Re: [clutter] Using Clutter for OSD graphics / transparent window

[Jörn Reder]

Emmanuele Bassi wrote:

> if you provide a patch for the clutter-perl bindings to expose those
> methods (under the Clutter::X11 namespace, for instance) and you verify
> that they work, then I'll consider pushing it upstream.
> 
> [...]
>
> what you need to do is create a small C library that implements a
> subclass of ClutterStage and calls clutter_x11_stage_set_foreign()
> inside the realize() virtual function -- after you chained up to the
> parent implementation.
> 
> then write the Perl bindings using the perl-Glib machinery that
> clutter-perl uses, and use the custom class inside your Perl code.

Thanks for your quick answer!

Since my C/glib knowledge is very limited (subclassing gobject's is 
beyond my scope), I tried quick and dirty binding 
clutter_x11_set_stage_foreign() in ClutterStage.xs to see if this is 
basically working (using Clutter 0.820 from CPAN).

This is the xsub I added:

--snip--

gboolean
clutter_stage_set_foreign_x11_window(ClutterStage *stage, int xwindow)
    CODE:
        RETVAL = clutter_x11_set_stage_foreign(stage, (Window) xwindow);
    OUTPUT:
        RETVAL

--snip--

And used this small script to test:

--snip--

#!/usr/bin/perl

use strict;
use Gtk2 '-init';
use Clutter '-init';
use Glib qw(TRUE FALSE);

main: {
    my $window = Gtk2::Window->new('toplevel');
    $window->set_default_size(800, 400);
    $window->set_decorated(0);

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

    my $colormap = $window->get_screen->get_rgba_colormap;
    $window->set_colormap($colormap) if $colormap;
    $window->show_all;

    my $xid = $window->window->get_xid;
    print "xid=$xid\n";

    my $stage = Clutter::Stage->get_default();
    $stage->set_foreign_x11_window($xid);
    $stage->set_color(Clutter::Color->parse('DarkBlue'));
    $stage->set_opacity(128);

    Gtk2->main;
}

--snip--

That gives me a warning:

  (./osd-test-foreign.pl:20579): ClutterX11-WARNING **: Unable to retrieve the 
new window geometry

and of course no active clutter stage at all ;)

The warning is issued by clutter-stage-x11.c on the check whether all 
conditions of the target X11 window are met:

  if (clutter_x11_untrap_x_errors () ||
      !status ||
      width == 0 || height == 0 ||
      depth != stage_x11->xvisinfo->depth)
    {
      g_warning ("Unable to retrieve the new window geometry");
      return FALSE;
    }

I added some debugging output and found out that the depth condition is
the problem:

  depth                      == 32
  stage_x11->xvisinfo->depth == 24

So my X11 window has an alpha channel while the clutter stage has not.

Is this due to my "quick and dirty" approach or did I hit another 
problem?

Thanks,

Jörn

-- 
sub i($){print$_[0]}*j=*ENV;sub w($){sleep$_[0]}sub _($){i"$p:$c> ",w+01
,$_=$_[0],tr;i-za-h,;a-hi-z ;,i$_,w+01,i"\n"}$|=1;$f='HO';($c=$j{PWD})=~
s+$j{$f."ME"}+~+;$p.="$j{USER}\@".`hostname`;chop$p;_"kl",$c='~',_"zu,".
"-zn,*",_"#,epg,lw,gwc,mfmkcbm,cvsvwev,uiqt,kwvbmvb?",i"$p:$c> ";w+1<<07

pgpOXBI0f1HIj.pgp
Description: PGP signature