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;