Smoth resize einer Bitmap mit dieser Funktion ?

[thomas2009]

Hallo

ich habe diese Funktion von DelphiSwiss hier
Es passiert aber nichts :

Delphi-Quellcode:

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls;
 
type
  TRGBArray = array[Word] of TRGBTriple;
  pRGBArray = ^TRGBArray;
 
 
type
  TForm1 = class(TForm)
    Image1: TImage;
    Image2: TImage;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
procedure SmoothResize(Src, Dst: TBitmap);
var
  x, y: Integer;
  xP, yP: Integer;
  xP2, yP2: Integer;
  SrcLine1, SrcLine2: pRGBArray;
  t3: Integer;
  z, z2, iz2: Integer;
  DstLine: pRGBArray;
  DstGap: Integer;
  w1, w2, w3, w4: Integer;
begin
  Src.PixelFormat := pf24Bit;
  Dst.PixelFormat := pf24Bit;
 
  if (Src.Width = Dst.Width) and (Src.Height = Dst.Height) then
    Dst.Assign(Src)
  else
  begin
    DstLine := Dst.ScanLine[0];
    DstGap  := Integer(Dst.ScanLine[1]) - Integer(DstLine);
 
    xP2 := MulDiv(pred(Src.Width), $10000, Dst.Width);
    yP2 := MulDiv(pred(Src.Height), $10000, Dst.Height);
    yP  := 0;
 
    for y := 0 to pred(Dst.Height) do
    begin
      xP := 0;
 
      SrcLine1 := Src.ScanLine[yP shr 16];
 
      if (yP shr 16 < pred(Src.Height)) then
        SrcLine2 := Src.ScanLine[succ(yP shr 16)]
      else
        SrcLine2 := Src.ScanLine[yP shr 16];
 
      z2  := succ(yP and $FFFF);
      iz2 := succ((not yp) and $FFFF);
      for x := 0 to pred(Dst.Width) do
      begin
        t3 := xP shr 16;
        z  := xP and $FFFF;
        w2 := MulDiv(z, iz2, $10000);
        w1 := iz2 - w2;
        w4 := MulDiv(z, z2, $10000);
        w3 := z2 - w4;
        DstLine[x].rgbtRed := (SrcLine1[t3].rgbtRed * w1 +
          SrcLine1[t3 + 1].rgbtRed * w2 +
          SrcLine2[t3].rgbtRed * w3 + SrcLine2[t3 + 1].rgbtRed * w4) shr 16;
        DstLine[x].rgbtGreen :=
          (SrcLine1[t3].rgbtGreen * w1 + SrcLine1[t3 + 1].rgbtGreen * w2 +
 
          SrcLine2[t3].rgbtGreen * w3 + SrcLine2[t3 + 1].rgbtGreen * w4) shr 16;
        DstLine[x].rgbtBlue := (SrcLine1[t3].rgbtBlue * w1 +
          SrcLine1[t3 + 1].rgbtBlue * w2 +
          SrcLine2[t3].rgbtBlue * w3 +
          SrcLine2[t3 + 1].rgbtBlue * w4) shr 16;
        Inc(xP, xP2);
      end; {for}
      Inc(yP, yP2);
      DstLine := pRGBArray(Integer(DstLine) + DstGap);
    end; {for}
  end; {if}
end; {SmoothResize}
 
{---------------------------------------------------------------------------
-----------------------}
 
procedure TForm1.Button1Click(Sender: TObject);
begin
SmoothResize(Image1.Picture.Bitmap, Image2.Picture.Bitmap);
end;
 
end.

Ich wollte damit die Bitmap verkleinern/vergrößern