anchor.diff:      chroma1 = 40.0
       chroma2 = 40.0
       ncolors = 10
  +    convert1 = ''
  +    convert2 = ''
       vrb = 0
       narg = iargc()
       if (narg.eq.0) call usage('')
  
positive.code:             elseif (ch1.eq.'y') then
                  hue1 = 90
              elseif (ch1.eq.'g') then
                  hue1 = 150
              elseif (ch1.eq.'b') then
                  hue1 = 270
              elseif (ch1.eq.'p') then
  
negative.code:         write(0,*) str
          write(0,*)
      endif
      write(0,*) 'Usage: colortool -cmap OPTION [-hue H1,H2] [-lightness L1,L2] [-chroma C1,C2] [-ncolors N]'
      write(0,*) '                 [-convert ITYP=X,Y,Z OTYP] [-v verbose] [-d]'
      write(0,*)
      write(0,*) '-cmap OPTION              Generate a perceptually linear colormap'
      if (str.eq.'long') then
          write(0,*) '    spiral: rotate through hues in lightness-chroma-hue space (r->o->y->g->b->p)'
          write(0,*) '    linear: draw line through lightness-a-b space (a=chroma*cos(hue), b=chroma*sin(hue))'
          write(0,*)
      endif
      write(0,*) '-hue H1,H2                Starting and ending hues (default: 0,360)'
      if (str.eq.'long') then
          write(0,*) '    Can also define hues with color names or first letters'
          write(0,*) '        0=360  "magenta"'
          write(0,*) '        30     "red"'
          write(0,*) '        50     "orange"'
          write(0,*) '        90     "yellow"'
          write(0,*) '        140    "green"'
          write(0,*) '        270    "blue"'
          write(0,*) '        330    "purple"'
          write(0,*)
      endif
      write(0,*) '-lightness L1,L2          Starting and ending hues (default: 0,100)'
      if (str.eq.'long') then
          write(0,*)
      endif
      write(0,*) '-chroma C1,C2             Starting and ending chroma (default: 40,40)'
      if (str.eq.'long') then
          write(0,*) '    Chroma is similar to saturation; its max value depends on hue and lightness'
          write(0,*) '    0=grey, max=full color'
          write(0,*) '    The max chroma will be limited by the program automatically'
          write(0,*)
      endif
      write(0,*) '-ncolors N                Number of colors (default: 10)'
      if (str.eq.'long') then
          write(0,*)
      endif
      write(0,*) '-convert ITYP=X,Y,Z OTYP  Convert a color of type ITYP to type OTYP (does not print colors)'
      if (str.eq.'long') then
          write(0,*) '    Available color types: lch, lab, rgb (planning to implement hsv eventually)'
          write(0,*)
      endif
      write(0,*) '-verbose                  Turn on verbose mode'
      if (str.eq.'long') then
          write(0,*)
      endif
      write(0,*) '-d                        Detailed help'
      stop
  return
  end
  