i/rezone

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    /*
       REZONE.I
       Point and click rezoner, written in interpreted Yorick.

       $Id$
     */
    /*    Copyright (c) 1994.  The Regents of the University of California.
                        All rights reserved.  */

    require, "button.i";
    require, "bowtie.i";

    func toy_mesh (filename)
    /* DOCUMENT toy_mesh, filename
         generates a toy mesh in the file FILENAME in order to be able to

         play with the rezone function.  (FILENAME must be a string enclosed
         in double quotes, of course.)
       SEE ALSO: rezone
     */
    {
      rt= span(1., 0., 6)(,-:1:11);
      zt= span(0., 2., 11)(-:1:6,);
      rt(3,3)+= 0.15;
      zt(3,3)+= 0.15;
      rt(3,7)+= 0.05;
      zt(3,7)+= 0.25;

      save, createb(filename), rt, zt;
    }

    extern rez_load_hook ;
    /* DOCUMENT rez_load_hook
         If non-nil, filename to be included immediately after rez.i.
         This file can be used to set personalized default values for the
         many parameters.
         Some parameters may be set before loading rez.i, as well

       SEE ALSO: rez_kstyle, rez_lstyle
     */

    extern rez_kstyle ;

    extern rez_lstyle ;

    extern rez_color ;

    /* DOCUMENT rez_kstyle, rez_lstyle, rez_color

         is a vector of three longs:  [type,width,color]
         type MUST be 1, 2, 3, 4, or 5,

         width MUST be 1, 2, 3, 4, 5, 6, 7, or 8,

         and color MUST be -1, -2, -3, -4, -5, -6, -7, -8, -9, or -10

         Either or both parameters may be set before or after including
         rez.i; by default:

           rez_kstyle= [4, 1, -2]    (dashdot, thin, foreground color)

           rez_lstyle= [1, 1, -2]    (solid, thin, foreground color)

         To distinguish K and L by color instead of type, try:

           rez_kstyle= [1, 1, -7]    (dashdot, thin, blue)

           rez_lstyle= [1, 1, -5]    (solid, thin, red)

         If the variable rez_color is true (non-nil and non-zero) when
         this file is included, then these will be the default.

       SEE ALSO: rez_load_hook
     */
    /* This choice distinguishes by line type.  */
    _old_rez_color= rez_color;

    if (is_void(rez_kstyle)) rez_kstyle= rez_color? [1, 1, -7]:[4, 1, -2];

    if (is_void(rez_lstyle)) rez_lstyle= rez_color? [1, 1, -5]:[1, 1, -2];

    extern rez_mark ;
    /* DOCUMENT rez_mark

         Causes rezone functions to mark bowtied or chevroned (boomeranged)
         zones when the mesh is plotted.  MUST have one of the following values:
           0 to not mark bowtied or chevroned zones

           1 to put a B at the center of the positive triangle of bowtied zones
           2 to put a C at the center of the larger wing of chevroned zones
           3 to mark both bowtied and chevroned zones

         By default, rez_mark is 3; you may set it to a different value
         either before or after including rez.i.

       SEE ALSO: rez_mesh, rez_next, rez_prev, rez_drag
     */

    if (is_void(rez_mark)) rez_mark= 3;

    _rez_on_black= 0;

    extern rez_palette ;
    /* DOCUMENT rez_palette

         3-by-ncolors array used as a palette when rez_regs region coloring

         is set.  The index in rez_regs is the second index into rez_palette.
         The length 3 first index is [r,g,b].
         The default is 15 pastels.
       SEE ALSO: rez_regs
     */

    rez_palette= [[255,230,230],[230,255,230],[230,230,255],[242,242,230],
    	      [230,242,242],[242,230,242],[236,249,230],[236,236,242],
    	      [249,236,230],[230,236,249],[242,236,236],[230,249,236],
    	      [249,230,236],[236,242,236],[236,230,249]];
    _old_rez_palette= [];

    func rez_chk_palette
    {

      if (typeof(rez_palette)!=typeof(_old_rez_palette) ||

          dimsof(rez_palette)(1)!=dimsof(_old_rez_palette)(1) ||

          anyof(dimsof(rez_palette)!=dimsof(_old_rez_palette)) ||

          anyof(rez_palette!=_old_rez_palette)) {

        if (dimsof(rez_palette)(2)!=3)

          error, "rez_palette must be [[r1,g1,b1],[r2,g2,b2],...]";

        if (!is_array(rez_palette) || typeof(rez_palette)=="struct_instance" ||

    	typeof(rez_palette)=="string" || typeof(rez_palette)=="complex" ||

    	min(rez_palette)<0 || max(rez_palette)>255)

          error, "rez_palette values should be between 0 and 255";

        palette, rez_palette(1,), rez_palette(2,), rez_palette(3,);

        _old_rez_palette= rez_palette;
        fma;
      }
    }

    extern rez_regs ;
    /* DOCUMENT rez_regs

         is a vector of region numbers which are to be drawn in the colors
         specified in rez_palette.  Thus:
            rez_regs= [3,5]
         causes regions 3 and 5 to be drawn in colors.  All other regions have
         white backgrounds.  Hilighting too many regions in this way may slow
         down the redraws unacceptably.  To highlight all regions, use:

            rez_regs= indgen(max(rez_ireg))
         This won't work on monochrome monitors, of course.
         The default is rez_regs=[].
       SEE ALSO: rez_palette
     */

    extern rez_adjust_mesh ;

    /* DOCUMENT rez_adjust_mesh
         is an optional hook function which is called after any change to the
         mesh (e.g.- by dragging points) has been made.  If it is defined, it
         may modify the external variables rez_rt and rez_zt.  This hook can
         be used, for example, to force points along some k or l line to lie
         along a symmetry line.

       SEE ALSO: rezone, rez_all, rez_mesh
     */

    func rez_plm (flag, adj_check)
    {

      if (adj_check && is_func(rez_adjust_mesh)) rez_adjust_mesh;

      fma;

      extern rez_kstyle, rez_lstyle;

      if (rez_color!=_old_rez_color) {

        rez_kstyle= rez_color? [1, 1, -7]:[4, 1, -2];

        rez_lstyle= rez_color? [1, 1, -5]:[1, 1, -2];
        _old_rez_color= rez_color;
      }

      if (!is_void(rez_regs)) {
        rez_chk_palette;

        n= numberof(rez_regs);

        colors= array(char, dimsof(rez_rt)(2), dimsof(rez_rt)(3));
        for (i=1 ; i<=n ; i++) {
          reg= rez_regs(i);

          if (noneof(rez_ireg==reg) || reg<=0) continue;

          colors(where(rez_ireg==reg))= i-1;

          plf, colors, rez_rt, rez_zt, rez_ireg, legend=string(0), region=reg;
        }
      } else if (_rez_on_black) {
        rez_ptexist;
        list= where(rez_ptx);
        r= rez_rt(list);
        z= rez_zt(list);

        pli, [['\0']], min(z), min(r), max(z), max(r);
      }

      plm, rez_rt, rez_zt, rez_ireg, legend=string(0), inhibit=1,

           color= rez_kstyle(3), width= rez_kstyle(2), type= rez_kstyle(1);

      plm, rez_rt, rez_zt, rez_ireg, legend=string(0), inhibit=2,

           color= rez_lstyle(3), width= rez_lstyle(2), type= rez_lstyle(1);

      if (rez_mark&3) {
        extern rez_map;
        local rr, zz;
        if (flag || is_void(flag)) {
          if (_rez_polar) {
    	zt= rez_zt*cos(rez_rt);
    	rt= rez_zt*sin(rez_rt);
          } else {
    	zt= rez_zt;
    	rt= rez_rt;
          }

          rez_map= bowtie(rt,zt,rez_ireg);
        }
        for (i=1 ; i<=2 ; i++) {

          if (!(rez_mark&i)) continue;

