sub SetBigText {
my ($widget, $text) = @_;

my $font =     $widget->Font ();
my $widthF =   $widget->fontMeasure ($font, $text);
my $heightF =  $widget->fontMetrics($font, -linespace);
my $xRatio =   $widget->width / $widthF;
my $yRatio =   $widget->height / $heightF;
my $minRatio = $xRatio < $yRatio ? $xRatio : $yRatio;
my $fontSize = $widget->fontActual ($font, -size);
my $newSize =  $minRatio * $fontSize;

$font->configure   (-size => $newSize);
$widget->configure (-text => $text);
$widget->configure (-font => $font);
}