Delphi内的图片缩放的实现

procedure ResizeBmp(Src,Dst:String);
var SrcBM,DstBM:TBitMap;
    Rect:TRect;
    NewW,NewH,PicW,PicH:Integer;
    HDivW:Double;
begin
  SrcBM:=TBitMap.Create;
  SrcBM.LoadFromFile(Src);
  PicW:=SrcBM.Width;
  PicH:=SrcBM.Height;
  NewH:=768;
  NewW:=1024;
  DstBM:=TBitMap.Create;
  with DstBM do begin
    Width:=NewW;
    Height:=NewH;
    Rect.TopLeft:=Point(0,0);
    Rect.BottomRight:=Point(NewW,NewH);
    Canvas.Rectangle(0,0,Width,Height);
    Canvas.StretchDraw(Rect,TGraphic(SrcBM));
    SaveToFile(Dst);
    FreeImage;
    Free;
  end;
end;