谁能帮我分析这段截代码?
wzwcn 2003-11-22 06:10:21 procedure TForm1.Button1Click(Sender: TObject);
var bitmap:tbitmap;
canva:tcanvas;
dc:hdc;
begin
bitmap:=tbitmap.Create ;
canva:=tcanvas.Create ;
dc:=getdc(0);
bitmap.Width:=screen.Width ;
bitmap.Height:=screen.Height ;
canva.Handle:=dc;
bitmap.Canvas.CopyRect(rect(0,0,screen.Width,screen.Height),canvas,rect(0,0,screen.Width,screen.Height));
image1.Picture.Bitmap:=bitmap;
canvas.Free;
bitmap.Free;
deletedc(dc);
end;