       maxcolors            (default 200)  

             pldj, x0, y0, x1, y1  
 
     plots disjoint lines from (X0,Y0) to (X1,Y1).  X0, Y0, X1, and Y1  
     may have any dimensionality, but all must have the same number of  
     elements.  
     The following keywords are legal (each has a separate help entry):  
   KEYWORDS: legend, hide  
             type, width, color  

             pleb, y, x, dx=dx, dy=dy  
 
     plots Y vs. X with error bars.  
     Uncertainty on X and/or Y are specified with the dx= and dy= keywords.  
     X and Y must have same dimensions, dx= and dy= must be conformable  
     with X (or Y).  Either dx or dy may be nil for no error bar in that  
     direction.  Scalar dx or dy gives equal error bars at all points,  
     dimsof(dx)==dimsof(X), etc., gives different error bar at each point.  
     dx= and dy= may also have a trailing dimension of length 2 in order  
     to get asymmetric error bars; dx(..,1) is the lower error bar length,  
     and dx(..,2) is the upper error bar length in that case, etc.  
     If marker=, msize=, or width= is specified, markers are positioned  
     at X, Y using plmk.  Use the mfill=1 keyword to get filled markers  
     (width>=10. in plmk; width= refers to error bar width in pleb).  
   EXAMPLE:  
      x = [0, 1, 2, 3];  
      y = [0, 2, 4, 7];  
      pleb, y, x, dx=0.2, dy=[0.3, 0.4, 0.5, 0.3], mfill=1;  
         Uncertainties on dx are the same for all X, and those  
         on Y are different for each value of Y.  Filled markers  
         will be displayed at (X, Y).  
   KEYWORDS: color, width, marker, msize  
      dx     uncertainty on X  
      dy     uncertainty on Y  

             pledit, key1=value1, key2=value2, ...  
          or pledit, n_element, key1=value1, key2=value2, ...  
          or pledit, n_element, n_contour, key1=value1, key2=value2, ...  
 
     changes some property of element number N_ELEMENT (and contour  
     number N_CONTOUR of that element).  If N_ELEMENT and N_CONTOUR are  
     omitted, the default is the most recently added element, or the  
     element specified in the most recent plq query command.  
     The keywords can be any of the keywords that apply to the current  
     element.  These are:  
       plg:  color, type, width,  
             marks, mcolor, marker, msize, mspace, mphase,  
             rays, rspace, rphase, arrowl, arroww,  
             closed, smooth  
       pldj: color, type, width  
       plt:  color, font, height, orient, justify, opaque  
       plm:  region, boundary, inhibit, color, type, width  
       plf:  region  
       plv:  region, color, hollow, width, aspect, scale  
       plc:  region, color, type, width,  
             marks, mcolor, marker, msize, mspace, mphase  
             smooth, levs  
     (For contours, if you aren't talking about a particular N_CONTOUR,  
      any changes will affect ALL the contours.)  
     A plv (vector field) element can also take the scalem  
     keyword to multiply all vector lengths by a specified factor.  
     A plt (text) element can also take the dx and/or dy  
     keywords to adjust the text position by (dx,dy).  

             plf, z, y, x  
          or plf, z, y, x, ireg  
          or plf, z  
 
     plots a filled mesh Y versus X.  Y, X, and IREG are as for plm.  
     The Z array must have the same shape as Y and X, or one smaller  
     in both dimensions.  If Z is of type char, it is used "as is",  
     otherwise it is linearly scaled to fill the current palette, as  
     with the bytscl function.  
     (See the bytscl function for explanation of top, cmin, cmax.)  
     The mesh is drawn with each zone in the color derived from the Z  
     function and the current palette; thus Z is interpreted as a  
     zone-centered array.  
     As for pli and plfp, Z may also be a 3x(NX-1)x(NY-1) array  
     of char giving the [r,g,b] components of each color.  See the  
     color keyword for cautions about using this if you do not have  
     a true color display.  
     The Y, X, and IREG arguments may all be omitted to default to the  
     mesh set by the most recent plmesh call.  
     A solid edge can optionally be drawn around each zone by setting  
     the EDGES keyword non-zero.  ECOLOR and EWIDTH determine the edge  
     color and width.  The mesh is drawn zone by zone in order from  
     IREG(2+imax) to IREG(jmax*imax) (the latter is IREG(imax,jmax)),  
     so you can achieve 3D effects by arranging for this order to  
     coincide with back-to-front order.  If Z is nil, the mesh zones  
     are filled with the background color, which you can use to  
     produce 3D wire frames.  
     The following keywords are legal (each has a separate help entry):  
   KEYWORDS: legend, hide  
             region, top, cmin, cmax, edges, ecolor, ewidth  

