Re: One more Gnome2::Canvas question -- item->grab() $event_mask

[Mike Mayer <mikem circuitfarm com>]

partly solved: I was using the gentoo ebuilds, which are older versions.
I installed gnome2-canvas 0.91 and glib 1.021 and it now accepts the
mask values.

However, when I ungrab an item the cursor and mask remain set to the
state the item->grab() put them in.

I'm trying to drag groups around a canvas. I'm following the examples as
closely as I can. Here is the event callback that I am using. Everything
works except that when I get the button-release event and ungrab, the
cursor stays a fleur and nothing can get a button-press event:

sub GroupEvent {

    my $item = shift;
    my $event = shift;
    my $data = shift;

    my ($x1, $y1, $x2, $y2) = $item->get_bounds();
    my $type = $event->type();
    my $itemY = $y1;
    my $cursorY = $event->y();

    print "Group event...type $type\n";

    if (defined($layerRef{$item})) {
        my $layer = $layerRef{$item};
        my $layerName = $layer->getName();
        my $layerType = $layer->getType();
    }

    if ($type eq "button-press") {
        my $button = $event->button();
        if ($button == 1) {
            print("Button1 at $itemY\n");
            $y = $cursorY;
            $startY = $cursorY;
            $item->grab([qw/pointer-motion-mask button-release-mask/],
                        Gtk2::Gdk::Cursor->new('fleur'),
                        $event->time());
            $possibleDragging = 1;
            $item->raise_to_top();
        }
    }
    elsif ($type eq "2button-press") {
    }
    elsif ($type eq "button-release") {
        print "startY: $startY, itemY: $itemY\n";
        if ($dragging) {
            my $layerLoc = round($itemY / $GRID_SPACING);
            my $layerY = $layerLoc * $GRID_SPACING;
            my $moveY = $layerY - $itemY;
            print "dropped on layer $layerLoc ($layerY), moving
$moveY\n";
            $item->move(0, $moveY);
            $item->ungrab($event-time());
            $dragging = 0;
        }
        else {
            print "Clicked on group\n";
            $possibleDragging = 0;
        }
    }
    elsif ($type eq "motion-notify") {
        if ($possibleDragging) {
            if (abs($startY - $itemY) > $CLICK_MARGIN) {
                $dragging = 1;
                $possibleDragging = 0;
            }
        }
        if ($dragging) {
            my $newY = $cursorY;
            # only move in y to keep column in alignment
            $item->move(0, $newY - $y);
            $y = $cursorY;
        }
    }
    elsif ($type eq "enter-notify") {
    }
    elsif ($type eq "leave-notify") {
    }
    return FALSE;
}


 

-- 
=============================================================================
Mike Mayer                                      Phone: (608) 523-1960
Circuitfarm, Inc.                               Cell:  (608) 575-2732
mikem circuitfarm com