Re: Display Portions of an Image

[Eric Andreychek <eric openthought net>]

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Howdy,

> if the GtkImage you are using is set to use a GdkPixbuf for internal 
> storage, you should be able to ask the GtkImage for the pixbuf it uses, 
> and draw onto that.  then you have to figure out how to get the widget 
> to redraw itself (used to be gtk_widget_queue_draw, but i'm not sure 

I'm almost there!  Using Gavin's explanation of copy_area, and Scott's
suggestion of writing on the images existing pixbuf, it does work.  Sort of.

I'm using this code:

    if ( exists $self->{icon} ) {
        $self->{icon}->set_from_pixbuf($image_to_display);
    }
    else {
        $self->{icon} = Gtk2::Image->new_from_pixbuf($display_image);
        $self->{widget}->add($self->{icon});  # Widget is a button
    }
    $self->{widget}->queue_draw;

I've found that the image, using the above code, will not redraw itself.  That
was incredibly frustrating, until I decided to output some debug information to
try and figure out the problem.  As soon as I did so, it worked fine.

That is, if I simply add to the bottom of the above code:

  print "Something is fishy";

The image happily redraws itself.

Does anyone have any suggestions on a better way to get this thing to redraw,
without needing to output anything?  FWIW, outputting text only fixes the
problem when I output to STDOUT.  Using warn to print to STDERR will not fix
it, the image doesn't get redrawn in that case.

Any thoughts would be great, thanks!
  -Eric


- -- 
 Eric Andreychek              | Lucy: "What happens if you practice the
 Eric Conspiracy Secret Labs  |  piano for 20 years and then end up not
 eric openthought net         |  being rich and famous?"
 http://openthought.net       | Schroeder: "The joy is in the playing."
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