             plfc, z, y, x, levs=z_values  
          or plfc, z, y, x, ireg, levs=z_values  
 
     fills contours of Z on the mesh Y versus X.  Y, X, and IREG are  
     as for plm.  The Z array must have the same shape as Y and X.  
     The function being contoured takes the value Z at each point  
     (X,Y) -- that is, the Z array is presumed to be point-centered.  
     The LEVS keyword is a list of the values of Z at which you want  
     contour curves.  These curves divide the mesh into numberof(LEVS)+1  
     regions, each of which is filled with a solid color.  If LEVS is  
     nil, up to 19 "nice" equally spaced level values spanning the  
     range of Z are selected.  The level values actually used are  
     always output to the external variable plfc_levs.  
     If you specify levs=, you may also specify colors= a list of  
     colors of length numberof(LEVS)+1.  The colors should be indices  
     into the current palette.  If you do not specify them, equally  
     spaced colors are chosen.  
     The following keywords are legal (each has a separate help entry):  
   KEYWORDS: triangle, region  

             plfp, z, y, x, n  
 
     plots a list of filled polygons Y versus X, with colors Z.  
     The N array is a 1D list of lengths (number of corners) of the  
     polygons; the 1D colors array Z has the same length as N.  The  
     X and Y arrays have length sum(N).  
     If Z is of type char, it is used "as is", otherwise it is linearly  
     scaled to fill the current palette, as with the bytscl function.  
     If Z is nil, the background color is used for every polygon.  
     (See the bytscl function for explanation of top, cmin, cmax.)  
     As for plf and pli, Z may also be a 3-by-numberof(N) array of  
     char giving the [r,g,b] components of each color.  See the  
     color keyword for cautions about using this if you do not have  
     a true color display.  
     As a special case, if n(2:)==1, the first polygon is assumed  
     to have NDC coordinates, while the remaining individual X and Y  
     values are in world coordinates.  The first polygon is drawn  
     numberof(n)-1 times, with its (0,0) placed at each of the  
     individual (X,Y) values in succession.  This is a hack to enable  
     plotting of more elaborate data markers than plg,type=0 -- see  
     the plmk function for details.  
     The following keywords are legal (each has a separate help entry):  
   KEYWORDS: legend, hide, top, cmin, cmax, edges, ecolor, ewidth  

             plg, y, x  
          or plg, y  
 
     plots a graph of Y versus X.  Y and X must be 1-D arrays of equal  
     length; if X is omitted, it defaults to [1, 2, ..., numberof(Y)].  
     A keyword n=[n1,n2,n3,...nN] can be used to add N curves.  In this  
     case, sum(n) must be numberof(y).  
     The following keywords are legal (each has a separate help entry):  
   KEYWORDS: legend, hide  
             type, width, color, closed, smooth  
             marks, marker, mspace, mphase  
             rays, arrowl, arroww, rspace, rphase  

             pli, z  
          or pli, z, x1, y1  
          or pli, z, x0, y0, x1, y1  
 
     plots the image Z as a cell array -- an array of equal rectangular  
     cells colored according to the 2-D array Z.  The first dimension  
     of Z is plotted along x, the second dimension is along y.  
     If Z is of type char, it is used "as is", otherwise it is linearly  
     scaled to fill the current palette, as with the bytscl function.  
     (See the bytscl function for explanation of top, cmin, cmax.)  
     As for plf and plfp, Z may also be a 3D array with 1st dimension 3  
     of char giving the [r,g,b] components of each color.  See the  
     color keyword for cautions about using this if you do not have  
     a true color display.  
     If X1 and Y1 are given, they represent the coordinates of the  
     upper right corner of the image.  If X0, and Y0 are given, they  
     represent the coordinates of the lower left corner, which is at  
     (0,0) by default.  If only the Z array is given, each cell will be  
     a 1x1 unit square, with the lower left corner of the image at (0,0).  
     The following keywords are legal (each has a separate help entry):  
   KEYWORDS: legend, hide, top, cmin, cmax  

             plm, y, x, boundary=0/1, inhibit=0/1/2  
          or plm, y, x, ireg, boundary=0/1, inhibit=0/1/2  
          or plm, boundary=0/1, inhibit=0/1/2  
 
