Re: Working with images

[Daniel Kasak <dkasak nusconsulting com au>]

muppet wrote:

> On Aug 19, 2004, at 8:39 PM, Daniel Kasak wrote:
>
> > >                 $fade_image->composite->(
> you don't want that extra -> there.
>
>                     $fade_image->composite(

Ah. Yes, now I feel stupid. Man, I looked at that line for 20 minutes 
without spotting that.

> > At this point, $splash_frame certainly containts a Gtk2::Gdk::Pixbuf. 
> > The only bit I'm unsure of is the Gtk2::Gdk::InterpType bit, for 
> > which I used 'nearest'.
>
> if you're using scale factors of 1, then the interptype is rather 
> uninteresting.
??? The scale factor of 1 is the only setting that gives me the image 
scaled at the right size. Other settings make it ... well ... too big.

I've changed a few other things around. If I used a 'blank' window from 
a glade file and added the DrawingArea to it, the 
splash_screen_expose_callback sub wasn't being called. Don't know why. 
Maybe it was just another of my mistakes. Anyway, not matter. I've 
currently got:

-----

sub load_splash_screen {
  
   $splash_screen = Gtk2::Window->new;
   $splash_screen->set_size_request (400, 300);
   $splash_screen->set_title ("Pixbufs");
   $splash_screen->set_resizable (0);
  
   $splash_screen->signal_connect (destroy => sub 
{$splash_screen=undef; 1});
   $splash_screen->signal_connect (destroy => \&splash_screen_cleanup);
  
   $splash_frame = Gtk2::Gdk::Pixbuf->new ('rgb', 'FALSE', 8, 400, 300);
   $background_image = 
Gtk2::Gdk::Pixbuf->new_from_file("$currentdir/sales/background.jpg");
   $fade_image = 
Gtk2::Gdk::Pixbuf->new_from_file("$currentdir/sales/nus_consulting_group.png");
  
   $splash_screen->signal_connect (destroy => sub 
{$splash_screen=undef; 1});
   $splash_screen->signal_connect (destroy => \&splash_screen_cleanup);
  
   $splash_drawing_area = Gtk2::DrawingArea->new;
   $splash_drawing_area->signal_connect (expose_event => 
\&splash_screen_expose_callback);
   $splash_screen->add($splash_drawing_area);
  
   $splash_screen->show_all;
  
   $splash_timeout = Glib::Timeout->add (50, \&splash_timeout);
   $splash_counter = 1;
  
}

sub splash_screen_cleanup {
  
   Glib::Source->remove ($splash_timeout);
   $splash_timeout = 0;
  
}

sub splash_timeout {
  
   if ($splash_counter > 126) {
      
       $splash_screen->destroy;
      
   } else {
      
       $background_image->copy_area(
                                       0, 0,
                                       400, 300,
                                       $splash_frame,
                                       0, 0
                                   );
      
       print "Counter: $splash_counter\n";
      
       $fade_image->composite(
                                       $splash_frame,
                                       0, 0,
                                       400, 300,
                                       50, 100,
                                       1, 1,
                                       'nearest',
                                       $splash_counter * 2
                             );
      
       $splash_counter++;
      
       $splash_drawing_area->queue_draw;
       return 1;
      
   }
  
}

sub splash_screen_expose_callback {
  
   my ($widget, $event) = @_;
  
   my $drawable = $widget->window;
  
   $drawable->draw_pixbuf(
                           $widget->style->black_gc,
                           $splash_frame,
                           $event->area->x, $event->area->y,
                           $event->area->x, $event->area->y,
                           $event->area->width, $event->area->height,
                           'normal',
                           $event->area->x, $event->area->y
                         );
  
   return 1;
  
}

-----

This runs and at least produces 'something'.
There are 2 remaining problems.

Problem 1:
The first one is probably just my lack of understanding. What I *want* 
is to have the background image remain 'static' in the background, ie 
always completely visible. Then I want the $fade_image to fade in.

What I'm getting is *both* images fading in, and towards the end the 
$fade_image masks out the background completely. This last bit is fine - 
I understand that if I set the overall_alpha value to 255 it will mask 
everything else. But why does the background image fade *in*? I thought 
it would be completely visible from the start, and then fade out while 
the other image's overall_alpha caused it to be masked out.

Problem 2:
This one is a little worse. I'm getting strange 'streaks' - rendering 
bugs - in the image. The best way to describe it is with a screenshot or 
two.

Half-way through the loop:
http://www.nusconsulting.com.au/internal/render_01.jpg
A little further through the loop:
http://www.nusconsulting.com.au/internal/render_02.jpg

See the horizontal and vertical lines streaking out from the logo in the 
middle?
What are they?
I've tried using all the different interptypes. They all produce the 
same thing, but slower.

Other than that, it's working :)

--
Daniel Kasak
IT Developer
NUS Consulting Group
Level 5, 77 Pacific Highway
North Sydney, NSW, Australia 2060
T: (+61) 2 9922-7676 / F: (+61) 2 9922 7989
email: dkasak nusconsulting com au
website: http://www.nusconsulting.com.au

Title: CanIt Vote for ID 87474

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