Here is a basic example from the Perl/Gtk2 maillist that works thru all the haze. There are some fine points to mention, especially the expose_event callback. The DrawingArea is NOT persistent, so everytime it is exposed you need to refresh the pixels. See Drawing with Perl/Gtk2 for some more ideas.

#!/usr/bin/perl
use warnings;
use strict;
use Cairo;
use Gtk2 '-init';
use Glib qw(TRUE FALSE);

my ( $width, $height ) = ( 400, 200 );
my $window = Gtk2::Window->new( 'toplevel' );

my $surface  = create_image();

$window->signal_connect( 'delete_event' => sub { Gtk2->main_quit; } );


my $drawable = Gtk2::DrawingArea->new;

$drawable->size( $width, $height );
$drawable->signal_connect(
   'expose_event' => \&on_expose_event,
   $surface
);

$window->add( $drawable );
$window->show_all;
Gtk2->main;

sub create_image {

   my $surface = Cairo::ImageSurface->create( 'argb32', $width, $heigh
+t );
   my $cr = Cairo::Context->create( $surface );

# make a background rectangle filled white
    $cr->rectangle( 0, 0, 400, 400 );
    $cr->set_source_rgb( 1, 1, 1 );
    $cr->fill;

   $cr->set_source_rgb( 0, 0, 0 );
   $cr->select_font_face( "Sans", 'normal', 'normal' );
   $cr->set_font_size( 40.0 );
   $cr->move_to( 10, 50 );
   $cr->show_text( "Disziplin ist Macht." );

   $cr->fill;
   $cr->show_page;
   
   return $surface;
}

sub on_expose_event {
   my ( $widget, $event, $surface ) = @_;
   my $cr = Gtk2::Gdk::Cairo::Context->create( $widget->window );
   $cr->set_source_surface( $surface, 0, 0 );
   $cr->paint;
  
#   $surface->write_to_png ("$0.png");

   $cr->show_page;


# primitive attempts to get png stream

#  my $output='';
#  $surface->write_to_png_stream (sub {
#   my ($closure, $data) = @_;
#   $output .= $data;
#   });

# my $loader = Gtk2::Gdk::PixbufLoader->new;
# $loader->write($output);
# $loader->close;
# my $pixbuf = $loader->get_pixbuf;
#my $img_orig = Gtk2::Image->new_from_pixbuf($pixbuf);    

#A minor style note.  Instead of above:
#You can do this:  #Torsten Schoenfield

my $loader = Gtk2::Gdk::PixbufLoader->new;
  $surface->write_to_png_stream (sub {
    my ($closure, $data) = @_;
    $loader->write($data);
  });
$loader->close;
my $pixbuf = $loader->get_pixbuf;


print $pixbuf->get_bits_per_sample(),"\n";
print $pixbuf->get_colorspace(),"\n";

$pixbuf->save ("$0.png", 'png');
$pixbuf->save ("$0.jpg", 'jpeg', quality => 100);
  
   return FALSE;
}

__END__

>
> The perl API is pretty much the same; $imagesurface->get_data() retu
+rns
> you a scalar holding the image data.  If you ensure that the cairo i
+mage
> surface is created in cairo's RGB24 format, you can use the data
> directly with Gtk2::Gdk::Pixbuf like this:
>
>
>      my $width = $surface->get_width;
>      my $height = $surface->get_height;
>      my $stride = $surface->get_stride;
>      my $data = $surface->get_data;
>
>      my $pixbuf = Gtk2::Gdk::Pixbuf->new_from_data ($data, 'rgb', FA
+LSE,
> 8, $wudth, $height, $stride);
>
>      my $image = Gtk2::Image->new_from_pixbuf ($pixbuf);
>
Also I try this way, but it seems weird, the window is black.
the document of  gdk_pixbuf_new_from_data says "only RGB images with 8
bits per sample are supported", is it the reason?
Any way, thanks again for the help.


--
Best Regards,
Ye Wenbin
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