     plots a mesh of Y versus X.  Y and X must be 2-D arrays with equal  
     dimensions.  If present, IREG must be a 2-D region number array  
     for the mesh, with the same dimensions as X and Y.  The values of  
     IREG should be positive region numbers, and zero for zones which do  
     not exist.  The first row and column of IREG never correspond to any  
     zone, and should always be zero.  The default IREG is 1 everywhere  
     else.  If present, the BOUNDARY keyword determines whether the  
     entire mesh is to be plotted (boundary=0, the default), or just the  
     boundary of the selected region (boundary=1).  If present, the  
     INHIBIT keyword causes the (X(,j),Y(,j)) lines to not be plotted  
     (inhibit=1), or the (X(i,),Y(i,)) lines to not be plotted (inhibit=2).  
     By default (inhibit=0), mesh lines in both logical directions are  
     plotted.  
     The Y, X, and IREG arguments may all be omitted to default to the  
     mesh set by the most recent plmesh call.  
     The following keywords are legal (each has a separate help entry):  
   KEYWORDS: legend, hide  
             type, width, color  
             region  

             plmesh, y, x, ireg, triangle=tri_array  
          or plmesh  
 
     sets the default mesh for subsequent plm, plc, plv, and plf calls.  
     In the second form, deletes the default mesh (until you do this,  
     or switch to a new default mesh, the default mesh arrays persist and  
     take up space in memory).  The Y, X, and IREG arrays should all be  
     the same shape; Y and X will be converted to double, and IREG will  
     be converted to int.  If IREG is omitted, it defaults to IREG(1,)=  
     IREG(,1)= 0, IREG(2:,2:)=1; that is, region number 1 is the whole  
     mesh.  The triangulation array TRI_ARRAY is used by plc; the  
     correspondence between TRI_ARRAY indices and zone indices is the  
     same as for IREG, and its default value is all zero.  
     The IREG or TRI_ARRAY arguments may be supplied without Y and X  
     to change the region numbering or triangulation for a given set of  
     mesh coordinates.  However, a default Y and X must already have been  
     defined if you do this.  
     If Y is supplied, X must be supplied, and vice-versa.  

             plmk, y,x  
 
     Make a scatter plot of the points Y versus X.  If X is nil,  
     it defaults to indgen(numberof(Y)).  By default, the marker  
     cycles through 7 predefined marker shapes.  You may specify a shape  
     using the marker= keyword, line width using the width= keyword (you  
     get solid fills for width>=10), color using the color= keyword.  
     You can also use the msize= keyword to scale the marker (default  
     msize=1.0).  You can change the default width, color, or msize  
     using the plmk_default function.  
     The predefined marker= values are:  
     marker=  
       1        square  
       2        cross  
       3        triangle  
       4        circle  
       5        diamond  
       6        cross (rotated 45 degrees)  
       7        triangle (upside down)  
     You may also put marker=[xm,ym] where xm and ym are vectors  
     of NDC coordinates to design your own custom marker shapes.  

             plmk_default, color=color, msize=msize, width=width  
 
     sets default color, msize, and width values for plmk.  Use  
     width=10 to get solid fills.  With no parameters, plmk_default  
     restores the initial default values.  

             plq  
          or plq, n_element  
          or plq, n_element, n_contour  
          or legend_list= plq()  
          or properties= plq(n_element, n_contour)  
 