          rez_getrz, where(rez_map==(i-1));
          if (!is_void(rr)) {
    	a1= (rr(2,2,)-rr(2,1,))*(zz(2,1,)-zz(1,1,)) -
    	  (zz(2,2,)-zz(2,1,))*(rr(2,1,)-rr(1,1,));
    	a2= (rr(1,1,)-rr(1,2,))*(zz(1,2,)-zz(2,2,)) -
    	  (zz(1,1,)-zz(1,2,))*(rr(1,2,)-rr(2,2,));
    	a3= (rr(2,1,)-rr(1,1,))*(zz(1,1,)-zz(1,2,)) -
    	  (zz(2,1,)-zz(1,1,))*(rr(1,1,)-rr(1,2,));
    	if (i==1) {
    	  /* this is a magic trick for bowtied zones */
    	  index= ((a3>=0.) | (a1>=0.)<<1 | (a2>=0.)<<2) - 1;
    	  p1= [1,0,3,2](index);
    	  p2= [3,1,2,0](index);
    	  p3= [2,3,0,1](index);
    	  p4= [0,2,1,3](index);

    	  index= indgen(1:numberof(rr):4);
    	  p1+= index;
    	  p2+= index;
    	  p3+= index;
    	  p4+= index;
    	  /* now p1 p2 p3 p4 are the indices of the points in (rr,zz)
    	     with p1 p2 being the positive edge of the bowtied zone,
    	     so that p1 p3 and p2 p4 cross */
    	  r1= rr(p1);
    	  z1= zz(p1);
    	  r2= rr(p2);
    	  z2= zz(p2);
    	  r3= rr(p3);
    	  z3= zz(p3);
    	  r4= rr(p4);
    	  z4= zz(p4);
    	  fa= (r3-r2)*(z4-z1);
    	  fb= -(r4-r1)*(z3-z2);
    	  det= fa+fb;
    	  fa/= det;
    	  fb/= det;
    	  rr= r1*fa + r2*fb + (r3-r2)*(r4-r1)*(z2-z1)/det;
    	  zz= z2*fa + z1*fb - (z3-z2)*(z4-z1)*(r2-r1)/det;
    	  rr= (rr+r1+r2)/3.0;
    	  zz= (zz+z1+z2)/3.0;
    	  marker= 'B';
    	  legend= "B: bowtied zones";
    	} else {
    	  a4= (rr(1,2,)-rr(2,2,))*(zz(2,2,)-zz(2,1,)) -
    	    (zz(1,2,)-zz(2,2,))*(rr(2,2,)-rr(2,1,));
    	  r1= (rr(1,1,)+rr(2,1,)+rr(2,2,))/3.0;
    	  z1= (zz(1,1,)+zz(2,1,)+zz(2,2,))/3.0;
    	  r2= (rr(1,1,)+rr(2,2,)+rr(1,2,))/3.0;
    	  z2= (zz(1,1,)+zz(2,2,)+zz(1,2,))/3.0;
    	  r3= (rr(2,1,)+rr(1,1,)+rr(1,2,))/3.0;
    	  z3= (zz(2,1,)+zz(1,1,)+zz(1,2,))/3.0;
    	  r4= (rr(1,2,)+rr(2,2,)+rr(2,1,))/3.0;
    	  z4= (zz(1,2,)+zz(2,2,)+zz(2,1,))/3.0;
    	  mask= (a1>0. & a2>0.);
    	  which= [a1*mask,a2*mask,a3*(1-mask),a4*(1-mask)](,mxx);
    	  n= numberof(a1);
    	  list= indgen(n)+n*(which-1);
    	  rr= [r1,r2,r3,r4](list);
    	  zz= [z1,z2,z3,z4](list);
    	  marker= 'C';
    	  legend= "C: chevroned zones";
    	}

    	plg,rr,zz,type=0,marker=marker,legend=legend;
          }
        }
      }
    }

    _rez_polar= 0n;

    func rez_toggle
    {
      zt= rez_zt;
      rt= rez_rt;
      _rez_polar= !_rez_polar;
      if (_rez_polar) {
        rez_zt= abs(rt,zt);
        rez_rt= atan(rt,zt+1.e-99);
      } else {
        rez_zt= zt*cos(rt);
        rez_rt= zt*sin(rt);
      }
    }

    /* These four parameters specify the viewport position, which is actually
       a function of the stylesheet being used, and potentially changes as

       a function of window or coordinate system within the window.  The numbers
       here should work decently for the work.gs and boxed.gs styles.  If you
       set them very large, the only side effect is that clicking way outside

       the coordinate system (e.g.- missing the Done or Undo button) will pick
       up the nearest mesh vertex).  This is not that unreasonable a behavior,
       especially since any miscue can be undone.  See rez_load_hook.  */
    _rez_xvp=  (0.615+0.175)*0.5;
    _rez_dxvp= (0.615-0.175)*0.5;
    _rez_yvp=  (0.895+0.455)*0.5;
    _rez_dyvp= (0.895-0.455)*0.5;

    /* Following setup could be placed in rez_load_hook to allow any style:
      _rez_xvp=  0.5;
      _rez_dxvp= 0.6;
      _rez_yvp=  0.5;
      _rez_dyvp= 0.6;
     */

    func rezone (filename, all=, quiet=)
    /* DOCUMENT rezone, filename
           -or- rezone

         Invoke the mouse-driven rezoner.  Input is taken from variables
         rt, zt, and ireg in the file FILENAME (which is prompted for if
         omitted).  Output is written to a different file as rt, zt, and
         ireg.  The output file also contains copies rez_rt, rez_zt, and
         rez_ireg in case the mesh under a different name is desirable,
         as well as rez_rt0, rez_zt0, and rez_ireg0, which are the original
         mesh.

         If you click on [Escape], you may continue rezoning where you left

         off by typing   rezone   with no arguments.

         When you are finished, click [OK] to write the output file.

         Use [Zoom or Pan] and [Set Styles] to change the plot limits or
         line colors and styles.  The [Zoom or Pan] screen has buttons which
         "warp" you to each bowtied or chevroned "problem" zone, as well as
         a button to toggle between rectangular and polar coordinates.

         Click [Drag Points] to drag points one at a time with the mouse.

         Click [Adjust Line] to smooth the points on logical line segments.
         You first click on the endpoints P and Q, then click a button to

         smooth or equal space the poionts between P and Q, or drag any
         point between P and Q to establish equal ratio zones ("ER" operation).

         Click [Adjust Region] to smooth the points in logically rectangular
         regions.  You first click on the opposite corners P and R of the

         rectangle PQRS, then click a button to smooth the interior points,

         or click on a point on one of the four edges to transfer the spacing

         on that edge throughout the region PQRS ("EQ" operation).

         The [Undo] (or [Redo]) button removes the effect of the most

         recent drag points, adjust line, or adjust region operation.

         Hints:
         (0) After [Escape], the current mesh is in the variables
             rez_zt, rez_rt, and rez_ireg.  You can change these

    	 variables "by hand" before restarting rezone to make
    	 algebraic adjustments.
         (1) Switch to polar coordinates during an [Adjust Line] or
             [Adjust Region] in order to get points to lie along a
    	 circular arc.  If your center point is not (0,0), you
    	 will need to [Escape] and subtract your center point
    	 from the rez_zt and rez_rt variables yourself, then

    	 [Escape] a second time to restore the proper coordinates
    	 before you write the output file.

         (2) You can select a center point as the second point during
             [Adjust Line] or [Adjust Region].  When you do this, the

    	 K (or L) value of this second point will be the same as
    	 that of the first point -- otherwise there is no way to
    	 distinguish among all of the logical points at the center.
    	 In an [Adjust Region], the center point will be labeled
    	 Q instead of R as usual, and you will need to choose a
    	 third point (S) to complete the rectangle PQRS.

         (3) If you set the variable rez_color=1 before you include
             rezone.i, you will get K lines and L lines drawn in different
    	 colors instead of the default (which is K lines dashdot and
    	 L lines solid).

         (4) If you have a color monitor, you can set rez_regs before

             invoking rezone in order to highlight a list of regions.

         The ALL keyword will be passed to the nbow function, which will
         not be called if the QUIET keyword is non-nil and non-zero.  By
         default, a short summary of bowtied and chevroned zones is printed.

