//This is a drawing program

U0 Doodle()
{
  I64 msg_code,i,x1,y1,x2,y2,arg1,arg2,color=BLACK;
  CDC *dc=DCAlias;
  SettingsPush; //See SettingsPush
  Fs->win_inhibit=WIG_TASK_DFT-WIF_SELF_FOCUS-WIF_SELF_BORDER;
  AutoComplete;
  WinBorder;
  WinMax;
  DocClear;
  DCFill;
  do
  {
    msg_code=GetMsg(&arg1,&arg2,
                    1<<MSG_KEY_DOWN+1<<MSG_MS_L_DOWN+1<<MSG_MS_R_UP);
    switch (msg_code)
    {
    case MSG_MS_R_UP:
      i=PopUpColor;
      if (i>=0) color=i;
      break;
    case MSG_MS_L_DOWN:
      x1=arg1;
      y1=arg2;
      x2=arg1;
      y2=arg2;
      dc->color=ROP_XOR+color^TRANSPARENT;
      dc->thick=7;
      do
      {
        GrLine3(dc,x1,y1,0,x2,y2,0);
        msg_code=GetMsg(&arg1,&arg2,1<<MSG_MS_L_UP+1<<MSG_MS_MOVE);
        GrLine3(dc,x1,y1,0,x2,y2,0);
        x2=arg1;
        y2=arg2;
      }
      while (msg_code!=MSG_MS_L_UP);
      GrLine3(dc,x1,y1,0,x2,y2,0);
      break;
    case MSG_KEY_DOWN:
      break;
    }
  }
  while (msg_code!=MSG_KEY_DOWN || !arg1);
  GetMsg(,,1<<MSG_KEY_UP);
  DCFill;
  DCDel(dc);
  SettingsPop;
}

Doodle;  //Execute when #included