Hello! Finally had a question I couldn't figure out or find on my own, so I request the wisdom of the keepers of Perl knowledge. I have a program which uses Tk::canvas, and I am trying to gather the coordinates of a mouse click on the canvas. What I would like to know is why the first bit of code works, where as numerous attempts at code similar to the second bit does not.

Works: 
$canvas{'ref'}->CanvasBind("<1>", [ \&print_xy, Ev('x'), Ev('y') ]); 

sub print_xy{
   my ($canv, $x, $y) = @_;
   print "(x,y) = ", $canv->canvasx($x), ", ", $canv->canvasy($y), "\n
+";   
}

[download]

Doesn't work:

         $canvas{'ref'}->CanvasBind("<1>" =>
                  sub{
                        my $screenX = Ev('x');
                        my $screenY = Ev('y');
                        my $x = $canvas{'ref'}->canvasx($screenX);
                        my $y = $canvas{'ref'}->canvasy($screenY);
                        print "($x,$y)\n";
                     });

[download]
The second bit of code gives me 'bad screen distance x', which I know from trying is what I get when I dereference $x. I've tried various bits of dereferencing and such playfulness with the $screenX and $x values, and various things to try and get useful data, but it is all for not. I suspect there's something fundamental that is different which I don't know; can anyone shed some light on my conundrum? Thanks!

In reply to Tk::canvas - Cavas coord problem by Anonymous Monk

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