#!/usr/bin/perl
use warnings;
use strict;
use Tk;

my $mw =  new MainWindow();
$mw->geometry("600x400+200+200");

#for xscroll, must be packed before midframe to be visible
my $botframe  = $mw->Frame(-bg=>'grey45')
                   ->pack(-fill=>'x',-side=>'bottom');

my $midframe = $mw->Frame(-bg=>'grey45')->pack();
my $midframel = $midframe->Frame(-bg=>'grey45')
                   ->pack(-side=>'left',-expand=>1,-fill=>'y');
my $midframer = $midframe->Frame(-bg=>'grey45')
                   ->pack(-side=>'right');

my $num_channels = 40;

my $canvasp;

my $canvast = $midframer->Canvas(
             -bg =>'pale goldenrod',
             -width=>2400,
             -height=>25,
	     #need to set scrollregion with a bit extra to ensure
	     #endpoint accuracy. See xscrollit sub
	     -scrollregion=>[-10,0,7450,25],
	     -xscrollincrement => 1,
	     )->pack(-side=>'top');

#for canvasp and yscroll
my $midframer1 = $midframer->Frame(-bg=>'grey45')
                   ->pack(-side=>'top');

my $yscroll = $midframer1->Scrollbar( 
       -orient  => 'vertical',
       -command => \&yscrollit,
       -troughcolor =>'grey45',
       -activebackground =>'lightseagreen',
       -background => 'lightseagreen',
       )->pack(-side=>'right',-fill=>'y');

my $canvasxsd = $botframe->Canvas(  #dummy filler
             -bg =>'grey45',
             -width=>75,
             -height=>25,
	     -borderwidth=>0,
	     ) ->pack(-side=>'left');

my $xscroll = $botframe->Scrollbar(
       -orient  => 'horizontal', 
       -command => \&xscrollit ,
       -troughcolor =>'grey45',
       -activebackground =>'lightseagreen',
       -background => 'lightseagreen',
       )->pack(-side=>'right', -fill=>'x',-expand =>1);

print "$xscroll\n";

$canvasp = $midframer1->Canvas(
             -bg =>'lightsteelblue',
             -width=>2400,
             -height=> 50 * $num_channels,
             -scrollregion=>[-10,0,7450,(33 * $num_channels)],
	     -xscrollincrement => 1,
	     -yscrollincrement => 1,
	     -xscrollcommand => [ 'set', $xscroll ],
             -yscrollcommand => [ 'set', $yscroll ],
	     ) ->pack(-side=>'left');#,-fill=>'both');


my $canvasd = $midframel->Canvas( #top of left frame dummy filler
             -bg =>'grey45',
             -width=>75,
             -height=>25,
	     -borderwidth =>0,
	     )->pack(-side=>'top');

my $canvass = $midframel->Canvas(  #left frame canvas
             -bg =>'lightseagreen',
             -width=>75,
             -height=> 50 * $num_channels,
             -scrollregion=>[0,0,75,(33 * $num_channels)],
	     -yscrollincrement => 1,
	     ) ->pack(-side=>'top');

#fill in some sample data to see scrolling action
for( 1 .. 33 * $num_channels){
    $canvass->createText(38, 10 + $_ * 33,
              -text => "C $_" ,
               );

  }

#set up top frame canvas... a timeline
for(0..7200){
       
      if( $_ % 300 == 0){
         my $time =  $_ / 300;
         my $padded = ("0" x (2-length( $time ))).$time;
         $canvast->createLine($_,0,$_,12,-width=> 4,-tags=>['tick'] );
         $canvast->createText($_, 20, -text=> "$padded:00",-tags=>['tick'] );
 
      }elsif( $_ % 150 == 0){
          my $time =  ($_ - 150) / 300;
          my $padded = ("0" x (2-length( $time ))).$time;
         
         $canvast->createLine($_,0,$_,10,-width => 2,-tags=>['tick']);
         $canvast->createText($_, 20, -text=> "$padded:30",-tags=>['tick'] );
      
      }elsif( $_ % 75 == 0){
         $canvast->createLine($_,0,$_,6,-width => 1, -tags=>['tick']);
         
      }      
 
}

#set up main frame canvas
for(0..7200){
   $canvasp->createText($_ * 20, 5 + $_ * 20, 
                        -text=> "Test $_",
			-tags=>['data'] );
}





#---------------------------------------------------------------
MainLoop;
################################################################
#######################################################################
sub xscrollit{
 my $fraction = $_[1];
 $canvast->xviewMoveto($fraction);
 $canvasp->xviewMoveto($fraction);
}
######################################################################
sub yscrollit{
  my $fraction = $_[1];
  $canvass->yviewMoveto($fraction);
  $canvasp->yviewMoveto($fraction);

}
####################################################################