         If you need help on how to use one of the screens, try getting

         help on the appropriate on of these see-also topics, e.g.-

            help, rez_style

         to get help on the [Set Styles] screen.

       SEE ALSO: rez_all, rez_drag, rez_ladj, rez_radj, rez_zoom, rez_style,

                 rez_color, rez_regs, rez_adjust_mesh, toy_mesh
     */
    {
      extern rez_name;
      if (is_void(filename)) {
        if (is_void(rez_name)) {
          filename= "";

          read, format="%s", prompt="Name of Z-file: ", filename;
        }
      }
      if (!is_void(filename)) {
        /* begin a new rezone */
        for (i=1 ; i<=2 ; i++) {

          if (!is_void(open(filename,"rb",1))) break;

          write, "Cannot open "+filename;

          read, format="%s", prompt="Name of Z-file: ", filename;
        }
        if (i>2) {
          write, "Quitting rezone";
          return;
        }

        rez_mesh, openb(filename), quiet=quiet, all=all;

        if (!is_void(rez_zt) && !is_void(rez_rt)) rez_name= filename;

        write, "For help, click [Escape], then type:    help, rezone";
      }

      esca= rez_all();
      if (_rez_polar) rez_toggle;
      if (esca) return;

      default= rez_name+"_rez";
      for (i=1 ; i<=3 ; i++) {
        line=

          rdline(prompt="Output filename (default "+default+", ? to escape): ");
        line= strtok(line)(1);
        if (!line) line= default;
        else if (line=="?") line= string(0);
        if (line!=rez_name) break;
      }
      if (!line || line==rez_name) {

        write, "Escaping from rezone -- to resume, type    rezone";
        return;
      }

      zt= rez_zt;
      rt= rez_rt;
      ireg= rez_ireg;
      at_pdb_close|= 1;

      save, createb(line), zt, rt, ireg, rez_zt, rez_rt, rez_ireg,
        rez_zt0, rez_rt0, rez_ireg0;

      rez_name= [];
    }

    func rez_all (dummy)
    /* DOCUMENT rez_all

         Click on [Drag Points] to drag points around with the mouse with
         rez_drag.

         Click on [Adjust Line] to adjust points along a line segment with
         rez_ladj.

         Click on [Adjust Region] to adjust points in a rectangular region
         with rez_radj.

         Click on the [Undo] button to undo the previous change.
         Click on the [Redo] button to redo the previous undo.
         Click on the [Revert] to return to the original mesh.

         When you are finished moving points around, click on [OK].

         Click on [Escape] to exit with a non-zero return value.

         Click on [Zoom or Pan] to change the plot limits (see rez_zoom).

         Click on [Set Styles] to change the line styles or colors (see
         rez_style).

       SEE ALSO: rez_ladj, rez_mesh, rez_zoom, rez_style, rez_adjust_mesh
     */
    {

      done= Button(text="OK",x=.203,y=.895,dx=.020,dy=.012);

      undo= Button(text="Undo",x=.254,y=.895,dx=.025,dy=.012);

      esca= Button(text="Escape",x=.344,y=.895,dx=.035,dy=.012);

      zorp= Button(text="Zoom or Pan",x=.464,y=.895,dx=.054,dy=.012);

      sets= Button(text="Set Styles",x=.569,y=.895,dx=.045,dy=.012);

      drag= Button(text="Drag Points",x=.240,y=.375,dx=.054,dy=.012);

      ladj= Button(text="Adjust Line",x=.350,y=.375,dx=.050,dy=.012);

      radj= Button(text="Adjust Region",x=.468,y=.375,dx=.062,dy=.012);

      reve= Button(text="Revert",x=.577,y=.375,dx=.030,dy=.012);

      rez_plm, 1;

      button_plot, done, undo, esca, zorp, sets, drag, ladj, radj, reve;

      zt= zt2= rez_zt;
      rt= rt2= rez_rt;

      for (;;) {
        m= mouse(1, 2, "");

        if (is_void(m)) { rdline,prompt=""; continue; }
        x= m(5);
        y= m(6);

        if (button_test(done,x,y)) break;

        if (button_test(esca,x,y)) {

          write, "Escaping from rezone -- to resume, type    rezone";
          rez_plm,1;
          return 1;
        }

        if (button_test(undo,x,y)) {
          if (undo.text=="Undo") {
    	rez_zt= zt;
    	rez_rt= rt;
    	undo.text= "Redo";
          } else {
    	rez_zt= zt2;
    	rez_rt= rt2;
    	undo.text= "Undo";
          }
          rez_plm, 1;

        } else if (button_test(reve,x,y)) {
          zt= rez_zt;
          rt= rez_rt;
          undo.text= "Undo";
          rez_zt= zt2= rez_zt0;
          rez_rt= rt2= rez_rt0;
          rez_plm, 1;

        } else if (button_test(zorp,x,y)) {
          rez_zoom;
          rez_plm, 0;

        } else if (button_test(sets,x,y)) {
          rez_style;
          rez_plm, 0;

        } else if (button_test(drag,x,y)) {
          zt= rez_zt;
          rt= rez_rt;
          undo.text= "Undo";
          rez_drag;
          zt2= rez_zt;
          rt2= rez_rt;

        } else if (button_test(ladj,x,y)) {
          zt= rez_zt;
          rt= rez_rt;
          undo.text= "Undo";
          rez_ladj;
          zt2= rez_zt;
          rt2= rez_rt;

        } else if (button_test(radj,x,y)) {
          zt= rez_zt;
          rt= rez_rt;
          undo.text= "Undo";
          rez_radj;
          zt2= rez_zt;
          rt2= rez_rt;
        } else {
          rez_ding;
          continue;
        }

        button_plot, done, undo, esca, zorp, sets, drag, ladj, radj, reve;
      }

      rez_plm, 1;
      return 0;
    }

    func rez_drag
    /* DOCUMENT rez_drag

         Allow points in the rezone mesh to be dragged around with

         the mouse.  Press mouse button near a vertex, move mouse
         to desired position of that vertex, and release button.

         If the point where you click is less than twice the distance to the

         second closest point than to the nearest point, the point will not
         be moved (you will hear a beep when you release the button).
         Click on the [Undo] button to undo the previous move; you can undo
         up to 100 previous moves by successive [Undo] clicks.

         When you are finished moving points around, click on [OK].

         Click on [Zoom or Pan] to change the plot limits (see rez_zoom).

         Click on [Set Styles] to change the line styles or colors (see
         rez_style).

       SEE ALSO: rez_ladj, rez_radj, rez_mesh, rez_zoom, rez_style
     */
    {

      done= Button(text="OK",x=.203,y=.895,dx=.020,dy=.012);

      undo= Button(text="Undo",x=.254,y=.895,dx=.025,dy=.012);

      lab1= Button(text="Drag points.",x=.344,y=.895,dx=.050,dy=.012,width=-1);

      zorp= Button(text="Zoom or Pan",x=.464,y=.895,dx=.054,dy=.012);

      sets= Button(text="Set Styles",x=.569,y=.895,dx=.045,dy=.012);

      rez_plm, 1;

      button_plot, done, undo, lab1, zorp, sets;

      list= array(0.0, 3, 100);  /* keep last 100 moves for undo */

      kmax= dimsof(rez_rt)(2);
      for (;;) {
        m= mouse(1, 2, "");

        if (is_void(m)) { rdline,prompt=""; continue; }
        flag= j= 0;

        if (button_test(done,m(5),m(6))) break;

        if (button_test(undo,m(5),m(6))) {
          j= long(list(1,1));
          zt= list(2,1);
          rt= list(3,1);
          list(,1:-1)= list(,2:0);
          list(,0)= 0.0;
          flag= 1;

        } else if (button_test(zorp,m(5),m(6))) {
          rez_zoom;
          flag= j= 2;

        } else if (button_test(sets,m(5),m(6))) {
          rez_style;
          flag= j= 2;

