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From: rob@siesoft (rob)
Newsgroups: comp.lang.postscript
Subject: Bezier trees
Message-ID: <1189@argon.siesoft>
Date: 9 Mar 89 11:17:37 GMT
Reply-To: rob@.UUCP ()
Organization: Siemens SDG, woodley, England
Lines: 86

I've been reading this group with interest for a few weeks now and I thought 
some of you might be interested in a little program to draw trees - I start
with a "curveto" curve and then recurse at a number of points on the curve.
WARNING - don't try this unless  your printer is otherwise unoccupied for a
half hour or so!! I've also written a similar program in C to generate "flat"
Postscript output. This allows me to "solve" the curve on the fly and tamper
with each "branch" to my heart's content - I found the prospect of solving
cubic equations in postfix rather daunting! If you've got any suggestions
for improvements (this is my first Postscript program) or you'd like the "C"
version please let me know. You can of course hack this to draw single
trees - the largest sensible recursion depth is 5 (about a half hour). A
depth of 3 takes a several minutes.

Rob Henley
Siemens SDG

8-< -------------------------------------------------------------------------


% ------- Variables & Procedures --------
/depth    0 def
/maxdepth 5 def
/down {/depth depth 1 add def} def
/up   {/depth depth 1 sub def} def

/tree
{
  gsave
  translate       % new user space
  rotate          % rotate
  .3  .3  scale   % reduce scale
  0 0 moveto      % move to origin
  6 copy          % copy 6 top items
  curveto         % Bezier cubic
  stroke          % mark the path

  % -- recurse at points calculated to be on the curve --
  down
  depth maxdepth le
  {
    60 12.5 262.5 tree
    -60 28.8 331.2 tree
    60 25.9 401.1 tree
    -40 -6.4 470.4 tree
    90 -78.3 537.3 tree
    -40 -132.3 569.3 tree
    70 -200 600 tree
    -15 -200 600 tree
  } if
  up
  grestore
} def


/season
{
gsave
translate
/maxdepth exch def
200 100 translate
-200 100    300 400    -200 600    0 0 0 tree
grestore
} def


/printbanner
{180 20 moveto (Winter Spring Summer) show} def


% ------- Begin Program --------
newpath

/Times-Italic findfont 30 scalefont setfont
.95 -.05 0 {setgray printbanner -1 .5 translate} for
1 setgray 
printbanner

0 setgray
0 0 moveto 

2 0   350 season
3 300 350 season
4 0   0   season
5 300 0   season

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