#!/usr/bin/perl -w

use strict;
use Glib qw/TRUE FALSE/;
use Gtk2 '-init';

#add a timer to run each second
Glib::Timeout->add (1000,\&new_screen);

#create a popup window -> this allow us to modify its shape to 
#that of a Gtk::Gdk::Pixmap class.
my $window= Gtk2::Window->new('popup');

	
	#standard packing widget
	my $vbox = Gtk2::VBox->new(FALSE,0);

		my $eventbox = Gtk2::EventBox->new();
		$window->signal_connect('button-press-event' => sub{ exit(0);});
		#create an image containing nothing, this will be set each time 
		#the &new_screen sub runs
		my $img = Gtk2::Image->new_from_pixmap (undef, undef);
		
		$eventbox->add($img);
	
	$vbox->pack_start($eventbox,FALSE,FALSE,0);
	
$window->add($vbox);

$window->set_position('center-always');
#show all BEFORE we add $drawing_area - we do not want to show the drawing
#area, we only use it as a working surface.
$window->show_all();

	#Create a drawing area, and set is big enough to hold the maximum size our 
	#text will ever be.
	my $drawing_area = Gtk2::DrawingArea->new;
	$drawing_area->set_size_request (1600, 1600);
	$vbox->pack_start($drawing_area,FALSE,FALSE,0);
	
	#realize it, since it will not be displayed, but we need to 
	#get hold of the Gdk classes that needs it to be either shown,
	#or realized
	$drawing_area->realize;
		#create a new pango layout for this drawing area 
		#this is a method from the Gtk2::Widged class
		my $pango_layout = $drawing_area->create_pango_layout("");
		#get the defalt colormap (will be needed later on)
		my $colormap = Gtk2::Gdk::Colormap->get_system;
	#initial paint of screen
	&new_screen;

Gtk2->main;
	
sub new_screen {

	#this sub will get a new value of text, and display it on the screen in a shaped 
	#window, to get there needs a few steps

	#get the text that we want to display on the screen.
	my $ts = ret_time();
	
	#Set our pango layout, to reflect the text and format that we want.
	#NOTE We deliberately set the background to a certain color to convert 
	#that color to a alpha channel, that will give us the "clear" background. 
	$pango_layout->set_markup("<span background = '#000000' foreground = '#FF0000' size = '20000' weight ='heavy'>Exact time:\n</span><span background = '#000000' foreground= '#00FF00' size='30000' weight = 'ultralight'><i><u>$ts</u></i></span>");
	
	#Get the size of this layout after the text was set.
	my($pango_w,$pango_h)=$pango_layout->get_pixel_size;
	
	#Now we have the size, we can create a pixmap that will be the
	#'Gtk2::Gdk::Drawable' that we will draw upon
	my $pixmap = Gtk2::Gdk::Pixmap->new ($drawing_area->window,
                                    $pango_w,
                                    $pango_h,
                                    -1);
	#Draw a black block on $pixmap the size of the pango text.
	#This allow us to use newlines in the pango text, just make sure the pango
	#background is also black, as to convert all the black to a alpha channel			    
	$pixmap->draw_rectangle ($drawing_area->style->black_gc,
                        TRUE,
                        0, 0,
                        $pango_w,
                        $pango_h);
			
	#draw the pango layout on the drawable.
	$pixmap->draw_layout($drawing_area->style->white_gc,0,0,$pango_layout);
	
	#create a Gtk2::Gdk::Pixbuf that we will use to grab the pango text from the
	#drawable (Gtk2::Gdk::Pixmap which is a Gtk2::Gdk::Drawable) 
	my $pixbuf = Gtk2::Gdk::Pixbuf->new ('rgb', TRUE, 8, $pango_w, $pango_h);
	
	#here we get create a pixbuff from the drawable, this is where we need the colormap
	$pixbuf->get_from_drawable ($pixmap, $colormap, 0, 0, 0,0, $pango_w, $pango_h);
		
		#Remove the background (we use the color we specified as the pango text's
		#background
		$pixbuf = $pixbuf->add_alpha (TRUE, 0, 0 , 0);
		
		#create a pixmap and mask from the Gtk2::Gdk::Pixbuf
		my ($pm, $m) = $pixbuf->render_pixmap_and_mask (255);
	#shrink our window to make sure the mask and pixmap will be on the same spot.
	$window->resize(4,4);
	#replace the old $img with the new pixmap and mask
	$img->set_from_pixmap ($pm, $m);
	
	#shape our window accordingly
  	$window->shape_combine_mask ($m, 0, 0);
  	
	return TRUE;
	
}


sub ret_time {
	#sub to return a string containing the time
my($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst)= localtime(time+3600);
  	my @lst =("Sun","Mon","Tue","Wed","Thu","Fri","Sat");
  	my $thisday =$lst[$wday];
  	$year = $year + 1900;
  
  	($sec =~ m/\d{2}/)||($sec = "0".$sec);
  	($min =~ m/\d{2}/)||($min = "0".$min);
  	($hour =~ m/\d{2}/)||($hour = "0".$hour);
  	$mon = $mon +1;
  	#print("\n");
  	my $ts = "$thisday $mday/$mon/$year $hour:$min:$sec";
	
	return $ts;
}