        } else if (abs(_rez_xvp-m(5))<=_rez_dxvp ||

    	       abs(_rez_yvp-m(6))<=_rez_dyvp) {
          j= rez_find(m(1), m(2));

          if (numberof(_rez_center)) j= 0;
          zt= m(3);
          rt= m(4);
        }
        if (j<1) {
          rez_ding;
        } else {
          if (flag<2) {
    	if (!flag) {
    	  list(,2:0)= list(,1:-1);
    	  list(1,1)= j;
    	  list(2,1)= rez_zt(j);
    	  list(3,1)= rez_rt(j);
    	}
    	rez_zt(j)= zt;
    	rez_rt(j)= rt;
          }
          rez_plm, (flag<2), 1;

          button_plot, done, undo, lab1, zorp, sets;
          if (!flag) {

    	text= swrite(format="moved (%ld,%ld)",(j-1)%kmax+1,(j-1)/kmax+1);
    	plt, text, 0.35, 0.375;
          }
        }
      }

      rez_plm, 1;
    }

    func rez_ladj
    /* DOCUMENT rez_ladj
         Adjust the points along a logical line segment PQ:

         Click on [Set P] or [Set Q] to set the endpoints of the segment.
         When P and Q have been set, click [OK]; this button will

         read [Cancel] if P and Q do not have either the same K or the
         same L index.

         Click on [Smooth] to smooth the points along PQ.

         Click on [Equal Space] to make the points along PQ equally spaced.
         This forces PQ to be a straight line.

         Drag any point between P and Q to get equal ratio spacing of all
         the points between P and Q.  This also forces PQ to be a straight
         line; if PQ is initially curved, you may want to click on
         [Equal Space] before you attempt to drag points.

         Click on the [Undo] button to undo the previous adjustment; you can
         undo up to 20 previous adjustments by successive [Undo] clicks.

         When you are finished adjusting lines, click on [OK].

         Click on [Zoom or Pan] to change the plot limits (see rez_zoom).

         Click on [Set Styles] to change the line styles or colors (see
         rez_style).

         Hint:

             You can select a center point as the second point during

             rez_ladj.  When you do this, the K (or L) value of this second
    	 point will be the same as that of the first point --
    	 otherwise there is no way to distinguish among all of the
    	 logical points at the center.

       SEE ALSO: rez_drag, rez_radj, rez_mesh, rez_zoom, rez_style
     */
    {

      done= Button(text="OK",x=.203,y=.895,dx=.020,dy=.012);

      undo= Button(text="Undo",x=.254,y=.895,dx=.025,dy=.012);

      lab1= Button(text="Adjust line.",x=.344,y=.895,dx=.050,dy=.012,width=-1);

      zorp= Button(text="Zoom or Pan",x=.464,y=.895,dx=.054,dy=.012);

      sets= Button(text="Set Styles",x=.569,y=.895,dx=.045,dy=.012);

      setp= Button(text="Set P",x=.208,y=.375,dx=.027,dy=.012);

      setq= Button(text="Set Q",x=.268,y=.375,dx=.027,dy=.012);

      drag= Button(text="Drag for ER",x=.355,y=.375,
    	       dx=.035,dy=.012,width=-1);

      smth= Button(text="Smooth",x=.454,y=.375,dx=.035,dy=.012);

      eqsp= Button(text="Equal Space",x=.550,y=.375,dx=.054,dy=.012);

      mode= 1;
      jP= jQ= oldjP= oldjQ= 0;
      rez_plm, 1;
      kmax= dimsof(rez_rt)(2);
      lab1.text= "Select P.";
      setp.text= "Set Q";
      done.text= "Cancel";
      done.dx= 0.033;

      button_plot, done, lab1, zorp, sets, setp;

      for (;;) {
        m= mouse(1, 2, "");

        if (is_void(m)) { rdline,prompt=""; continue; }
        x= m(5);
        y= m(6);

        if (button_test(zorp,x,y)) {
          rez_zoom;

        } else if (button_test(sets,x,y)) {
          rez_style;

        } else if (button_test(setp,x,y)) {
          mode= 1 + (setp.text!="Set P");
          if (mode==1) {
    	lab1.text= "Select P.";
    	setp.text= "Set Q";
          } else {
    	lab1.text= "Select Q.";
    	setp.text= "Set P";
          }

        } else if (mode) {

          if (button_test(done,x,y)) {
    	if (done.text=="Cancel") {
    	  if (!oldjP || !oldjQ) break;
    	  jP= oldjP;
    	  jQ= oldjQ;
    	} else {
    	  if (kP==kQ) {
    	    k= kP;

    	    l= rez_range(min(lP,lQ):max(lP,lQ));
    	  } else {
    	    l= lP;

    	    k= rez_range(min(kP,kQ):max(kP,kQ));
    	  }
    	  zt= rez_zt(k,l);
    	  rt= rez_rt(k,l);

    	  list= array([zt,rt], 20);  /* keep last 20 for undo */
    	}
    	lab1.text= "Adjust line.";
    	setp.text= "Set P";
    	mode= 0;

          } else if (abs(_rez_xvp-x)<=_rez_dxvp ||
    	       abs(_rez_yvp-y)<=_rez_dyvp) {
    	j= rez_find(m(1), m(2));

    	if (numberof(_rez_center)>1) {

    	  kc= (_rez_center-1)%kmax + 1;

    	  lc= (_rez_center-1)/kmax + 1;
    	  if (noneof(kc-kc(1))) kc= kc(1);

    	  else if (noneof(lc-lc(1))) lc= lc(1);
    	  if (mode==1 && jQ>0) {
    	    kd= (jQ-1)%kmax + 1;
    	    ld= (jQ-1)/kmax + 1;

    	    if (numberof(kc)==1 && kc!=kd && anyof(lc==ld))
    	      j= kc + (ld-1)*kmax;

    	    else if (numberof(lc)==1 && lc!=ld && anyof(kc==kd))
    	      j= kd + (lc-1)*kmax;
    	  } else if (mode!=1 && jP>0) {
    	    kd= (jP-1)%kmax + 1;
    	    ld= (jP-1)/kmax + 1;

    	    if (numberof(kc)==1 && kc!=kd && anyof(lc==ld))
    	      j= kc + (ld-1)*kmax;

    	    else if (numberof(lc)==1 && lc!=ld && anyof(kc==kd))
    	      j= kd + (lc-1)*kmax;
    	  }
    	}
    	if (j<1) {
    	  rez_ding;
    	  continue;
    	} else {
    	  if (mode==1) jP= j;
    	  else jQ= j;
    	  kP= (jP-1)%kmax + 1;
    	  lP= (jP-1)/kmax + 1;
    	  kQ= (jQ-1)%kmax + 1;
    	  lQ= (jQ-1)/kmax + 1;
    	}
          } else {
    	rez_ding;
    	continue;
          }

        } else {

          if (button_test(done,x,y)) break;

          if (button_test(undo,x,y)) {
    	rez_zt(k,l)= list(,1,1);
    	rez_rt(k,l)= list(,2,1);
    	list(,,1:-1)= list(,,2:0);

          } else if (button_test(setq,x,y)) {
    	oldjP= jP;
    	oldjQ= jQ;
    	lab1.text= "Select Q.";
    	mode= 2;

          } else if (button_test(smth,x,y)) {
    	zt= rez_zt(k,l);
    	if (numberof(zt)>2) {
    	  rt= rez_rt(k,l);
    	  list(,,2:0)= list(,,1:-1);
    	  list(,1,1)= zt;
    	  list(,2,1)= rt;
    	  zt(2:-1)= zt(zcen)(zcen);
    	  rt(2:-1)= rt(zcen)(zcen);
    	  rez_zt(k,l)= zt;
    	  rez_rt(k,l)= rt;
    	}

          } else if (button_test(eqsp,x,y)) {
    	zt= rez_zt(k,l);
    	n= numberof(zt);
    	if (n>2) {
    	  rt= rez_rt(k,l);
    	  list(,,2:0)= list(,,1:-1);
    	  list(,1,1)= zt;
    	  list(,2,1)= rt;
    	  rez_zt(k,l)= span(zt(1), zt(0), n);
    	  rez_rt(k,l)= span(rt(1), rt(0), n);
    	}

