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 Fern(ABitmap: TBitmap);
var
   x, y      : double;        { pixel coordinates }
   i         : integer;       { loop counter}
   q         : integer;       { random number }
   k         : integer;       { row selector }
   MaxY      : integer;
   xValue,
   yValue    : integer;
   MaxY2,
   MaxY10    : double;      { Maximum Y screen coordinate}
   d         : array[1..4,1..6] of double; { holds data of IFS attractor }
   Rect      : TRect;
   Iterations: integer;
begin
  SetRect(Rect, 0, 0, ABitmap.Width, ABitmap.Height);
  with Rect do
  begin
    MaxY := bottom - top;     { find maximum Y coordinate }
    MaxY2 := MaxY/2;
    maxY10 := MaxY/10;
    { initialize IFS data array }
    d[1,1]:=0;    d[1,2]:=0;    d[1,3]:=0;      d[1,4]:=0.16; d[1,5]:=0; d[1,6]:=0;
    d[2,1]:=0.85; d[2,2]:=0.04; d[2,3]:=-0.04; d[2,4]:=0.85; d[2,5]:=0; d[2,6]:=1.6;
    d[3,1]:=0.2;  d[3,2]:=-0.26; d[3,3]:=0.23; d[3,4]:=0.22; d[3,5]:=0; d[3,6]:=1.6;
    d[4,1]:=-0.15; d[4,2]:=0.28; d[4,3]:=0.26; d[4,4]:=0.24; d[4,5]:=0; d[4,6]:=0.44;

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

    Iterations := MaxY * 20; { iteration factor }

    for i := 1 to 10 do                     { skip first 10 iterations }
    begin
      q := random(100) + 1;                 { pick random number from 1-100}
      if q <= 85 then                       { assign row according to }
        k := 2                              { probability }
      else if q = 86 then
        k := 1
      else if (q > 86) and (q < 94) then
        k := 3
      else
        k := 4;

      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
    begin
      q := random(100) + 1;                 { pick random number from 1-100}
      if q <= 85 then                       { assign row according to }
        k := 2                              { probability }
      else if q = 86 then
        k := 1
      else if (q > 86) AND (q < 94) then
        k := 3
      else
        k := 4;

      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];
      xValue := round(MaxY2 + MaxY10*x) + Left;
      yValue := round(MaxY10*y) + Top;

      ABitmap.Canvas.Pixels[xValue,yValue] := ABitmap.Canvas.Pen.Color;
    end;                                { scale for screen }
  end;
end;

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



� 2004 Jim Valavanis