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const
  
escape=4.0;                { escape value }
  
attract=0.0001;            { attractor sensitivity }

const
  
Black        = 0;
   Blue         = 1;
   Green        = 2;
   Cyan         = 3;
   Red          = 4;
   Magenta      = 5;
   Brown        = 6;
   LightGray    = 7;
   DarkGray     = 8;
   LightBlue    = 9;
   LightGreen   =10;
   LightCyan    =11;
   LightRed     =12;
   LightMagenta =13;
   Yellow       =14;
   White        =15;

function GetRGBColor(color:byte):longint;
begin
  case
Color of
   
black : GetRGBColor := RGB(0,0,0);
    blue  : GetRGBColor := RGB(0,0,128);
    green : GetRGBColor := RGB(0,128,0);
    cyan  : GetRGBColor := RGB(0,255,255);
    red   : GetRGBColor := RGB(128,0,0);
    magenta : GetRGBColor := RGB(128,0,128);
    brown : GetRGBColor := RGB(128,128,0);
    lightgray : GetRGBColor := RGB(192,192,192);
    darkgray : GetRGBColor := RGB(128,128,128);
    lightBlue : GetRGBColor := RGB(0,0,255);
    lightGreen : GetRGBColor := RGB(0,255,0);
    lightcyan : GetRGBColor := RGB(0,255,255);
    lightRed : GetRGBColor := RGB(255,0,0);
    lightmagenta : GetRGBColor := RGB(255,0,255);
    yellow: GetRGBColor := RGB(255,255,0);
    white : GetRGBColor := RGB(255,255,255);
  else
   
GetRGBColor := RGB(0,0,255);
  end;
end;

////////////////////////////////////////////////////////////////////////////////

procedure Tree(ABitmap: TBitmap);
{ compute and display a tree
  using Michael Barnsley's IFS algorithm
  31-6-94  Valavanis Jim                   }
var
  
x, y      : double;        { pixel coordinates }
  
i         : integer;       { loop counters}
  
q         : integer;       { random number }
  
k         : integer;       { row selector }
  
MaxX,
   MaxY      : integer;      { Maximum X screen coordinate}
  
d         : array[1..4,1..6] of double; { holds data of IFS attractor }
  
scale     : double;        { random scale factor}
  
xpos,ypos : integer;      { tree position }
  
Rect      : TRect;
   Iterations: integer;
   xValue,
   yValue    : integer;
   xScale,
   yScale : double;
begin
 
SetRect(Rect, 0, 0, ABitmap.Width, ABitmap.Height);
  with Rect do
  begin
   
MaxX := right - left;
    MaxY := bottom - top;     { find maximum Y coordinate }
   
if (MaxX=0) or (MaxY=0) then exit;
    MaxX := Min(MaxX,MaxY);
    MaxY := MaxX;
    right := left + MaxX;
    bottom := top + MaxY;
{ initialize IFS data array }

   
d[1,1]:=0;     d[1,2]:=0;     d[1,3]:=0;      d[1,4]:=0.5;  d[1,5]:=0; d[1,6]:=0;
    d[2,1]:=0.42;  d[2,2]:=-0.42; d[2,3]:=0.42;  d[2,4]:=0.42; d[2,5]:=0; d[2,6]:=0.2;
    d[3,1]:=0.42;  d[3,2]:=0.42;  d[3,3]:=-0.42; d[3,4]:=0.42; d[3,5]:=0; d[3,6]:=0.2;
    d[4,1]:=0.1;   d[4,2]:=0;     d[4,3]:=0;      d[4,4]:=0.1;  d[4,5]:=0; d[4,6]:=0.2;

    x := 0;               {set starting coordinates}
   
y := 0;

    Iterations := MaxX * 25;

    xpos := MaxX div 2;          { pick tree position }
   
ypos := MaxY;
    scale := MaxX*3;                     { pick tree scale }

   
for i := 1 to 10 do                  { skip first 10 iterations }
   
begin
     
q := random(100) + 1;              { pick random number from 1-100}
     
if q <= 40 then                    { assign row according to }
       
k := 2                          { probability }
     
else if (q> 40) and (q < 81) then
       
k := 3
     
else if (q >= 81) and (q < 95) then
       
k := 4
     
else
       
k := 1;

      x := d[k,1]*x + d[k,2]*y + d[k,5];   { transform coordinates }
     
y := d[k,3]*x + d[k,4]*y + d[k,6];
    end;

    for i := 11 to iterations do             { Iterations pixels per tree }
   
begin
     
q := random(100) + 1;                 { pick random number from 1-100}
     
if q <= 40 then                       { assign row according to }
       
k := 2                              { probability }
     
else if (q> 40) and (q < 81) then
       
k := 3
     
else if (q >= 81) and (q < 95) then
       
k := 4
     
else
       
k := 1;

      x := d[k,1]*x + d[k,2]*y + d[k,5];   { transform coordinates }
     
y := d[k,3]*x + d[k,4]*y + d[k,6];

      xScale := x*scale;
      yScale := y*scale;
      if (xScale<maxLong) and (yScale<maxLong) then
      begin
       
xValue := xpos + round(xScale);
        yValue := ypos - round(yScale);

        ABitmap.Canvas.Pixels[xValue + Left,yValue + top] := ABitmap.Canvas.Pen.Color;
      end;
    end;
  end;
end;

////////////////////////////////////////////////////////////////////////////////


2004 Jim Valavanis

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