          } else if (abs(_rez_xvp-x)<=_rez_dxvp ||
    	       abs(_rez_yvp-y)<=_rez_dyvp) {
    	j= rez_find(m(1), m(2));

    	if (j<=min(jP,jQ) || j>=max(jP,jQ) ||
    	    (kP==kQ && abs(j-jP)%kmax)) {
    	  rez_ding;
    	  continue;
    	} else {
    	  zP= rez_zt(jP);
    	  rP= rez_rt(jP);
    	  zQ= rez_zt(jQ);
    	  rQ= rez_rt(jQ);
    	  zx= m(3)-zP;
    	  rx= m(4)-rP;
    	  za= zQ-zP;
    	  ra= rQ-rP;
    	  /* set sx to projection of new point onto PQ, normalized to
    	     lie between 0 (at P) and 1 (at Q) */

    	  sx= (za*zx+ra*rx)/abs(za,ra,1.e-35)^2;
    	  if (sx>0. && sx<1.) {
    	    zt= rez_zt(k,l);
    	    rt= rez_rt(k,l);
    	    list(,,2:0)= list(,,1:-1);
    	    list(,1,1)= zt;
    	    list(,2,1)= rt;

    	    n= numberof(zt)-1;  /* already guaranteed >1 */

    	    if (kP==kQ) m= abs((j-1)/kmax + 1 - lP);
    	    else m= abs((j-1)%kmax + 1 - kP);
    	    m= 1./m;

    	    r= rez_solve(1./sx, n*m)^m;
    	    sa= spanl(1., r^(n-1), n)(cum);
    	    sx= [0.0, sa(0)];
    	    zt= interp([zP,zQ], sx, sa);
    	    rt= interp([rP,rQ], sx, sa);
    	    if (kP>kQ || lP>lQ) {
    	      zt= zt(0:1:-1);
    	      rt= rt(0:1:-1);
    	    }
    	    rez_zt(k,l)= zt;
    	    rez_rt(k,l)= rt;
    	  } else {
    	    rez_ding;
    	    continue;
    	  }
    	}
          } else {
    	rez_ding;
    	continue;
          }
        }
        rez_plm, !mode, 1;
        if (!mode || (jP && jQ && ((kQ==kP) ~ (lQ==lP)))) {
          done.text= "OK";
          done.dx= 0.020;
        } else {
          done.text= "Cancel";
          done.dx= 0.033;
        }

        button_plot, done, lab1, zorp, sets, setp;

        if (jP) plg, rez_rt(kP,lP), rez_zt(kP,lP),

          marker='P', type=0, legend=string(0);

        if (jQ) plg, rez_rt(kQ,lQ), rez_zt(kQ,lQ),

          marker='Q', type=0, legend=string(0);

        if (!mode) button_plot, undo, setq, drag, smth, eqsp;
        else if (jP || jQ) {

          text= jP? swrite(format="P=(%ld,%ld)",kP,lP) : "";

          if (jQ) text+= swrite(format="    Q=(%ld,%ld)",kQ,lQ);
          plt, text, 0.35, 0.375;
        }
      }

      rez_plm, 1;
    }

    func rez_radj
    /* DOCUMENT rez_radj
         Adjust the points in a logical rectangle PQRS:

         Click on [Set P] or [Set R] to set the endpoints of the segment.
         When P and R have been set, click [OK]; this button will

         read [Cancel] if P and R have the same K or the same L index.

         Click on a point on any edge of PQRS (but not one of the corners)
         to copy the spacings on that edge throughout the entire region.

         All of the lines of the same type (K-line or L-line) as the edge
         you clicked on will become straight lines.

         Click on [Smooth] to smooth the points interior to PQRS.

         Click on [Smooth 4] to perform the smooth operation four times.

         Click on the [Undo] button to undo the previous adjustment; you can
         undo up to 10 previous adjustments by successive [Undo] clicks.

         When you are finished adjusting regions, click on [OK].

         Click on [Zoom or Pan] to change the plot limits (see rez_zoom).

         Click on [Set Styles] to change the line styles or colors (see
         rez_style).

         Hint:

             You can select a center point as the second point during

             rez_radj.  When you do this, the K (or L) value of this second
    	 point will be the same as that of the first point --
    	 otherwise there is no way to distinguish among all of the
    	 logical points at the center.  The center point will be labeled
    	 Q instead of R as usual, and you will need to choose a third
    	 point (S) to complete the rectangle PQRS.

       SEE ALSO: rez_drag, rez_ladj, rez_mesh, rez_zoom, rez_style
     */
    {

      done= Button(text="OK",x=.203,y=.895,dx=.020,dy=.012);

      undo= Button(text="Undo",x=.254,y=.895,dx=.025,dy=.012);

      lab1= Button(text="Adjust region.",x=.344,y=.895,dx=.050,dy=.012,width=-1);

      zorp= Button(text="Zoom or Pan",x=.464,y=.895,dx=.054,dy=.012);

      sets= Button(text="Set Styles",x=.569,y=.895,dx=.045,dy=.012);

      setp= Button(text="Set P",x=.208,y=.375,dx=.027,dy=.012);

      setr= Button(text="Set R",x=.268,y=.375,dx=.027,dy=.012);

      drag= Button(text="Click edge for EQ",x=.371,y=.375,
    	       dx=.035,dy=.012,width=-1);

      smth= Button(text="Smooth",x=.480,y=.375,dx=.035,dy=.012);

      eqsp= Button(text="Smooth 4",x=.563,y=.375,dx=.041,dy=.012);

      mode= 1;
      jP= jR= jQ= oldjP= oldjR= 0;
      rez_plm, 1;
      kmax= dimsof(rez_rt)(2);
      lab1.text= "Select P.";
      setp.text= "Set R";
      done.text= "Cancel";
      done.dx= 0.033;

      button_plot, done, lab1, zorp, sets, setp;

      for (;;) {
        m= mouse(1, 2, "");

        if (is_void(m)) { rdline,prompt=""; continue; }
        x= m(5);
        y= m(6);

        if (button_test(zorp,x,y)) {
          rez_zoom;

        } else if (button_test(sets,x,y)) {
          rez_style;

        } else if (button_test(setp,x,y)) {
          mode= 1 + (setp.text!="Set P");
          if (mode==1) {
    	lab1.text= "Select P.";
    	setp.text= "Set R";
          } else {
    	lab1.text= "Select R.";
    	setp.text= "Set P";
          }
          jQ= 0;

        } else if (mode) {

          if (button_test(done,x,y)) {
    	if (done.text=="Cancel") {
    	  if (!oldjP || !oldjR) break;
    	  jP= oldjP;
    	  jR= oldjR;
    	} else {
    	  k0= min(kP,kR);
    	  k1= max(kP,kR);
    	  l0= min(lP,lR);
    	  l1= max(lP,lR);
    	  zt= rez_zt(k0:k1,l0:l1);
    	  rt= rez_rt(k0:k1,l0:l1);

    	  list= array([zt,rt], 10);  /* keep last 10 for undo */
    	}
    	lab1.text= "Adjust region.";
    	setp.text= "Set P";
    	mode= jQ= 0;

