package Hello;
use QColor;
use QObject;
use QPainter;
use QPixmap;
use QPushButton;
use QTimer;
use QWidget;
use signals 'clicked()';
use slots 'animate()';
@ISA = qw(QWidget);
sub new {
    my $self = shift->SUPER::new(@_[1..$#_]);
    @$self{'t', 'b'} = (shift, 0);
    $timer = new QTimer($self);
    $self->connect($timer, 'timeout()', 'animate()');
    $timer->start(40);
    $self->resize(200, 100);
    return $self;
}
sub animate {
    my $self = shift;
    $$self{'b'} = ($$self{'b'}+1) & 15;
    $self->repaint(0);
}
sub mouseReleaseEvent {
    my $self = shift;
    my $e = shift;
    emit $self->clicked() if $self->rect()->contains($e->pos());
}
{
    my @sin_tbl = (0, 38, 71, 92, 100, 92, 71, 38, 0, -38, -71, -92,
                   -100, -92, -71, -38);
    sub paintEvent {
        my $self = shift;
        my $t = $$self{'t'};
        return unless $t;
        my $fm = $self->fontMetrics();
        my $w = $fm->width($t) + 20;
        my $h = $fm->height() * 2;
        my $pmx = $self->width()/2 - $w/2;
        my $pmy = $self->height()/2 - $h/2;
        my $pm = new QPixmap($w, $h);
        $pm->fill($self, $pmx, $pmy);
        $p = new QPainter;
        my $x = 10;
        my $y = $h/2 + $fm->descent();
        my $i = 0;
        $p->begin($pm);
        $p->setFont($self->font());
        my $i16;
        my $index = 0;
        my $length = length($t);
        while($index < $length) {
            $_ = substr($t, $index++, 1);
            $i16 = ($$self{'b'}+$i) & 15;
            $p->setPen(new QColor((15-$i16)*16, 255, 255, $Spec{Hsv}));
            $p->drawText($x, $y-$sin_tbl[$i16]*$h/800, substr($t, $i), 1);
            $x += $fm->width($_);
            $i++;
        }
        $p->end();
        $self->bitBlt($pmx, $pmy, $pm);
    }
}