{函数}
function SetScreen(x,y: Word): Boolean;
var
DevMode: TDeviceMode;
begin
Result := EnumDisplaySettings(nil, 0, DevMode);
if Result then
begin
DevMode.dmFields := DM_PELSWIDTH or DM_PELSHEIGHT;
DevMode.dmPelsWidth := x;
DevMode.dmPelsHeight := y;
Result := ChangeDisplaySettings(DevMode, 0) = DISP_CHANGE_SUCCESSFUL;
end;
end;

{测试}
procedure TForm1.Button1Click(Sender: TObject);
begin
SetScreen(1024, 768);
end;