          } else if (abs(_rez_xvp-x)<=_rez_dxvp ||
    		 abs(_rez_yvp-y)<=_rez_dyvp) {
    	j= rez_find(m(1), m(2));
    	mold= mode;

    	if (numberof(_rez_center)>1) {
    	  if (mode==2 && jP>0) {

    	    kc= (_rez_center-1)%kmax + 1;

    	    lc= (_rez_center-1)/kmax + 1;
    	    if (noneof(kc-kc(1))) kc= kc(1);

    	    else if (noneof(lc-lc(1))) lc= lc(1);
    	    kd= (jP-1)%kmax + 1;
    	    ld= (jP-1)/kmax + 1;

    	    if (numberof(kc)==1 && kc!=kd && anyof(lc==ld))
    	      j= kc + (ld-1)*kmax;

    	    else if (numberof(lc)==1 && lc!=ld && anyof(kc==kd))
    	      j= kd + (lc-1)*kmax;
    	    lab1.text= "Select S.";
    	    mode= 3;
    	  } else {
    	    j= 0;
    	  }
    	}
    	if (j<1) {
    	  rez_ding;
    	  continue;
    	} else {
    	  if (mode==1) jP= j;
    	  else if (mode==2) jR= j;
    	  else if (mode!=mold) jQ= j;
    	  else if (kP==kQ) jR= (j-1)%kmax + 1 + (lQ-1)*kmax;
    	  else jR= kQ + ((j-1)/kmax)*kmax;
    	  kP= (jP-1)%kmax + 1;
    	  lP= (jP-1)/kmax + 1;
    	  kR= (jR-1)%kmax + 1;
    	  lR= (jR-1)/kmax + 1;
    	  kQ= (jQ-1)%kmax + 1;
    	  lQ= (jQ-1)/kmax + 1;
    	}
          } else {
    	rez_ding;
    	continue;
          }

        } else {

          if (button_test(done,x,y)) break;

          if (button_test(undo,x,y)) {
    	rez_zt(k0:k1,l0:l1)= list(,,1,1);
    	rez_rt(k0:k1,l0:l1)= list(,,2,1);
    	list(,,,1:-1)= list(,,,2:0);

          } else if (button_test(setr,x,y)) {
    	oldjP= jP;
    	oldjR= jR;
    	lab1.text= "Select R.";
    	mode= 2;

          } else if (button_test(smth,x,y)) {
    	zt= rez_zt(k0:k1,l0:l1);

    	if (dimsof(zt)(2)>2 && dimsof(zt)(3)>2) {
    	  rt= rez_rt(k0:k1,l0:l1);
    	  list(,,,2:0)= list(,,,1:-1);
    	  list(,,1,1)= zt;
    	  list(,,2,1)= rt;
    	  zt(2:-1,2:-1)= zt(zcen,zcen)(zcen,zcen);
    	  rt(2:-1,2:-1)= rt(zcen,zcen)(zcen,zcen);
    	  rez_zt(k0:k1,l0:l1)= zt;
    	  rez_rt(k0:k1,l0:l1)= rt;
    	}

          } else if (button_test(eqsp,x,y)) {
    	zt= rez_zt(k0:k1,l0:l1);

    	if (dimsof(zt)(2)>2 && dimsof(zt)(3)>2) {
    	  rt= rez_rt(k0:k1,l0:l1);
    	  list(,,,2:0)= list(,,,1:-1);
    	  list(,,1,1)= zt;
    	  list(,,2,1)= rt;
    	  for (ii=0 ; ii<4 ; ii++) {
    	    zt(2:-1,2:-1)= zt(zcen,zcen)(zcen,zcen);
    	    rt(2:-1,2:-1)= rt(zcen,zcen)(zcen,zcen);
    	  }
    	  rez_zt(k0:k1,l0:l1)= zt;
    	  rez_rt(k0:k1,l0:l1)= rt;
    	}

          } else if (abs(_rez_xvp-x)<=_rez_dxvp ||
    		 abs(_rez_yvp-y)<=_rez_dyvp) {
    	j= rez_find(m(1), m(2));
    	kj= (j-1)%kmax + 1;
    	lj= (j-1)/kmax + 1;
    	inl= (lj>l0 && lj<l1);
    	ink= (kj>k0 && kj<k1);
    	zt= rez_zt(k0:k1,l0:l1);
    	rt= rez_rt(k0:k1,l0:l1);
    	if (j>0 && (kj==k0 || kj==k1) && inl) {
    	  list(,,,2:0)= list(,,,1:-1);
    	  list(,,1,1)= zt;
    	  list(,,2,1)= rt;

    	  ds= abs(zt(kj==k0,dif),rt(kj==k0,dif))(-,cum);
    	  ds/= ds(1,0);
    	  rez_zt(k0:k1,l0:l1)= zt(,1) + (zt(,0)-zt(,1))*ds
    	  rez_rt(k0:k1,l0:l1)= rt(,1) + (rt(,0)-rt(,1))*ds
    	} else if (j>0 && (lj==l0 || lj==l1) && ink) {
    	  list(,,,2:0)= list(,,,1:-1);
    	  list(,,1,1)= zt;
    	  list(,,2,1)= rt;

    	  ds= abs(zt(dif,lj==l0),rt(dif,lj==l0))(cum);
    	  ds/= ds(0);
    	  rez_zt(k0:k1,l0:l1)= zt(1,-,) + (zt(0,-,)-zt(1,-,))*ds
    	  rez_rt(k0:k1,l0:l1)= rt(1,-,) + (rt(0,-,)-rt(1,-,))*ds
    	} else {
    	  rez_ding;
    	  continue;
    	}
          } else {
    	rez_ding;
    	continue;
          }
        }
        rez_plm, !mode, 1;
        if (!mode || (jP && jR && kR!=kP && lR!=lP)) {
          done.text= "OK";
          done.dx= 0.020;
        } else {
          done.text= "Cancel";
          done.dx= 0.033;
        }

        button_plot, done, lab1, zorp, sets, setp;

        if (jP) plg, rez_rt(kP,lP), rez_zt(kP,lP),

          marker='P', type=0, legend=string(0);

        if (jR) plg, rez_rt(kR,lR), rez_zt(kR,lR),

          marker='R', type=0, legend=string(0);

        if (jQ) plg, rez_rt(kQ,lQ), rez_zt(kQ,lQ),

          marker='Q', type=0, legend=string(0);
        if (done.text=="OK") {

          if (!jQ) plg, rez_rt(kP,lR), rez_zt(kP,lR),

                     marker='Q', type=0, legend=string(0);

          plg, rez_rt(kR,lP), rez_zt(kR,lP),

            marker='S', type=0, legend=string(0);
        }

        if (!mode) button_plot, undo, setr, drag, smth, eqsp;
        else if (jP || jR) {

          text= jP? swrite(format="P=(%ld,%ld)",kP,lP) : "";

          if (jR) text+= swrite(format="    R=(%ld,%ld)",kR,lR);

          else if (jQ) text+= swrite(format="    Q=(%ld,%ld)",kQ,lQ);
          plt, text, 0.35, 0.375;
        }
      }

      rez_plm, 1;
    }

    _rez_zoom= 0n;

    func rez_zoom
    /* DOCUMENT rez_zoom

         Change limits after setting rez_mesh.

         There are two modes of operation:
         (1) P-mode:
             Click on a point to magnify or demagnify about that point.
    	 Drag the point to move it to a different position in the
    	 viewport.  The left button zooms in (magnifies by 1.5), the
    	 right button zooms out (demagnifies by 1.5), and the middle
    	 button pans (no magnification change).  If you click just

    	 below or just above the tick marks, only the x coordinate
    	 is changed; clicking just to the left or just to the right

    	 of the viewport changes only the y coordinate.
         (2) R-mode:

             Left drag out a rectangle to set the limits to that rectangle.

    	 Right drag out a rectangle to cram the entire current viewport
    	 into that rectangle (an analog to zooming out).
    	 Middle drag to pan as in P-mode (the rubber band rectangle is
    	 meaningless in this case).

          Click the [R-mode] (or [P-mode]) button to change modes.

          Click the [OK] button when you are satisfied with the limits.

          Click the [Undo] button to remove the effect of the previous
          zoom-click.  Up to 100 successive undo operations are allowed.

          Click the [Polar] button to toggle polar coordinates.  The
          vertical axis will be theta, and the horizontal axis radius.
          The polar coordinate origin will be at (zt,rt) = (0,0).

          Click the [Next], [Prev], or [First] buttons to focus in on
          zones which are bowtied or chevroned.  These zones are marked

          by a B or a C, respectively (if rez_mark is set).

