Re^2: How to destroy and re-create bound widgets

[Phinix]

I did try createWindow... I'm still learning so I've been just experimenting and doing research trying to get the syntax right. Perhaps though you could explain why doing this:

my $canvaswindow = $canvas->createWindow(0,0, -window => $widget);

$canvaswindow->Tk::bind('<Button-1>' => sub { &dostuff0 });

...gives me an error saying: "Global symbol "$canvaswindow" requires explicit package name at line 3."

I have created $widget before attempting this, of various types. Is it not possible to create custom event binds on canvas objects? If so, that is why I do not use createWindow. If it is possible I would love to know how.

EDIT: I was able to get things working after I realized that the createWindow method isn't so much creating a new object that gets a reference but rather more like saying "put me here" to a previously created object template.

So, the above instead becomes:

$canvas->createWindow(0,0, -window => $widget);

$widget->Tk::bind('<Button-1>' => sub { &dostuff0 });

I'll post a full working example in a bit once I finish the translation. Thanks for all the helpful pointers and syntax examples though!

[zentara]

It sounds like you, as a beginner, my want to reconsider your design. The first thing I have to say, is why do you need the overlapping secondary sub-canvases? If you can make something on your sub-canvas, you can do the same thing on the underlying canvas. You can still put a background image on the main canvas, then instead of overlaying other canvases, why not create rectangular regions on the base canvas? In any event, look at this example:

#!/usr/bin/perl
use warnings;
use strict;
use Tk;

my $mw = new MainWindow;

my $main = $mw -> Scrolled("Canvas",-scrollbars=>'e')-> 
          pack(-side =>'left', -fill => 'both', -expand => 1);

my $canvas = $main->Subwidget("canvas");

Tk::bind($canvas, '<MouseWheel>', [ sub {$canvas->yview('scroll',
    -($_[1] / 120) * 3,'units')}, Ev('D')]); 

my $see = "\nHaaa, See that and scroll!";

my $info = $main->createText(180, 15, -text => "$see", 
                    -font => 'Arial 11 bold' , -fill => 'red');

$main->configure(-scrollregion => [0,0,2000 , 2000]);

my $canvas_cube = $main->Canvas(-width => 45, -height => 45, 
                                          -background => 'green');

my $canvasWindow = $main->createWindow(75,75, -window => $canvas_cube)
+;

Tk::bind( $canvas_cube,  '<Enter>' => sub { print "Enter\n"; });
Tk::bind( $canvas_cube,  '<Leave>' => sub { print "Leave\n"; });

Tk::bind( $canvas_cube,  '<Button-1>' => sub { print "1\n"; });

$canvas->focus;

MainLoop;

[zentara]

Also see embedding xterm into a Tk app. If you are determined to use embeded Canvases, you could use this technique, to hide show them. Tk is somwhat limited and you need to cover the createWindow with another properly colored rectangle.

Tk::Zinc can actually hide or show the window. See the second example in Re: Window with background image and transparent listbox . You could put a second Zinc canvas in there, instead of an xterm.