     Called as a subroutine, prints the list of legends for the current  
     coordinate system (with an "(H)" to mark hidden elements), or prints  
     a list of current properties of element N_ELEMENT (such as line type,  
     width, font, etc.), or of contour number N_CONTOUR of element number  
     N_ELEMENT (which must be contours generated using the plc command).  
     Called as a function, returns either the list of legend strings, or a  
     list of pointers to the values of the various element properties.  
     Elements and contours are both numbered starting with one; hidden  
     elements or contours are included in this numbering.  
     The PROPERTIES list returned by plq is a list of pointers to the  
     relevent properties for the specified graphical element.  Each  
     possible property has a particular index in the returned PROPERTIES  
     list as follows:  
     *PROPERTIES(1)   int([element type (0 for none, 1 for plg, 2 for pldj,  
                                         3 for plt, 4 for plm, 5 for plf,  
                                         6 for plv, 7 for plc, 8 for pli,  
                                         9 for plfp),  
                           hide flag])  
     *PROPERTIES(2)   string(legend)  
     *PROPERTIES(3)   int array, depends on type (names match keywords):  
       1 plg:  [color, type, marks, mcolor, marker, rays, closed, smooth]  
       2 pldj: [color, type]  
       3 plt:  [color, font, orient, justify, opaque]  
       4 plm:  [color, type, region, boundary, inhibit]  
       5 plf:  [region, edges, ecolor, rgb_flag]  
       6 plv:  [region, color, hollow]  
       7 plc:  [region, color, type, marks, mcolor, marker, smooth]  
       8 pli:  [rgb_flag]  
       9 plfp: [edges, ecolor, rgb_flag]  
     *PROPERTIES(4)   double array, depends on type (names match keywords):  
       1 plg:  [width, msize, mspace, mphase, rspace, rphase, arrowl, arroww]  
       2 pldj: [width]  
       3 plt:  [height, x, y]  
       4 plm:  [width]  
       5 plf:  [ewidth]  
       6 plv:  [width, aspect, scale]  
       7 plc:  [width, msize, mspace, mphase]  
       8 pli:  [x0, y0, x1, y1]  
       9 plfp: [ewidth]  
     *PROPERTIES(5)   long array, depends on type (names match arguments):  
       1 plg:  [npoints, &x, &y]  
       2 pldj: [npoints, &x0, &y0, &x1, &y1]  
       3 plt:  [nchars, &text]  
       4 plm:  [imax, jmax, &x, &y, &ireg]  
       5 plf:  [imax, jmax, &x, &y, &ireg, &colors]  
       6 plv:  [imax, jmax, &x, &y, &ireg, &vx, &vy]  
       7 plc:  [imax, jmax, &x, &y, &ireg, &z, &triangle, nlevs, &levs]  
       8 pli:  [imax, jmax, &colors]  
       9 plfp: [n, &x, &y, &colors, &pn]  
     You can use the reshape function to peek at the data at the addresses  
     returned in PROPERTIES(5) as longs.  The appropriate data types are:  
     char for text, int for ireg, short for triangle, char for colors, and  
     double for everything else.  In a plf, colors is (imax-1)-by-(jmax-1).  
     Although PROPERTIES(5) returns pointers to the data plotted, attempting  
     to poke new values into this data will not produce immediate changes  
     to your plot, since the graphics package does not realize that anything  
     has changed.  Use pledit to make changes to plotted elements.  
     The plq function always operates on the current coordinate system  
     in the current graphics window; use window and plsys to change these.  

             plsys, n  
          or plsys(n)   or   plsys()  
 
     sets the current coordinate system to number N in the current  
     graphics window.  If N equals 0, subsequent elements will be  
     plotted in absolute NDC coordinates outside of any coordinate  
     system.  The default style sheet "work.gs" defines only a single  
     coordinate system, so the only other choice is N equal 1.  You  
     can make up your own style sheet (using a text editor) which  
     defines mulitple coordinate systems.  You need to do this if  
     you want to display four plots side by side on a single page,  
     for example.  The standard style sheets "work2.gs" and "boxed2.gs"  
     define two overlayed coordinate systems with the first labeled  
     to the right of the plot and the second labeled to the left of  
     the plot.  When using overlayed coordinate systems, it is your  
     responsibility to ensure that the x-axis limits in the two  
     systems are identical.  
     Return value is coordinate system setting before this call;  
     input n may be nil to retrieve this without changing it.  Return  
     value can be <0 if the information is unavailable for some reason.  

             plt, text, x, y, tosys=0/1  
 
     plots TEXT (a string) at the point (X,Y).  The exact relationship  
     between the point (X,Y) and the TEXT is determined by the  
     justify keyword.  TEXT may contain newline ("\n") characters  
     to output multiple lines of text with a single call.  The  
     coordinates (X,Y) are NDC coordinates (outside of any coordinate  
     system) unless the tosys keyword is present and non-zero, in  
     which case the TEXT will be placed in the current coordinate  
     system.  However, the character height is NEVER affected by the  
     scale of the coordinate system to which the text belongs.  
     Note that the pledit command takes dx and/or dy keywords to  
     adjust the position of existing text elements.  
     The characters ^, _, and ! are treated specially in TEXT.  
     ^ begins a superscript, _ begins a subscript, and ! causes the  
     following character to be rendered using the symbol font.  As  
     special cases, !^, !_, and !! render the ^, _, and ! characters  
     themselves.  However, if ! is the final character of TEXT  
     (or immediately before a newline in multiline text), it  
     loses its special meaning.  TEXT has just three modes: ordinary,  
     superscript, and subscript.  A ^ character enters superscript  
     mode from ordinary or subscript mode, and returns to ordinary  
     mode from superscript mode.  A _ enters subscript mode, except  
     from subscript mode it returns to ordinary mode.  For example,  
     Euclid said, "!pr^2", and Einstein said, "G_!s!n_=8!pT_!s!n".  
     One final special escape: !] produces the ^ character in the  
     symbol font (it is a perpendicular sign, whereas ] is just ]).  
     The following keywords are legal (each has a separate help entry):  
   KEYWORDS: legend, hide  
             color, font, height, opaque, orient, justify  

