Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi All, I am trying to re-write an older perl/Tk script that would download an image from a webcam and display it. I would like to use Gtk2 but there is very little example code and documentation available for it ( that I can find - any links would be appreciated ). This bit of code almost does what I need it to minus two things. 1. The image does not update. 2. The image does not scale when the window is resized. One other thing, I would really like to avoid writing the data to a temp file if I can, I would rather download the image data and pipe it directly to Gtk2::Image. Any help would be greatly appreciated !! Thank You ! -T 
#!/usr/bin/perl

$|=1;

use strict;
use Gtk2 '-init';
use MIME::Base64;
use LWP::Simple;

my $load_timeout = undef;
my $CAM_URL      = "http://www.livecam.com.au/livecam1/livecam.jpeg?mu
+=";

my $window = Gtk2::Window->new('toplevel');
$window->signal_connect(delete_event => \&delete_event);
$window->signal_connect(destroy => sub { Gtk2->main_quit; });
$window->set_border_width(10);
my $image = Gtk2::Image->new();
$window->add ($image);
$image->show;
$window->show;
$window->show_all;
do_load();

Gtk2->main;

sub do_load {
   
   getstore($CAM_URL.time(),"/tmp/latest.jpg" );
   $image->set_from_file("/tmp/latest.jpg");

   $image->show;
   $window->show;
   
   unlink("/tmp/latest.jpg");
   
   $load_timeout = Glib::Timeout->add (6500, \&do_load);
   
};

0;

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Replies are listed 'Best First'.
Re: Gtk2::Image Reloading Refreshing and scaling
by zentara (Cardinal) on Aug 09, 2005 at 18:15 UTC
    Automatic scaling of the image when the window is resized is not going to be easy to do.

    To refresh, setup a timer: 

    my $timer = Glib::Timeout->add (100,\&show_refresh);
# timer will run until callback returns false

    [download]

    P.S. You don't need Mime::Base64 for a Gtk2 image.

    To load an image from data try this (I load from a file, but it is converted to scalar data before using) : 

    #!/usr/bin/perl
use strict;
use warnings;
use Gtk2 '-init';

my $mw = Gtk2::Window->new;

my $vp = Gtk2::Viewport->new(undef, undef);
$mw->add($vp);

&load_image;

$mw->signal_connect('destroy', sub { Gtk2->main_quit });
Gtk2->main;

########################################################### 
sub load_image {

 my $file = shift || 'bridget-1.jpg';

my $image_data;
  open (FH,"< $file");
  read( FH, $image_data, -s FH );
  close FH;

 my $loader = Gtk2::Gdk::PixbufLoader->new;
  $loader->write ($image_data);
    $loader->close;
  my $pixbuf = $loader->get_pixbuf;

my $image = Gtk2::Image->new_from_pixbuf ($pixbuf);

my $pb = $image->get_pixbuf;
my ($x, $y) = ($pb->get_width, $pb->get_height);

$vp->add($image);

$mw->set_title("$file ${x}x${y}");
$mw->show_all();

}

    [download]
    If you can deal with a temp file, there is a fantastic image viewer called Gtk2::ImageViwer. It has mouse zoom and pan, but it only loads from a file. 
    #!/usr/bin/perl
######################################################################
+ 
#  Trivial use of Dov Grobgeld's GtkImageViewer. 
######################################################################
+ 

use Gtk2;
use Gtk2::ImageViewer;

Gtk2->init;

$window = Gtk2::Window->new();
$window->signal_connect('destroy', sub { Gtk2->main_quit });

my $file = shift || 'bridget-1.jpg';

$imgv = new_from_file Gtk2::ImageViewer($file);
$window->add($imgv);

$window->show_all();

main Gtk2;

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    I'm not really a human, but I play one on earth. flash japh
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