I have a canvas named CW in which I have a picture and a whole bunch of overlain objects such as text and circles. I need to be able to zoom in on the picture and have the overlain objects stay at the same spot on the picture. I tried doing it like this.

#####----- Show zoomed picture -----#####
# $zoom is number between -4 and 3;  Negative for zoom-out and positiv
+e for zoom-in as worked out in the conditional statement.
# $img is the original image.
# $zimg is the zoomed image.
$zimg = $MW->Photo();
($zoom > 0) ? $zimg->copy($img, -zoom      => $zoom)
            : $zimg->copy($img, -subsample => ($zoom * -1));
$CW->createImage(0,0, -anchor => 'nw', -image => $zimg, -tags => 'dwg'
+);

###-- Omited: Create objs in $CW w/ orig dims --###

###-- Scale objects --###
$zfactor is one of (0.25, 0.3, 0.5, 1, 2, 3)
my $zfactor = ($zoom > 0) ? $zoom : -1 / $zoom;
$CW->scale('all', 0, 0, $zfactor, $zfactor);
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Tk::Error: bad window path name "all" at review.pm line 335.
Tk callback for scale
RC::paint_Info at review.pm line 335
RC::__ANON__ at review.pm line 101
Tk callback for .toplevel.frame.labframe.border.frame1.radiobutton2
Tk::__ANON__ at C:/Perl/site/lib/Tk.pm line 250
Tk::Radiobutton::Invoke at C:/Perl/site/lib/Tk/Radiobutton.pm line 42
<Button-1>
(command bound to event)