#!/usr/bin/perl -w
use strict;
use warnings;
use Goo::Canvas;
use Gtk2 '-init';
use Glib qw(TRUE FALSE);
use Gtk2::Gdk::Keysyms;

my $scale = 1;

my $window = Gtk2::Window->new('toplevel');
$window->signal_connect('delete_event' => sub { Gtk2->main_quit; });
$window->set_size_request(800, 600);

my $swin = Gtk2::ScrolledWindow->new;
$swin->set_shadow_type('in');
$window->add($swin);

my ($cwidth,$cheight)= (1200,1200);
my $canvas = Goo::Canvas->new();
$canvas->set_size_request(800, 650);
$canvas->set_bounds(0, 0, $cwidth, $cheight);
my $black = Gtk2::Gdk::Color->new (0x0000,0x0000,0x0000);
my $white = Gtk2::Gdk::Color->new (0xFFFF,0xFFFF,0xFFFF);
$canvas->modify_base('normal',$white );
$swin->add($canvas);

my $root = $canvas->get_root_item();

my ($margin_x,$margin_y) = (100,100); 

my $g = Goo::Canvas::Group->new($root); 
$g->scale(1,-1); #reverse direction of y axis, so graphing will be normal cartesian
$g->translate(0 + $margin_x, -1200 + $margin_y); #notice translations are reversed
$canvas->scroll_to(0,$cheight);

# add a background rect filling $g, so button press will be detected
# otherwise $g will be invisible to button-press-event
my $rect = Goo::Canvas::Rect->new(
    $g, 0, 0, $cwidth,$cheight,
    'line-width' => 1,
    'stroke-color' => 'white', #invisible on white bg
    'fill-color' => 'white',   # must be filled for mouse event sensitivity
    );

# some key help
 my $markup = "<span font_family ='Arial '
               foreground = '#000000'  
               size = '12000' 
               weight = 'ultralight'> Keys: 'Z' zoom in,   'z' zoom out,   's' save a PDF </span>";

 my $text = Goo::Canvas::Text->new(
             $g, 
             $markup,
             -80 , 80 , -1, 
             'w',
             'use markup' => 1,
            );
             
            $text->scale(1,-1);




$g->signal_connect('button-press-event',
                      \&on_g_button_press);

$canvas->signal_connect_after('key_press_event', \&on_key_press);
$canvas->can_focus(TRUE);
$canvas->grab_focus($root);

&set_axis();
&plot();

$window->show_all();

Gtk2->main;

sub set_axis{

# x axis
my $xline = Goo::Canvas::Polyline->new(
         $g, TRUE,
         [0,0,900,0], 
         'stroke-color' => 'black',
        'line-width' => 3,
    );

#label
      my $markup = "<span font_family ='Arial '
               foreground = '#000000'  
               size = '18000' 
               weight = 'bold'> X axis Label </span>";

           my $text = Goo::Canvas::Text->new(
             $g, 
             $markup,
             450 , 80 , -1, 
             'center',
             'use markup' => 1,
            );
             
            $text->scale(1,-1);



for my $x (0..900){
       
       if ($x % 100 == 0){
          my $xtick = Goo::Canvas::Polyline->new(
             $g, TRUE,
             [$x,0,$x,-25], 
             'stroke-color' => 'black',
             'line-width' => 3,
        );

          $markup = "<span font_family ='Arial '
               foreground = '#0000ff'  
               size = '10000' 
               weight = 'light'> $x </span>";

            $text = Goo::Canvas::Text->new(
             $g, 
             $markup,
             $x-1 , 10 , 1, 
             'north-east',
             'use markup' => 1,
             'wrap' => 'char');
             
            $text->scale(1,-1);


        
          }elsif ($x % 10 == 0){
         
           my $xtick = Goo::Canvas::Polyline->new(
               $g, TRUE,
               [$x,0,$x,-15], 
               'stroke-color' => 'red',
               'line-width' => 1,
            );
       
         my $markup = "<span font_family ='Arial '
               foreground = '#ff0000'  
               size = '8000' 
               weight = 'ultralight'> $x </span>";

           my $text = Goo::Canvas::Text->new(
             $g, 
             $markup,
             $x-1 , 6 , 1, 
             'north-east',
             'use markup' => 1,
             'wrap' => 'char');
             
