in reply to Re: Question about embedded Tk::Canvas
in thread Question about embedded Tk::Canvas

This is the problem actually, my $canvas turned to a Tk::Frame in the process. In the simpler script with the same lines of code, even with

 $canvas =  $Matrix->windowCget("$tracknumber,1" , '-window')

it remains a Canvas object.

 bless $canvas, "Tk::Canvas"

doesn't help.

Replies are listed 'Best First'.
Re^3: Question about embedded Tk::Canvas
by kschwab (Vicar) on Nov 20, 2013 at 18:55 UTC
    Seems odd that it would turn into a Frame. I suspect the Canvas is just packed in that frame. Try $widget->children on the Frame, and I bet there's a Canvas there.
[reply]
      Well I have 

       Tk::Canvas=HASH(0x3071f58) 
 Tk::Scrollbar=HASH(0x36db080)
 Tk::Frame=HASH(0x36db608)

      [download]


      but the canvas would rather be a child of the matrix. I check that.
[reply]
[d/l]
      The ancestors from the main window are:

        $tracker_window =  MainWindow->new..
  $TrackBook = $tracker_window->NoteBook..
  $TrackTabs{'Tracks'} = $TrackBook..
  $Matrix = $TrackTabs{'Tracks'}->Scrolled..  
  $canvas = $Mainwin->Scrolled('Canvas')->grid..
  my $real = $canvas->Subwidget("canvas"); # for bindings..
  $CstObj->{'matrix'}->windowConfigure( "$i,1", -window => $canvas )..

      [download]
[reply]
[d/l]
        Right. So your issue is retrieving a reference to the canvas object. The easiest approach would probably be to store a reference to it when you create it. You seem to be creating a module anyway...so perhaps something like: 
        package YourPackage;
use strict;use warnings;
use Tk;
use Tk::Canvas;
sub new {
   my $class = shift;
   my $self = bless {}, $class;
   my $mw = MainWindow->new();
   $self->{'mainwin'}=$mw;
   $self->{'mycanvas'}=$mw->Canvas();
   return $self;
}
sub getcanvas {
   my $self=shift;
   printf "Returning a %s\n",ref($self->{'mycanvas'});
   return $self->{'mycanvas'}
}
package main;
my $YP = YourPackage->new();
my $canvas=$YP->getcanvas();

        [download]
[reply]
[d/l]
      I have also a loop to destroy canvases in refresh, it might be faulty:

        for (my $n = 0; $n < $Maxobj; $n++ ){
    my $canvas =  $CstObj->{'matrix'}->windowDelete("$n,1");
  } ## should delete embedded widgets in canvas track too (I hope).

      [download]
[reply]
[d/l]

In Section Seekers of Perl Wisdom