my $can = PCI::Telnet::GUI::Canvas->new(10,40);
$can->fill([ON_YELLOW,BOLD,WHITE],0,0,$can->height,$can->width,HOR);

my $c2 = PCI::Telnet::Canvas->new(5,10);
$c2->box(0,0,$c2->height-2,$c2->width-2,ON_WHITE,BLACK,1);

$can->render_canvas(2,2,$c2);
print $can->to_string(20,10), "\n\n";

##</code><code>##

use constant AS_BG    => 0;
use constant AS_FG    => 1;
use constant AS_U     => 2;
use constant AS_BLINK => 3;
use constant AS_BOLD  => 4;

# clone is from the Clone module on CPAN. Tried using Clone::Fast, but it added .05 sec to running time when this function was called ~6000x in .25 seconds.

sub _atlayer
{
	#$_[0] = shift;
	local $_ = clone($_[1]);
	#$_->{$_} = $_[1]->{$_} foreach keys %{$_[1]};
	$_->[AS_BG]	= $_[0]->[AS_BG]	if !$_->[AS_BG];
	$_->[AS_FG]	= $_[0]->[AS_FG]	if !$_->[AS_FG];
	$_->[AS_U]	= $_[0]->[AS_U]		if  $_->[AS_U] < 0;
	$_->[AS_BOLD]	= $_[0]->[AS_BOLD]	if  $_->[AS_BOLD] < 0;
	$_->[AS_BLINK]	= $_[0]->[AS_BLINK]	if  $_->[AS_BLINK] < 0;
	return $_;
}

##</code><code>##

# iloop is the inner loop of the canvas rendering function. 
# I put it in a separate sub so that DProf could show it
# apart from the main loop - and it gets 79% of the 
# processing time under one scenario.
sub iloop($$$)
{
	my ($line,$arow,$sw,$lat,$blank) = @_;
	my ($atr,$chr,$col,@a);
	for $col (0..$sw)
	{
		$chr = $line->[$col];
		$atr = $arow->[$col];
		
		push @a, _attr($atr) if #!_ateq($lat,$atr);
				$lat->[AS_BG]		ne $atr->[AS_BG] ||
				$lat->[AS_FG]		ne $atr->[AS_FG] ||
				$lat->[AS_U]		!= $atr->[AS_U]  ||
				$lat->[AS_BOLD]		!= $atr->[AS_BOLD] ||
				$lat->[AS_BLINK]	!= $atr->[AS_BLINK];

		push @a, defined $chr ? $chr : $blank;

		$lat = $atr;

	}
	return join '', @a;
}