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

Hi all,

I'm currently adding a splashscreen to my application. I'm using Tk::Splashscreen for that (but it is possible to switch)
I've created a nice png with some transparency and blurring on the sides, to create a nice effect.

The problem is this:
I expected to see my desktop background through the transparent parts of my image, but instead, I see the background of the canvas that I put the image on.

This is my code: 
my $splash = $mw->Splashscreen(-milliseconds => 3000);
my $canvas = $splash->Canvas(-width => 420,
                             -height => 300)->pack;
$canvas->createImage(0, 0,
                     -anchor => 'nw',
                     -image => $mw->Photo(-file => 'gfx/splash.png'));
$mw->withdraw;
$splash->Splash();

[download]
I've also tried to put the image on a label instead of on a canvas: 
$splash->Label(-image => $mw->Photo(-file => 'gfx/splash.png'));

[download]
But the result is the same. I've read in Perl-Tk's docs, and I've seen here and there that backgrounds can be set to be transparent by setting the -background to undef. But that doesn't seem to help me too.

Do any of you monks have any idea of how I can make the background of my image-container transparent too? So that I see whatever is behind the splashscreen through the transparent parts of my image?
Thanks! ldx

Replies are listed 'Best First'.
Re: Splashscreen with transparency
by zentara (Cardinal) on Oct 09, 2008 at 12:05 UTC
[reply]
      Thanks zentara,

      But is there really no way to do it with Perl::Tk?
      I'm not very eager to do my entire UI over in Gtk :)

      Regards,
      ldx
[reply]
        No, Tk dosn't have transparency yet. Tk::Zinc will allow window shaping (round windows, etc), but not transparency. You can run Tk and Gtk2 simultaneously in the same script, with a master loop and a timer for the second loop. So you could pop your splashscreen, then remove the Gtk2 and run your Tk. Here is a simple example, just stop the timer after the splashscreen is closed, and undef Gtk2 stuff. 
        #!/usr/bin/perl -w
use strict;
use Gtk2;
use Tk;

my $mw = MainWindow->new(-title=>'Tk Window');

Gtk2->init;
my $window = Gtk2::Window->new('toplevel');
$window->set_title('Gtk2 Window');
my $glabel = Gtk2::Label->new("This is a  Gtk2 Label");
$window->add($glabel);
$window->show_all;

my $tktimer = $mw->repeat(10, sub{      
   Gtk2->main_iteration while Gtk2->events_pending;
   #manually pump the Gtk2 eventloop as a slave
  });

my $tktimer1 = $mw->after(1000, sub{      
   $window->destroy;
   Gtk2->main_iteration while Gtk2->events_pending;
   $tktimer->cancel;
  });


$mw->Button(-text=>'     Quit     ',
       -command => sub{exit}
        )->pack();

MainLoop;

        [download]
        I'm not really a human, but I play one on earth Remember How Lucky You Are
[reply]
[d/l]
Re: Splashscreen with transparency
by Anonymous Monk on Oct 09, 2008 at 07:15 UTC
    Its not supported by Tk
[reply]

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