             plt1, text, x, y  
 
     same as plt, but TEXT, X, and Y may be arrays to plot multiple  
     strings.  The tosys= keyword works as for plt.  
   KEYWORDS: color, font, height, opaque, orient, justify  

             pltitle, title  
 
     Plot TITLE centered above the coordinate system for any of the  
     standard Gist styles.  You may want to customize this for other  
     plot styles.  

             plv, vy, vx, y, x, scale=dt  
          or plv, vy, vx, y, x, ireg, scale=dt  
          or plv, vy, vx, scale=dt  
 
     plots a vector field (VX,VY) on the mesh (X,Y).  Y, X, and IREG are  
     as for plm.  The VY and VX arrays must have the same shape as Y and X.  
     The Y, X, and IREG arguments may all be omitted to default to the  
     mesh set by the most recent plmesh call.  
     The SCALE keyword is the conversion factor from the units of  
     (VX,VY) to the units of (X,Y) -- a time interval if (VX,VY) is a velocity  
     and (X,Y) is a position -- which determines the length of the  
     vector "darts" plotted at the (X,Y) points.  If omitted, SCALE is  
     chosen so that the longest ray arrows have a length comparable  
     to a "typical" zone size.  
     You can use the scalem keyword in pledit to make adjustments to the  
     SCALE factor computed by default.  
     The following keywords are legal (each has a separate help entry):  
   KEYWORDS: legend, hide  
             type, width, color, smooth  
             marks, marker, mspace, mphase  
             triangle, region  

             png, name  
 
     writes the picture in the current graphics window to the PNG  
     file NAME+".png" (i.e.- the suffix .png is added to NAME).  The  
     png file is intended to be imported into MS PowerPoint or other  
     commercial presentation software.  This function starts ghostscript  
     using the EPSGS_CMD variable.  With the gray=1 keyword, you get  
     the pnggray ghostscript device, otherwise png16m.  
     The default yorick graphics window is 6 inches square, and by  
     default png produces 72 dpi (dot per inch) output.  You can change  
     this with the dpi= keyword; dpi=300 is extremely high resolution.  

             range, ymin, ymax  
 
     sets the y-axis plot limits in the current coordinate system to  
     YMIN, YMAX, which may be nil or omitted to leave the corresponding  
     limit unchanged, a number to fix the corresponding limit to a  
     specified value, or the string "e" to make the corresponding limit  
     take on the extreme value of the currently displayed data.  
     Use    limits, xmin, xmin  
     to accomplish the same function for the x-axis plot limits.  

             raw_style: get_style, set_style, read_style, write_style  
             #include "style.i"  
 
     alternatives to the style= keyword of the window command which  
     allow the interpreter to set or get all the details of the  
     window style.  Include "style.i" and read the help for get_style.  

             rays=   plotting keyword  
 
     selects unadorned lines (rays=0), or lines with occasional ray  
     arrows (rays=1).  Ignored if type is "none".  The spacing and phase  
     of the occasional arrows can be altered using the rspace and rphase  
     keywords; the shape of the arrowhead can be modified using the  
     arroww and arrowl keywords.  
   PLOTTING COMMANDS: plg, plc  

             redraw  
 
     redraws the X window associated with the current graphics window.  

             region=   plotting keyword  
 
     selects the part of mesh to consider.  The region should match one  
     of the numbers in the IREG array.  Putting region=0 (the default)  
     means to plot the entire mesh, that is, everything EXCEPT region  
     zero (non-existent zones).  Any other number means to plot only  
     the specified region number; region=3 would plot region 3 only.  
   PLOTTING COMMANDS: plm, plc, plv, plf  

             rgb = rgb_read()  
          or rgb = rgb_read(n)  
 
