% `rotellipse.m4'
.PS
gen_init

divert(-1)
                                `rotellipse( width, height, type )
                                 ellipse oriented in current direction;
                                 type= eg dotted fill_(0.9)'
define(`rotellipse',
`[define(`m4ehw',(ifelse(`$1',,ellipsewid,`($1)')/2))dnl
  define(`m4ehh',(ifelse(`$2',,ellipseht,`($2)')/2))dnl
  spline ifdpic(
   `0.551784 `$3' from vec_(0,-m4ehh) \
      to vec_(m4ehw,-m4ehh) \
      then to vec_(m4ehw,m4ehh) \
      then to vec_(-m4ehw,m4ehh) \
      then to vec_(-m4ehw,-m4ehh) \
      then to vec_(0,-m4ehh)',
   ``$3' from vec_(0,-m4ehh) to vec_(m4ehw/64,-m4ehh) \
      for_(1,31,1,
       `then to vec_(m4ehw*sin(twopi_*m4x/32),-m4ehh*cos(twopi_*m4x/32))\') \
        then to vec_(-m4ehw/64,-m4ehh) \
        then to vec_(0,-m4ehh)')
    `$4' ] wid 2*sqrt((m4a_*m4ehw)^2+(m4b_*m4ehh)^2) \
      ht  2*sqrt((m4c_*m4ehw)^2+(m4d_*m4ehh)^2)')
divert(0)dnl

[
  ifpostscript(defineRGBprimaries)
  
  [
    E: ellipse shaded "red" outlined "blue"
    
    A: rotellipse(1,1,outlined "red" shaded "blue") with .w at E.e
      Point_(45)
    B: rotellipse(,,dotted fill_(0.9))
    C: rotellipse(,,colored "red") with .s at last [].n
    thinlines_
    showbox_(A)
    showbox_(B)
    showbox_(C)
    thicklines_
    ]
  
  [
    for_(0,9,1,
     `Point_(m4x/10*360)
      B: lbox(boxwid/2,boxht/2,colored "red")
      thinlines_
      showbox_(B)
      thicklines_ ')
    
    move to Here + (1.5,0)
    arc fill
    arc to Here-(2*arcrad,0) outlined "red" shaded "green"
    ] with .nw at last [].sw + (0,-0.5)

] with .sw at 1,1

.PE