Mathematisches problem: Achsenkreuz

[theomega]

wenn ich das wüsste, was nicht geht, der code spinnt manchmal einfach rum!
aber ich poste ihn hier mal:

Delphi-Quellcode:

unit AchsenKreuz;

interface

uses
  SysUtils, Classes, Controls, ExtCtrls,Dialogs,Graphics;


type TEPoint=record
  x,y:extended;
end;

type TEPixel=record
  x,y:integer;
  col:TColor;
end;

type
  TAchsenKreuz = class(TPaintBox)
  private
    { Private-Deklarationen }

    Ffrom_x: extended;
    Fto_y: extended;
    Fto_x: extended;
    Ffrom_y: extended;

    t_width,t_height:extended;


    Fdraw_axes: boolean;

    td_pixels:array of TEPixel;
    Faxes_color: TColor;

    procedure Setfrom_x(const Value: extended);
    procedure Setfrom_y(const Value: extended);
    procedure Setto_x(const Value: extended);
    procedure Setto_y(const Value: extended);

    procedure init_values();
    procedure Setdraw_axes(const Value: boolean);
    procedure Setaxes_color(const Value: TColor);
  protected
    { Protected-Deklarationen }
  public
    { Public-Deklarationen }
    //Public zu Debug-Zwecken
    x_scale,y_scale:extended;
    org:TEPoint;

    constructor Create(AOwner: TComponent); override;
    procedure Paint; override;
    procedure draw_point(x,y:extended;col:TColor);
    function pix2point(px,py:integer):TEPoint;
    procedure loschen;
  published
    { Published-Deklarationen }
    property from_x:extended read Ffrom_x write Setfrom_x;
    property to_x:extended read Fto_x write Setto_x;
    property from_y:extended read Ffrom_y write Setfrom_y;
    property to_y:extended read Fto_y write Setto_y;
    property draw_axes:boolean read Fdraw_axes write Setdraw_axes;
    property axes_color:TColor read Faxes_color write Setaxes_color;

  end;

procedure Register;

implementation


constructor TAchsenKreuz.Create(AOwner: TComponent);
begin;
//Bis jetzt noch unütz
setlength(td_pixels,0);
inherited Create(AOwner);
end;


procedure TAchsenKreuz.Paint;
var i:integer;
begin;
init_values;

//Bis jetz noch unütz
for i:= low(td_pixels) to high(td_pixels) do begin;
  canvas.Pixels[td_pixels[i].x,td_pixels[i].y] := td_pixels[i].col;
end;

if (Fdraw_axes) then begin;
  Canvas.Pen.Color := Faxes_color;
  canvas.Pen.Style := psSolid;
  Canvas.MoveTo(round(org.X),0);
  Canvas.LineTo(round(org.X),height);

  Canvas.MoveTo(0,round(org.y));
  Canvas.LineTo(width,round(org.y));
end;


end;

procedure TAchsenKreuz.draw_point(x,y:extended;col:TColor);
begin;
//Bis jetzt noch unütz
{setlength(td_pixels,length(td_pixels)+1);
td_pixels[high(td_pixels)].x := round(org.x + x*x_scale);
td_pixels[high(td_pixels)].y := round(org.y - y*y_scale);
td_pixels[high(td_pixels)].col := col;
}
canvas.Pixels[round(org.x + x*x_scale),round(org.y - y*y_scale)] := col;
paint;
end;

//Wandelt Delphi Pixel in Achsenkreu Koordinaten um 
function TAchsenKreuz.pix2point(px,py:integer):TEPoint;
begin;
if ((x_scale>0) AND (y_scale>0)) then begin;
result.x := (px-org.x)/x_scale;
result.y := (-py+org.y)/y_scale;
end
else begin;
  result.x := 99999;
  result.y := 99999;
end
end;

//löscht die paintbox
procedure TAchsenKreuz.loschen;
begin;
canvas.Brush.Color := color;
canvas.Pen.Style := psClear;
canvas.Rectangle(0,0,width,height);
end;

procedure Register;
begin
  RegisterComponents('Beispiele', [TAchsenKreuz]);
end;

//Berechnungen
procedure TAchsenKreuz.init_values;
begin
  t_width := abs(ffrom_x)+abs(fto_x);
  t_height:= abs(ffrom_y)+abs(fto_y);

  if ((t_width>0) AND (t_height>0)) then begin;
    try
      x_scale:=Width / t_width;
    except
      on E: Exception do
        messagedlg('XScale '+floattostr(x_scale)+'/'+floattostr(t_width)+' '+ E.Message,mterror,[mbok],0);
    end;

    try
      y_scale:=self.Height / t_height;
    except
      on E: Exception do
        messagedlg('YScale '+floattostr(Y_scale)+'/'+floattostr(t_height)+' '+ E.Message,mterror,[mbok],0);
    end;
    org.X := ffrom_x*(-1)*x_scale;
    org.y := fto_y*y_scale;
  end;

end;

procedure TAchsenKreuz.Setdraw_axes(const Value: boolean);
begin
  Fdraw_axes := Value;
  init_values;
end;

procedure TAchsenKreuz.Setfrom_x(const Value: extended);
begin
  Ffrom_x := Value;
  init_values;
end;

procedure TAchsenKreuz.Setfrom_y(const Value: extended);
begin
  Ffrom_y := Value;
  init_values;
end;

procedure TAchsenKreuz.Setto_x(const Value: extended);
begin
  Fto_x := Value;
  init_values;
end;

procedure TAchsenKreuz.Setto_y(const Value: extended);
begin
  Fto_y := Value;
  init_values;
end;

procedure TAchsenKreuz.Setaxes_color(const Value: TColor);
begin
  Faxes_color := Value;
end;

end.

irgendwie scheinen manche ausschnitte probleme zu bereiten, ich kann aber das nicht näher bestimmen welche!
Ich bezweifle auch, dass jemand meinen (sicher schlecht geschriebenen) code versteht!

Grüße und Danke
TO