Example 15.9: tcapdemo

#!/usr/bin/perl -w # 

tcapdemo - show off direct cursor placement  use POSIX; use Term::Cap;      init();                     # Initialize Term::Cap. zip();                      # Bounce lines around the screen. finish();                   # Clean up afterward. exit();  # Two convenience functions.  clear_screen is obvious, and # clear_end clears to the end of the screen. sub clear_screen { $tcap->Tputs('cl', 1, *STDOUT) }  sub clear_end    { $tcap->Tputs('cd', 1, *STDOUT) }   # Move the cursor to a particular location. sub gotoxy {     my($x, $y) = @_;     $tcap->Tgoto('cm', $x, $y, *STDOUT); }   # Get the terminal speed through the POSIX module and use that # to initialize Term::Cap. sub init {      $| = 1;     $delay = (shift() || 0) * 0.005;     my $termios = POSIX::Termios->new();     $termios->getattr;     my $ospeed = $termios->getospeed;     $tcap = Term::Cap->Tgetent ({ TERM => undef, OSPEED => $ospeed });     $tcap->Trequire(qw(cl cm cd)); }  # Bounce lines around the screen until the user interrupts with # Ctrl-C. sub zip {      clear_screen();     ($maxrow, $maxcol) = ($tcap->{_li} - 1, $tcap->{_co} - 1);      @chars = qw(* - / | \ _ );     sub circle { push(@chars, shift @chars); }      $interrupted = 0;     $SIG{INT} = sub { ++$interrupted };      $col = $row = 0;     ($row_sign, $col_sign) = (1,1);      do {         gotoxy($col, $row);         print $chars[0];         select(undef, undef, undef, $delay);          $row += $row_sign;         $col += $col_sign;          if    ($row == $maxrow) { $row_sign = -1; circle; }          elsif ($row == 0 )      { $row_sign = +1; circle; }          if    ($col == $maxcol) { $col_sign = -1; circle; }          elsif ($col == 0 )      { $col_sign = +1; circle; }          } until $interrupted;  }  # Clean up the screen. sub finish {      gotoxy(0, $maxrow);     clear_end(); }