I originally posted this in a reply to BCD Clock built using only binary logic.

It was inspired by jryan and LED Clock

Version 1.0 I wrote this to give a graphical rpresentation of the original post.

Version 2.0 I wrote to teach my self Tk Canvas programming and auto resize.

I am sure there is a better way to the the auto resize than the clunky way I am doing it now.

If anyone has suggestions on how to imporove the resize code or any other aspect please post them.

Thanks,
Three

#--------------------------------------------------------------
#    Perl BCD Clock v2.0
#
#    By Three
#
#    Inspired by
#        Think Geek - LED Binary Clock at http://www.thinkgeek.com/cub
+egoodies/lights/59e0/
#        PerlMonks jryan at http://www.perlmonks.com/index.pl?node_id=
+104914
#
#    Origionaly posted at http://www.perlmonks.com/index.pl?node_id=22
+3195
#
#    Updates
#        Replaced radio buttons with direct canvas drawing.
#        Auto resizes according to window size.
#        Replaced clunky set_column sub
#
#--------------------------------------------------------------


#Emulate think geek binary clock in perl tk
use strict;
use warnings;

#Get package in PPM by install Tk
use Tk;

#Size varables
my $diamater;
my $column_size;
my $row_size;
my $column_mid_point;
my $row_mid_point;

#Setup the screen
my $main=MainWindow->new();
$main->MoveToplevelWindow(1,1);
$main->title("BCD Clock");

#Setup Image at default heights
my $canvas = $main->Canvas(-width => 150, -height => 100)->pack(-fill=
+>"both",-expand =>"true");

#Setup screen update timer
my $status_timer = Tk::After->new($main,'1000','repeat',\&process_loop
+);

#Loop for visuals
MainLoop();


#--------------------------------------------------------------
#    Main process loop
#--------------------------------------------------------------
sub process_loop {
    #Main loop of program

    #Clear the canvas
    $canvas->delete('all');

    #Get local time
    my @lt = localtime;

    #Handle single digit problem by left fill 0
    if(length($lt[2]) == 1) { $lt[2] = '0' . $lt[2]; }
    if(length($lt[1]) == 1) { $lt[1] = '0' . $lt[1]; }
    if(length($lt[0]) == 1) { $lt[0] = '0' . $lt[0]; }

    #Calculate positons
    $column_size = $canvas->Width / 6;
    $row_size = $canvas->Height / 4;

    #Compare column size to get the diamater
    if($column_size > $row_size) {
        #If column bigger than row then force row diamater
        $diamater = $row_size;
    } else {
        #If column less than row then force column diamater
        $diamater = $column_size;
    }

    #Reduce the diamater to 6/8 of diamater
    $diamater = ($diamater / 8) * 6;

    #Calculete the midpoints
    $column_mid_point = ($column_size - $diamater) / 2;
    $row_mid_point = ($row_size - $diamater) / 2;

    #Set the radio buttons based on value and position
    set_column(substr($lt[2],0,1), $column_mid_point);
    set_column(substr($lt[2],1,1), $column_size  + $column_mid_point )
+;
    set_column(substr($lt[1],0,1), $column_size * 2  + $column_mid_poi
+nt);
    set_column(substr($lt[1],1,1), $column_size * 3  + $column_mid_poi
+nt);
    set_column(substr($lt[0],0,1), $column_size * 4  + $column_mid_poi
+nt);
    set_column(substr($lt[0],1,1), $column_size * 5  + $column_mid_poi
+nt);
}

#--------------------------------------------------------------
#    Makes the led's based on value and column location
#--------------------------------------------------------------
sub set_column {
    #Ugly cludge to set the radio buttons
    my ($value, $column) = @_;

    #Get ths bits of the value
    my @bits = substr(unpack("B*",$value),-4) =~ /\w/g;

    #Check digit 8 for skip conditons of Hours digit 1, Minute digit 1
+, Seconds digit 1
    if($column != $column_mid_point and $column != $column_size * 2  +
+ $column_mid_point and $column != $column_size * 4  + $column_mid_poi
+nt) {
        #Draw digit 8 based on $bits[0]
        $canvas->createOval($column, $row_mid_point,$column + $diamate
+r, $row_mid_point + $diamater, -fill => $bits[0]?"RED":"BLACK");
    }

    #Check digit 4 for skip conditons of Hours digit 2
    if($column != $column_mid_point) {
        #Draw digit 4 based on $bits[1]
        $canvas->createOval($column, $row_size + $row_mid_point,$colum
+n + $diamater,$row_size + $diamater + $row_mid_point, -fill => $bits[
+1]?"RED":"BLACK");
    }

    #Draw digit 8 based on $bits[2]
    $canvas->createOval($column, $row_size * 2 + $row_mid_point,$colum
+n + $diamater,$row_size * 2 + $diamater + $row_mid_point, -fill => $b
+its[2]?"RED":"BLACK");

    #Draw digit 8 based on $bits[3]
    $canvas->createOval($column, $row_size * 3 + $row_mid_point,$colum
+n + $diamater,$row_size * 3 + $diamater + $row_mid_point, -fill => $b
+its[3]?"RED":"BLACK");
}
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