       SEE ALSO: rez_mesh
     */
    {

      done= Button(text="OK",x=.203,y=.895,dx=.020,dy=.012);

      undo= Button(text="Undo",x=.254,y=.895,dx=.025,dy=.012);

      lab2= Button(text="Left=in  Middle=pan  Right=out",

    	       x=.413,y=.895,dx=.128,dy=.012,width=-1);

      mode= Button(text=(_rez_zoom?"P-Mode":"R-Mode"),
    	       x=.584,y=.895,dx=.037,dy=.012);

      full= Button(text="Full Mesh",x=.230,y=.375,dx=.046,dy=.012);

      polar= Button(text="Polar",x=.307,y=.375,dx=.025,dy=.012);

      lab3= Button(text="Go To Bowtie:",

    	       x=.402,y=.375,dx=.040,dy=.012,width=-1);

      next= Button(text="Next",x=.486,y=.375,dx=.025,dy=.012);

      prev= Button(text="Prev",x=.536,y=.375,dx=.025,dy=.012);

      first= Button(text="First",x=.587,y=.375,dx=.026,dy=.012);

      rez_plm, 1;

      button_plot, done, undo, lab2, mode, full, polar, lab3, next, prev, first;

      list= array(0.0, 5, 100);  /* keep last 100 limits for undo */
      len= 0;
      for (;;) {
        m= mouse(1, _rez_zoom, "");

        if (is_void(m)) { rdline,prompt=""; continue; }
        x= m(5);
        y= m(6);

        if (button_test(done,x,y)) break;

        if (button_test(undo,x,y)) {
          if (len) {
    	limits, list(,1);
    	list(,1:-1)= list(,2:0);
    	len--;
          } else {
    	rez_ding;
    	continue;
          }

        } else if (button_test(mode,x,y)) {
          _rez_zoom= !_rez_zoom;
          mode.text= (_rez_zoom?"P-Mode":"R-Mode");

        } else if (button_test(full,x,y)) {

          limits;  redraw;
          continue;

        } else if (button_test(polar,x,y)) {
          rez_toggle;
          limits;

        } else if (button_test(next,x,y)) {

          rez_next;  redraw;
          continue;

        } else if (button_test(prev,x,y)) {

          rez_prev;  redraw;
          continue;

        } else if (button_test(first,x,y)) {

          rez_next, 1;  redraw;
          continue;

        } else if (abs(_rez_xvp-x)<=_rez_dxvp ||
    	       abs(_rez_yvp-y)<=_rez_dyvp) {
          x= m(1);
          y= m(2);
          x1= m(3);
          y1= m(4);
          button= long(m(10));
          lims= limits();
          if (!_rez_zoom || button==2) {  /* point mode */
    	if (button==1) f= 1.5;
    	else if (button==2) f= 1.0;
    	else f= 1.0/1.5;
    	x0= x - (x1-lims(1))/f;
    	x1= x - (x1-lims(2))/f;
    	y0= y - (y1-lims(3))/f;
    	y1= y - (y1-lims(4))/f;
    	if (x!=lims(1) && x!=lims(2)) {

    	  if (y!=lims(3) && y!=lims(4)) limits, x0,x1,y0,y1;
    	  else limits, x0,x1;
    	} else {

    	  if (y!=lims(3) && y!=lims(4)) limits, ,,y0,y1;
    	  else limits, x0,x1,y0,y1;
    	}
    	list(,2:0)= list(,1:-1);
    	list(,1)= lims;
    	len++;
          } else if (x!=x1 && y!=y1) {  /* rectangle mode */
    	x0= min(x,x1);
    	x1= max(x,x1);
    	y0= min(y,y1);
    	y1= max(y,y1);
    	if (button!=1) {
    	  f= (lims(2)-lims(1))/(x1-x0);
    	  x0= lims(1) - f*(x0-lims(1));
    	  x1= lims(2) + f*(lims(2)-x1);
    	  f= (lims(4)-lims(3))/(y1-y0);
    	  y0= lims(3) - f*(y0-lims(3));
    	  y1= lims(4) + f*(lims(4)-y1);
    	}
    	limits, x0,x1,y0,y1;
    	list(,2:0)= list(,1:-1);
    	list(,1)= lims;
    	len++;
          } else {
    	rez_ding;
    	continue;
          }
        }
        rez_plm, 0;

        button_plot, done, undo, lab2, mode, full, polar, lab3, next, prev, first;
      }
    }

    func rez_style
    {

      done= Button(text="OK",x=.203,y=.895,dx=.020,dy=.012);

      klin= Button(text="K-line",x=.290,y=.895,dx=.038,dy=.012,width=6.);

      llin= Button(text="L-line",x=.366,y=.895,dx=.038,dy=.012);

      type= Button(text="Type",x=.476,y=.895,dx=.025,dy=.012,width=6.);

      wdth= Button(text="Width",x=.530,y=.895,dx=.029,dy=.012);

      colr= Button(text="Color",x=.586,y=.895,dx=.027,dy=.012);

      bar1= ["1", "2", "3", "4", "5", "6", "7", "8"];
      bar2= ["bg", "fg", "blk", "wht",
    	 "red", "grn", "blu", "cyn", "mag", "yel"];

      bar= array(Button, 10);
      bar.dx= bardx= .022;
      bar.x= barx= .644;
      bar.dy= bardy= .012;

      bar.y= .895-(indgen(10)-1)*2.*bardy;
      bary= avg(bar.y);

      bar(1:5).text= bar1(1:5);
      barn= 5;

      bar(rez_kstyle(1)).width= 6.;
      change= 1;

      for (;;) {
        if (change) {
          i= where(bar.width)(1);
          if (type.width) {

    	if (klin.width) rez_kstyle(1)= i;
    	else rez_lstyle(1)= i;
          } else if (wdth.width) {

    	if (klin.width) rez_kstyle(2)= i;
    	else rez_lstyle(2)= i;
          } else if (colr.width) {

    	if (klin.width) rez_kstyle(3)= -i;
    	else rez_lstyle(3)= -i;
          }
          rez_plm, 0;

          button_plot, done, klin, llin, type, wdth, colr, bar(1:barn);
          change= 0;
        }
        m= mouse(0, _rez_zoom, "");

        if (is_void(m)) { rdline,prompt=""; continue; }
        x= m(5);
        y= m(6);

        if (button_test(done,x,y)) break;

        if (button_test(klin,x,y)) {
          if (klin.width) continue;
          klin.width= 6.;
          llin.width= 0.;
          bar.width= 0.;

          if (type.width) bar(rez_kstyle(1)).width= 6.;

          else if (wdth.width) bar(rez_kstyle(2)).width= 6.;

          else if (colr.width) bar(-rez_kstyle(3)).width= 6.;

        } else if (button_test(llin,x,y)) {
          if (llin.width) continue;
          llin.width= 6.;
          klin.width= 0.;
          bar.width= 0.;

          if (type.width) bar(rez_lstyle(1)).width= 6.;

          else if (wdth.width) bar(rez_lstyle(2)).width= 6.;

          else if (colr.width) bar(-rez_lstyle(3)).width= 6.;

        } else if (button_test(type,x,y)) {
          if (type.width) continue;
          type.width= 6.;
          wdth.width= colr.width= 0.;
          bar(1:5).text= bar1(1:5);
          barn= 5;
          bar.width= 0.;

          if (klin.width) bar(rez_kstyle(1)).width= 6.;

          else bar(rez_lstyle(1)).width= 6.;

        } else if (button_test(wdth,x,y)) {
          if (wdth.width) continue;
          wdth.width= 6.;
          type.width= colr.width= 0.;
          bar(1:8).text= bar1;
          barn= 8;
          bar.width= 0.;

          if (klin.width) bar(rez_kstyle(2)).width= 6.;

          else bar(rez_lstyle(2)).width= 6.;

        } else if (button_test(colr,x,y)) {
          if (colr.width) continue;
          colr.width= 6.;
          type.width= wdth.width= 0.;
          bar.text= bar2;
          barn= 10;
          bar.width= 0.;

          if (klin.width) bar(-rez_kstyle(3)).width= 6.;

          else bar(-rez_lstyle(3)).width= 6.;

        } else if (abs(barx-x)<bardx && abs(bary-y)<2.*barn*bardy) {
          i= long((bar(1).y+bardy - y)/(2.0*bardy)) + 1;
          if (i>0 && i<=barn) {
    	bar.width= 0.;
    	bar(i).width= 6.;
          } else {
    	rez_ding;
    	continue;
          }
        } else {
          rez_ding;
          continue;
        }
        change= 1;
      }
    }

    extern rez_qrt , rez_qzt, rez_qireg;

    /* DOCUMENT rez_qrt, rez_qzt, rez_qireg

         are the names of the mesh variables for rez_mesh, "rt", "zt", and
         "ireg" by default.  Note that ireg is optional.
     */
    rez_qzt= "zt";
    rez_qrt= "rt";
    rez_qireg= "ireg";

    func rez_mesh (rt, zt, ireg, all=, quiet=)

    /* DOCUMENT rez_mesh, rt, zt, ireg
           -or- rez_mesh, rt, zt
           -or- rez_mesh, zfile
         set mesh for rez_... commands.  If ZFILE is specified, it must be a
         binary file containing variables RT, ZT, and (optionally) IREG.

