unit Unit7;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, Grafisch, Contours;

type
  TForm1 = class(TForm)
    Image1: TImage;
    procedure Toetsdruk(Sender: TObject; var Key: Char);
    procedure Scheppen(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

function macht(x,p : double) : double;
begin
  macht := exp(ln(x)*p);
end;

procedure Schetsen(eps : double);
const
  grens : integer = 75;
var
  i,j,k,g,ii,jj : integer;
  x,y,f : double;
  min,max,nivo : double;
  bewaar : array of array of double;
  O : Omtrekken;
begin
  ClearDevice;
  min := 10; max := -10;
  SetLength(bewaar,Wijd,Hoog);
  ii := 0; jj := 0;
  for j := 0 to Hoog-1 do
  begin
    y := j2y(j);
    for i := 0 to Wijd-1 do
    begin
      x := i2x(i);
      f := x/macht(4*(sqr(y)*y+1),1/3)
         + y/(x+1) + 1/(x+y)
         - sqrt(9/4+sqr(x-y)/(x*y+x+y));
      if max < f then max := f;
      if min > f then
      begin
        min := f; ii := i; jj := j;
      end;
      bewaar[i,j] := f;
    end;
  end;
  Writeln(min,' < f <',max);
  Writeln('f(',i2x(ii),',',j2y(jj),') = ',min);
  O := Omtrekken.Create;
  O.Scherm := Form1.Image1.Picture.Bitmap;
  O.afmetingen(Wijd,Hoog);
  for j := 0 to Hoog-1 do
  begin
    for i := 0 to Wijd-1 do
    begin
      Form1.Image1.Canvas.Pixels[i,j] :=
      Grijs((bewaar[i,j]-min)/(max-min));
      if bewaar[i,j] < eps then
      Form1.Image1.Canvas.Pixels[i,j] := clBlue;
    end;
  end;
  for g := 0 to grens do
  begin
    nivo := min + (g/grens)*(max-min);
    for j := 0 to Hoog-1 do
    begin
      for i := 0 to Wijd-1 do
      begin
        O.funktie[i,j] := bewaar[i,j]-nivo;
      end;
    end;
    O.Rondom(false);
    for k := 0 to O.Aantal do
      O.Schetsen(k,Grijs((max-nivo)/(max-min)),2);
  end;
end;

procedure TForm1.Toetsdruk(Sender: TObject; var Key: Char);
begin
  Exit;
end;

procedure TForm1.Scheppen(Sender: TObject);
begin
  xmin := 0; xmax := 2;
  ymin := 1; ymax := 2;
  TV(Form1.Image1);
  ClearDevice;
  Schetsen(0.001);
  Form1.Image1.Picture.SaveToFile('jensen.bmp');
end;

end.