            $text->scale(1,-1);
            
        }
  }

# y axis
my $yline = Goo::Canvas::Polyline->new(
         $g, TRUE,
         [0,0,0,900], 
         'stroke-color' => 'black',
        'line-width' => 3,
    );


#label
       $markup = "<span font_family ='Arial '
               foreground = '#000000'  
               size = '18000' 
               weight = 'bold'> Y axis Label </span>";

           $text = Goo::Canvas::Text->new(
             $g, 
             $markup,
             -70 ,-450 , -1, 
             'center',
             'use markup' => 1,
             );
             
            $text->scale(1,-1);
            $text->rotate(-90,-70,-450);


for my $y (0..900){
       
       if ($y % 100 == 0){
          my $ytick = Goo::Canvas::Polyline->new(
             $g, TRUE,
             [0,$y,-25,$y], 
             'stroke-color' => 'black',
             'line-width' => 3,
        );

          $markup = "<span font_family ='Arial '
               foreground = '#0000ff'  
               size = '10000' 
               weight = 'light'> $y </span>";

            $text = Goo::Canvas::Text->new(
             $g, 
             $markup,
             -25 , -$y -8 , -1, 
             'north-east',
             'use markup' => 1,
             );
             
            $text->scale(1,-1);


        
          }elsif ($y % 10 == 0){
         
           my $ytick = Goo::Canvas::Polyline->new(
               $g, TRUE,
               [0,$y,-15,$y], 
               'stroke-color' => 'red',
               'line-width' => 1,
            );
       
         my $markup = "<span font_family ='Arial '
               foreground = '#ff0000'  
               size = '8000' 
               weight = 'ultralight'> $y </span>";

           my $text = Goo::Canvas::Text->new(
             $g, 
             $markup,
             -16 , -$y - 6 , -1, 
             'north-east',
             'use markup' => 1,
             );
             
            $text->scale(1,-1);
            
        }
  }


}

sub plot{

  my @points;
  
  for my $x (0..900){

      push @points,$x, 300 + 100*sin( $x /5);
   
   }

   my $poly = Goo::Canvas::Polyline->new(
        $g, FALSE,
         \@points, 
        'stroke-color' => 'green',
        'line-width' => 2,
       );
}

sub on_g_button_press {
     #print "@_\n";
     my ( $group, $widget, $event ) = @_;
     print $widget ,' ',$event->type, '  ','button',' ',$event->button,"\n";
     my ($x,$y) = ($event->x,$event->y);
      print "$x  $y\n";
    return 0;
}

sub on_key_press {
    # print "@_\n";
     my ( $canvas, $event ) = @_;
    # print $event->type,"\n";

    if ( $event->keyval == $Gtk2::Gdk::Keysyms{Z} ) {
        $scale += .1;
        $canvas->set_scale($scale);
        $canvas->scroll_to(0,$cheight);
    }

    if ( $event->keyval == $Gtk2::Gdk::Keysyms{z} ) {
        $scale -= .1;
        $canvas->set_scale($scale);
        $canvas->set_scale($scale);
        $canvas->scroll_to(0,$cheight);
    }

    if ( $event->keyval == $Gtk2::Gdk::Keysyms{s} ) {
        write_pdf($canvas);
    }

#    print "key was ", chr( $event->keyval ), "\n";

    return 0;
}


sub write_pdf {
    #print "@_\n";
    my $canvas = shift;
    print "Write PDF...\n";

    my $scale = $canvas->get_scale;
    print "scale->$scale\n"; 
    
    my $surface = Cairo::PdfSurface->create("$0-$scale.pdf", 
                    $scale*$cwidth, $scale*$cheight);
    
    my $cr = Cairo::Context->create($surface);

    # needed to save scaled version
    $cr->scale($scale, $scale);

    $canvas->render($cr, undef, 1);
    $cr->show_page;
    print "done\n";
    return TRUE;
}
__END__