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lib/Acme/Curses/Marquee.pm  view on Meta::CPAN

=head1 SYNOPSIS

Acme::Curses::Marquee implements a scrolling messageboard widget,
using C<figlet> to render the text.

    use Curses;
    use Acme::Curses::Marquee;

    initscr;

    # curses halfdelay mode is what actually drives the display
    # and its argument is what determines the rate of the crawl
    halfdelay(1);

    # spawn subwindow to hold marquee and create marquee object
    my $mw = subwin(9,80,0,0);
    my $m = Acme::Curses::Marquee->new( window => $mw,
                                        height => 9,
                                        width  => 80,
                                        font   => larry3d,
                                        text   => 'hello, world' );

    # then, in the event loop
    while (1) {
        my $ch = getch;
        do_input_processing_and_other_crud();
        $m->scroll;
    }

=head1 METHODS

=head2 new

Creates a new A::C::M object. Three arguments are required:

    * window
    * height
    * width

C<window> should be a curses window that the marquee can write
to. C<height> and C<width> should be the height and width of that
window, in characters.

There are also two optional arguments: C<font>, which sets the figlet
font of the marquee (defaults to the figlet default, 'standard'), and
C<text> which will set an initial string to be displayed and cause the
marquee to start display as soon as it is created.

=cut

sub new {
    my ($class,%args) = @_;

    die "Can't create marquee object without a host window\n" 
        unless( defined $args{window} );
    die "Can't create marquee object without height value\n" 
        unless( defined $args{height} );
    die "Can't create marquee object without width value\n" 
        unless( defined $args{width} );

    my $self = bless { win    => $args{window},
                       height => $args{height},
                       width  => $args{width},
                       font   => $args{font} || 'standard',
                       srctxt => $args{text} || undef, 
                       figtxt => '',
                       txtlen => 0,
                       offset => 0,
                       active => 0,
                     }, $class;

    $self->text($self->{srctext}) if (defined $self->{srctxt});

    return $self;
}

=head2 scroll

Scroll the marquee one position to the right.

=cut

sub scroll {
    my $self = shift;
    my $w    = $self->{win};
    my $x    = $self->{width};
    my $y    = $self->{height};
    my $len  = $self->{txtlen};
    my $off  = $self->{offset};
    my $fig  = $self->{figtxt};

    for (0..$y) { addstr($w, $_, 0, (' ' x $x)) }

    $self->{offset} = 0 if ($self->{offset} == $len);

    foreach my $i (0..(@{$fig} - 1)) {
        if ($off + $x > $len) {
            my $end = $len - $off;
            my $rem   = $x - $end;
            my $tmp = substr($fig->[$i],$off,$end);
            $tmp   .= substr($fig->[$i],0,$rem);
            addstr($w, $i, 0, $tmp);
        } else {
            addstr($w, $i, 0, substr($fig->[$i],$off,$x));
        }
    }
    $self->{offset}++;
    refresh($w);
}

=head2 text

Take a new line of text for the marquee...

   $m->text("New line of text");

...render it via figlet, split it into an array, and perform width
adjustments as neccessary. Store the new text, figleted text, length
of figleted text lines, and set marquee state to active.

=cut