       SEE ALSO: rez_all, rez_adjust_mesh
     */
    {
      extern rez_rt0, rez_zt0, rez_ireg0, rez_rt, rez_zt, rez_ireg;
      extern rez_mapi;

      if (is_stream(rt)) {
        f= rt;
        vars= get_vars(f);

        ireg= rez_getvar(f,vars, rez_qireg);

        zt= rez_getvar(f,vars, rez_qzt);

        rt= rez_getvar(f,vars, rez_qrt);
      }
      if (is_void(ireg)) {

        ireg= array(1, dimsof(rt));
        ireg(1,)= 0;
        ireg(,1)= 0;
      }

      rez_rt0= rez_rt= rt;
      rez_zt0= rez_zt= zt;
      rez_ireg0= rez_ireg= ireg;

      if (is_void(zt) || is_void(rt)) return;
      rez_ptexist;

      rez_mapi= 0;

      if (!quiet) nbow, rez_rt, rez_zt, rez_ireg, all=all;

      rez_plm, 1;
    }

    func rez_next (which)
    /* DOCUMENT rez_next

         zoom in on next bowtied (or chevroned) zone (after rez_mesh).

         With numeric argument, zooms to that bowtie (or chevron).  With

         numeric argument 0, zooms to current bowtie (or chevron).

       SEE ALSO: rez_prev, rez_mark, rez_drag
     */
    {
      list= where(rez_map==0);
      n= where(rez_map==1);
      if (!numberof(list)) list= [];
      if (!numberof(n)) n= [];
      list= grow(list,n);
      n= numberof(list);

      if (is_void(which)) which= rez_mapi+1;
      else if (!which) which= rez_mapi? rez_mapi : 1;
      else if (which<0) which= rez_mapi>1? rez_mapi-1 : n+1;

      if (!n || which>n) { rez_ding; return; }
      local rr, zz;
      rez_getrz, list(which);

      rn= min(rr);  rx= max(rr);

      zn= min(zz);  zx= max(zz);
      rr= rx-rn;
      zz= zx-zn;
      zn-= 0.3*zz;
      zx+= 0.3*zz;
      rn-= 0.3*rr;
      rx+= 0.3*rr;
      limits, zn, zx, rn, rx;
      rez_mapi= which;
    }

    func rez_prev
    /* DOCUMENT rez_prev

         zoom in on previous bowtied (or chevroned) zone (after rez_mesh).

       SEE ALSO: rez_next, rez_mark, rez_drag
     */
    {
      rez_next, -1;
    }

    func rez_getrz (zlist)
    {

      extern rr, zz;   /* 2-by-2-by-dimsof(zlist) result */
      if (!numberof(zlist)) {
        rr= zz= [];
        return;
      }
      dims= dimsof(rez_rt);
      kmax= dims(2);
      klist= (zlist-1)%(kmax-1);
      llist= (zlist-1)/(kmax-1);
      list= llist*kmax + klist + 1;  /* lower left corner index */

      rr= zz= array(0.0, 2, 2, dimsof(list));
      rr(1,1,..)= rez_rt(list);
      zz(1,1,..)= rez_zt(list);
      rr(2,1,..)= rez_rt(list+1);
      zz(2,1,..)= rez_zt(list+1);
      rr(1,2,..)= rez_rt(list+kmax);
      zz(1,2,..)= rez_zt(list+kmax);
      rr(2,2,..)= rez_rt(list+kmax+1);
      zz(2,2,..)= rez_zt(list+kmax+1);
    }

    func rez_ptexist
    {
      extern rez_ptx, rez_ptlist, rez_ireg;
      rez_ireg(1,)= 0;
      rez_ireg(,1)= 0;
      d= dimsof(rez_ireg);
      ix= d(2);
      jx= d(3);
      n= numberof(rez_ireg);
      ireg= array(0, n+ix+1);
      ireg(1:n)= rez_ireg(*);

      rez_ptx= array(0, dimsof(rez_ireg));
      rez_ptx(*)=
        (ireg(1:n) | ireg(2:n+1) | ireg(ix+1:n+ix) | ireg(ix+2:n+ix+1));
      rez_ptlist= where(rez_ptx);
    }

    extern _rez_center ;

    func rez_find (x, y)
    {
      extern _rez_center;

      d= abs(rez_zt-x, rez_rt-y)(rez_ptlist);
      j= d(mnx);
      d0= d(j);
      j0= rez_ptlist(j);

      j= where(!(d-d0));  /* detect center points */

      if (numberof(j)>1) _rez_center= rez_ptlist(j);
      else _rez_center= [];
      return j0;
    }

    func rez_getvar (f, vars, name)
    {
      v= vars(2);

      if (v && anyof(*v == name)) return get_member(f,name);
      v= vars(1);

      if (v && anyof(*v == name)) return get_member(f,name);
      return [];
    }

    func rez_range (x) { return x; }  /* parser quirk */

    func rez_ding
    {
      write, format="%s", "\a\a";
    }

    func rez_solve (ss, nn)
    /* xxDOCUMENT adapted from gseries_r(s, n) in series.i

         returns the ratio r of the finite geometric series, given the sum s:
            1 + r + r^2 + r^3 + ... + r^(nn-1) = ss,
    	or (r^nn-1)/(r-1) = ss

         Altered to solve only nn>0.0, but allows any real nn.
     */
    {
      /* compute an approximate result which has exact values and
         derivatives at s==1, s==n, and s->infinity --
         different approximations apply for s>n and s<n */
      if (nn==2) return ss-1.0;
      if (ss>nn) {
        pow= 1.0/(nn-1.0);
        npow= nn^pow - 1.0;
        n2r= 1.0/(nn-2.0);
        A= (2.0-nn*npow)*n2r;
        B= (2.0*npow-nn*pow)*nn*n2r;
        r= ss^pow - pow + A*(nn/ss)^pow + B/ss;
      } else {
        sn= (ss-1.0)/(nn-1.0);
        n2r= 1.0/(nn*nn);
        r= 1.0 - 1.0/ss + n2r*sn*sn*(nn+1.0 - sn);
      }

      /* Polish the approximation using Newton-Raphson iterations.  */
      if (ss!=nn) {
        for (;;) {
          rr= r-1.0;
          rn= r^(nn-1);
          rrss= rr*ss;
          delta= rrss - (r*rn-1.0);

          if (abs(delta)<=1.e-9*abs(rrss)) break;
          r+= delta/(nn*rn-ss);
        }
        /* try to get it to machine precision */
        if (delta) r+= delta/(nn*rn-ss);
      }

      return r;
    }

    func rez_test
    {
      extern rez_rt, rez_zt;

      x= span(0,1,10)(,-:1:7);  y= span(0,.5,7)(-:1:10,);
      rez_mesh, x+y, x-y+.5;
    }

    if (!is_void(rez_load_hook)) include, rez_load_hook;