如何把屏幕的一部分copy下来？

Question

试试下面的函数：
function ScreenCapture(X1,Y1,X2,Y2: Integer): HBitmap;
var
  Width,Height: Integer;
  SourceDC,DestDC,BHandle: Integer;
begin
  Width:=x2-x1;
  Height:=y2-y1;
  SourceDC:=CreateDC('DISPLAY','','',nil);
  DestDc:=CreateCompatibleDC(SourceDC);
  BHandle:=CreateCompatibleBitmap(SourceDC,Width,Height);
  SelectObject(DestDC,BHandle);
  BitBlt(DestDC,0,0,Width,Height,SourceDC,X1,Y1,SRCCOPY);
  DeleteDC(DestDC);
  ReleaseDC(BHandle,SourceDC);
  Result:=BHandle;
end;