     Read contents of current graphics window, or of graphics window N.  
     RGB is a 3xNXxNY array of char where NXxNY is the current shape of  
     the window in pixels.  RGB(1,,) is the red component, RGB(2,,) is  
     the green component, and RGB(3,,) is the blue component, with 0  
     black and 255 full intensity.  RGB(,,1) is the top row of the  
     window, RGB(,,2) the second row, and so on to RGB(,,0), which is  
     the bottom row.  (So RGB(,,::-1) to pli redraws a copy.)  

 rphase  
 

             rspace=   plotting keyword  
          or rphase=   plotting keyword  
          or arroww=   plotting keyword  
          or arrowl=   plotting keyword  
 
     selects the spacing, phase, and size of occasional ray arrows  
     placed along polylines.  The spacing and phase are in NDC units  
     (0.0013 NDC equals 1.0 point); the default rspace is 0.13, and  
     the default rphase is 0.11375, but rphase is automatically  
     incremented for successive curves on a single plot.  
     The arrowhead width, arroww, and arrowhead length, arrowl are  
     in relative units, defaulting to 1.0, which translates to an  
     arrowhead 10 points long and 4 points in half-width.  
   PLOTTING COMMANDS: plg  

 smooth  
 

             spann(zmin, zmax, n)  
 
     return no more than N equally spaced "nice" numbers between  
     ZMIN and ZMAX.  

             triangle=   plotting keyword  
 
     sets the triangulation array for a contour plot.  The triangulation  
     array must be the same shape as the IREG (region number) array, and  
     the correspondence between mesh zones and indices is the same as  
     for IREG.  The triangulation array is used to resolve the ambiguity  
     in saddle zones, in which the function Z being contoured has two  
     diagonally opposite corners high, and the other two corners low.  
     The triangulation array element for a zone is 0 if the algorithm is  
     to choose a triangulation, based on the curvature of the first  
     contour to enter the zone.  If zone (i,j) is to be triangulated  
     from point (i-1,j-1) to point (i,j), then TRIANGLE(i,j)=1,  
     while if it is to be triangulated from (i-1,j) to (i,j-1), then  
     TRIANGLE(i,j)=-1.  Contours will never cross this "triangulation  
     line".  
     You should rarely need to fiddle with the traingulation array;  
     it is a hedge for dealing with pathological cases.  
   PLOTTING COMMANDS: plc  

             type=   plotting keyword  
 
     selects line type.  Valid values are the strings "solid", "dash",  
     "dot", "dashdot", "dashdotdot", and "none".  The "none" value  
     causes the line to be plotted as a polymarker.  You should also  
     check the plmk function if you need polymarkers.  
     The type value may also be a number; 0 is "none", 1 is "solid",  
     2 is "dash", 3 is "dot", 4 is "dashdot", and 5 is "dashdotdot".  
   PLOTTING COMMANDS: plg, plm, plc, pldj  

             unzoom  
 
     restores limits to their values before zoom and pan operations  
     performed interactively using the mouse.  
     Use    old_limits=  limits()  
            ...  
            limits, old_limits  
     to save and restore plot limits generally.  

             port= viewport();  
 
     returns [xmin,xmax,ymin,ymax] of the current viewport (or 0,0,0,0  
     if currently plotting to system 0) in NDC coordinates.  

             width=   plotting keyword  
 
     selects line width.  Valid values are positive floating point numbers  
     giving the line thickness relative to the default line width of one  
     half point, width= 1.0.  
   PLOTTING COMMANDS: plg, plm, plc, pldj, plv (only if hollow=1)  

             window, n, display="host:server.screen", dpi=100/75, wait=0/1,  
                        private=0/1, hcp="hcp_filename", dump=0/1,  
                        legends=1/0, style="style_sheet_filename",  
                        width=wpixels,height=hpixels,rgb=1,  
                        parent=id,xpos=x_in_parent,ypos=y_in_parent  
 
