不明白 scanline的出有关问题;小弟我估计是指针引起的;但是找不出解决办法;help!

不明白 scanline的出问题;我估计是指针引起的;但是找不出解决方法;help!~~~~~~~

Delphi(Pascal) code

var  i,j,m,dc,whd:Integer;  Pee,Pff : PByteArray;  bmptmp,bmp1:tbitmap;begin   whd:= FindWindow(nil,'Micka');  if whd=0 then Exit;  dc:=GetWindowDC(whd);  bmp1:=TBitmap.Create;  bmp1.PixelFormat:=pf24bit;  bmp1.Width:=22;  bmp1.Height:=34;  BitBlt(bmp1.Canvas.Handle,0,0,bmp1.Width,bmp1.Height,dc,154,30,SRCCOPY);  if bmp1=nil then exit;  bmptmp:=tbitmap.Create;  bmptmp.PixelFormat:=pf24bit;  try    for  m:=0 to 4 do    begin //页面上有 5张imgage的bmp的比较图      bmptmp:=(self.FindComponent('img'+inttostr(m+1)) as Timage).Picture.Bitmap;      Pee:=nil;      Pff:=nil;     // for  j:=30 to 62 do      for  j:=0 to 32 do      begin        Pee:=bmp1.ScanLine[j];        Pff:=bmptmp.ScanLine[j];         for  i:=0 to 20 do        begin          if Round((Pee[i * 3 + 2]  + pee[i * 3 + 1]  + pee[i* 3])/3)<>            Round((Pff[(i) * 3 + 2]  + pff[(i) * 3 + 1]  + pff[(i)* 3])/3) then             begin              break;            end;        end;        if i<=20 then//找到不同的  174          break;      end;      if j>=32 then //找到xiang同的 62      begin         exit;      end;    end;  finally    bmp1.Free;    bmptmp.Free;  end;