Re: PixbufWidget.pm

[Paolo Molaro <lupus ximian com>]

On 01/27/01 Jens Luedicke wrote:
> I wasted my time to hack this little module. 
> It's based on test.pl in GdkPixbuf/samples 
>
> I hope someone likes it and/or uses it... 

Just a few quick comments...

> sub new {
>       shift;
>       my ($file) = @_;
>
>       die "Usage: PixbufWidget->new(\"file\")\;"
>               if($file eq "");

You should check with a simple 'if $file', since it can be undef and
spew warnings.

>       my $box = new Gtk::VBox(0,0);
>       $box->set_app_paintable(1);

As the base widget for drawing Gtk::DrawingArea fits way better
and doesn't need the paintavle hack.

>       my $pixbuf = new_from_file Gtk::Gdk::Pixbuf($file);
>
>       $box->signal_connect('expose_event', sub {
>               $pixbuf->render_to_drawable_alpha(
>                       $box->window,
>                       0, 0, 0, 0,
>                       $pixbuf->get_width(), $pixbuf->get_height(),
>                       0, 50, 0, 0, 0
>               );

You should really draw only the exposed area:
$darea->signal_connect('expose_event', sub {
        my ($w, $e) = @_;
        my ($x, $y, $wi, $h) = @{$e->{'area'}};
        $w->window->draw_pixmap($gc, $bp, $x, $y, $x, $y, $wi, $h);
        return 0;
});

where $bp is a backing pixmap you create with $pixbuf->render_to_drawable().
Note that this example doesan't handle the alpha channel.
You should be able to do it even without the backing pixmap, with the
right params to render_to_drawable_alpha().

The GdkPixbuf/sample/test.pl code should really be rewritten to
match my own comments, I agree:-)

lupus

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