     select window N as the current graphics output window.  N may  
     range from 0 to 63, inclusive.  Each graphics window corresponds to  
     an X window, and optionally has its own associated hardcopy file.  
     If N is omitted, it defaults to the current coordinate system.  
     The X window will appear on your default display at 75 dpi, unless  
     you specify the display and/or dpi keywords.  A dpi=100 X window  
     is larger than a dpi=75 X window; both represent the same thing  
     on paper.  Use display="" to create a graphics window which has  
     no associated X window (you should do this if you want to make  
     plots in a non-interactive batch mode).  
     By default, if the X window needs to be created, the graphics area  
     will be 450x450 pixels if dpi=75, or 600x600 pixels if dpi=100,  
     representing a 6x6 inch square on hardcopy paper.  You can override  
     this default initial size using the width and height keywords.  
     These settings remain in force indefinitely; use width=0,height=0  
     to return to the default dpi-dependent behavior.  For a dpi=75,  
     landscape=0 window, width=638,height=825 displays the entire sheet  
     of hardcopy paper.  Supplying these keywords will not change the  
     size of an existing window; only newly created windows.  
     By default, an X window will attempt to use shared colors, which  
     permits several Yorick graphics windows (including windows from  
     multiple instances of Yorick) to use a common palette.  You can  
     force an X window to post its own colormap (set its colormap  
     attribute) with the private=1 keyword.  You will most likely have  
     to fiddle with your window manager to understand how it handles  
     colormap focus if you do this.  Use private=0 to return to shared  
     colors.  
     By default, Yorick will not wait for the X window to become visible;  
     code which creates a new window, then plots a series of frames to  
     that window should use wait=1 to assure that all frames are actually  
     plotted.  
     By default, a graphics window does NOT have a hardcopy file  
     of its own -- any request for hardcopy are directed to the  
     default hardcopy file, so hardcopy output from any window goes  
     to a single file.  By specifying the hcp keyword, however, a  
     hardcopy file unique to this window will be created.  If the  
     "hcp_filename" ends in ".cgm", the hardcopy file is a binary CGM  
     file; otherwise, hardcopy files are in Postscript format.  Use  
     hcp="" to revert to the default hardcopy file (closing the window  
     specific file, if any).  The legends keyword, if present, controls  
     whether the curve legends are (legends=1, the default) or are not  
     (legends=0) dumped to the hardcopy file.  The dump keyword, if  
     present, controls whether all colors are converted to a gray scale,  
     (dump=0), or the current palette is dumped at the beginning of each  
     page of hardcopy output (dump=1, the default).  (The legends keyword  
     applies to all pictures dumped to hardcopy from this graphics  
     window.  The dump keyword applies only to the specific hardcopy  
     file defined using the hcp keyword -- use the dump keyword in the  
     hcp_file command to get the same effect in the default hardcopy  
     file.)  
     Use rgb=1 to set the rgb color model when you are creating a  
     window on an 8-bit display on which you intend to use three  
     component rgb colors (see color).  This installs the 5x9x5  
     colorcube and avoids having to issue the palette command  
     after the first true color object has been drawn.  
     If both display="" and hcp="", the graphics window will be  
     entirely eliminated.  
     The style keyword, if present, specifies the name of a Gist style  
     sheet file; the default is "work.gs".  The style sheet determines  
     the number and location of coordinate systems, tick and label styles,  
     and the like.  Other choices include "axes.gs", "boxed.gs",  
     "work2.gs", and "boxed2.gs".  
     The parent=id keyword can be used to make the yorick window a  
     subwindow of an existing window.  The id is an integer, which is  
     the system-dependent window id that must be retrieved from the  
     application which owns the parent window.  When parent= is defined,  
     xpos= and ypos= specify the offset in that window; both default to 0.  
     If invoked as a function, window(...) returns the current  
     window number.  

             winkill  
          or winkill, n  
 
     deletes the current graphics window, or graphics window N (0-63).  

             xytitles, xtitle, ytitle  
 
       -or- xytitles, xtitle, ytitle, [deltax,deltay]  
     Plot XTITLE horizontally under the viewport and YTITLE vertically  
     to the left of the viewport.  If the tick numbers interfere with  
     the labels, you can specify the [DELTAX,DELTAY] in NDC units to  
     displace the labels.  (Especially for the y title, the adjustment  
     may depend on how many digits the numbers on your scale actually  
     have.)  Note that DELTAX moves YTITLE and DELTAY moves XTITLE.  
     WARNING: There is no easy way to ensure that this type of title  
              will not interfere with the tick numbering.  Interference  
              may make the numbers or the title or both illegible.  

             zoom_factor, factor  
 
     sets the zoom factor for mouse-click zoom in and zoom out operations.  
     The default FACTOR is 1.5; FACTOR should always be greater than 1.0.