KuntalBhusan has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks, I want to create two Tk::Abstract canvases. One (lets call it Canvas1) would display a huge graph (consisting of nodes and edges) and other small canvas (lets call it Canvas2) which will contain a smaller view of the same graph (using the ViewAll function of AbstractCanvas). I want to use some simple interactions like a small rectangle in Canvas2 to scroll and view the big network of Canvas1.

Under the module description part of Tk::Abstract Canvas, I can find the topic "updating a second AbstractCanvas which is displaying the view region of the first AbstractCanvas" and a code example too, but I cannot figure out how to implement the same.

My code is something like this : 

$abstractcanvas1  = $SomeFrame->Scrolled(qw/
       AbstractCanvas -bg white
       -confine 1
       -scrollbars se/,
       )->pack(-fill   => 'both',-expand => 1);


$can = $abstractcanvas2->Subwidget('scrolled');



$abstractcanvas2  = $SomeFrame->Scrolled(qw/
       AbstractCanvas -bg white
       -confine 1
       -scrollbars se/,
       )->pack(-fill   => 'both',-expand => 1);


$can = $abstractcanvas2->Subwidget('scrolled');


## code to display the network in $Canvas1

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Where should I now use this code part as described in the Module help of Tk::AbstractCanvas 
$abstractcanvas2  = $f_Left->Scrolled(qw/
       AbstractCanvas -bg white
       -confine 1
       -scrollbars se/,
       )->pack(-fill   => 'both',-expand => 1);

$can_1 = $abstractcanvas2->Subwidget('scrolled');



$abstractcanvas1->configure(-changeView => [\&changeView, $abstractcan
+vas2]);


  # viewAll if AbstractCanvas2 widget is resized.


  $abstractcanvas2->CanvasBind('<Configure>' => sub {$abstractcanvas2-
+>viewAll});
  {
    my $viewBox;
    sub changeView {
      my ($canvas2, @coords) = @_;
      $canvas2->delete($viewBox) if $viewBox;
      $viewBox = $canvas2->createRectangle(@coords, -outline => 'orang
+e');
    }
  }

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And how to do it ?? Thanks, Kuntal

Replies are listed 'Best First'.
Re: How to control a Tk::AbstractCanvas with a second one
by Anonymous Monk on Nov 29, 2012 at 09:33 UTC

    My code is something like this ...

    Why don't you start with ex/chvw.pl, it shows this exactly?

    Ctrl+MouseRight zooms the first canvas, and the second canvas

    Ctrl+MouseMiddle moves the first canvas, and the second canvas

    LeftMouse rotates the first canvas, doesn't do much for the second :)

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[reply]

      And here it is, busywork 

      #!/usr/bin/perl --
use strict; use warnings;
use Tk;
use Tk::AbstractCanvas;
{
    my $mwin = my $mw = tkinit;
    my $acnv = $mwin->AbstractCanvas()->pack(-expand => 1, -fill => 'b
+oth');
    $acnv->controlNav(1); # advanced CtrlKey+MouseDrag Navigation
    $acnv->rectToPoly(1);
    $acnv->ovalToPoly(1);
    my $rect   = $acnv->createRectangle( 7,  8, 24, 23, -fill  =>   'r
+ed');
    my $oval   = $acnv->createOval(     23, 24, 32, 27, -fill  => 'gre
+en');
    my $line   = $acnv->createLine(      0,  1, 31, 32, -fill  =>  'bl
+ue',
                                                        -arrow =>  'la
+st');
    my $labl   = $mwin->Label(-text => 'Hello AbstractCanvas! =)');
    my $wind   = $acnv->createWindow(15, 16, -window => $labl);
    $acnv->CanvasBind('<x>' => \&exit);
    $acnv->CanvasFocus();
    $acnv->viewAll();
    
    my $c2 = $mwin->Canvas(
        -background => 'black',
#~         -width  => 100,
#~         -height => 100,
#~         -width  => 20,
#~         -height => 20,
        -width  => 30,
        -height => 30,
    );
    $c2->createOval(0, 0, 5, 5, -fill => 'white',-tags => ['shabba'] )
+;
    $mw->bind( $c2, '<ButtonPress-1>' => [ \&shabba , $acnv ]);
    $c2->place( qw/ -x 10 -y 10 / );
}

MainLoop;
sub shabba {
    my( $c2, $acnv ) = @_;
#~         my $c2 = $Tk::event->W; 
    my $x = $Tk::event->x;
    my $y = $Tk::event->y;
#~ use Data::Dump;
#~ dd [ $c2->configure ], [ $c2->itemconfigure( 'shabba' )] ;
    $c2->coords( 'shabba', $x, $y , $x+5, $y+5); # size is 5
    my $width  = $c2->cget('-width');
    my $height = $c2->cget('-height');
    my $xview  = $x / $width;
    my $yview  = $y / $height;
    $acnv->xviewMoveto( $xview );
    $acnv->yviewMoveto( $yview );
    
}

      [download]

      See also Tk::Zinc / http://web.archive.org/web/20061020033841/http://www.tkzinc.org/

[reply]
[d/l]
      Thanks for the reply....but I actually wanted the reverse...I want to move the orange rectangle in the second canvas (which will have a scaled down view of the original) and the first canvas display should move appropriately...is it possible ?
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