Oh, the image only zooms because I deal with it separately by redrawing the image at the appropriate scale every time the canvas is zoomed.

#####----- 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'
+);
[download]

It's just the object scaling (that I try to do with $CW->scale()) that doesn't work and that gives me the aforementioned error.

I'll try out your code (assuming it's tested) to ensure there is nothing wrong with my Tk. If there isn't I'm going to take the non-essential stuff out of my code and if it still doesn't work, I'll post it here!

Thanks,

I'll try out your code (assuming it's tested)

Yes, it's well tested standard code. If you want to zoom text, you can configure the font object to use a scaled up point size. Rebuilding the font, just as you rebuild a new image.

#!/usr/bin/perl
use warnings;
use strict;
use Tk;
require Tk::Font;

#by originally by Chris Lamprecht
my $MAIN    = new MainWindow;

my $canvas  = $MAIN->Canvas()->pack(-expand => 'yes',
    -fill =>'both');
my  $initial_fontsize = 24;
my  $scaling_factor   = 1;
my  $l_text = "current scaling_factor : $scaling_factor";
my  $helveticaStd = $MAIN->Font(-family=> 'Arial', -size  => $initial_
+fontsize);

my $text    = 'This is some text';
$canvas->createText(50,50,
    -text   => $text,
    -anchor => 'nw',
    -font   => $helveticaStd);
$canvas->createRectangle(47,47,290,87);

for my$fac (0.8,1.2){
   $MAIN->Button(-text    => "Scale by $fac",
      -command => [\&scaling,$fac]
       )->pack;
}
$MAIN->Label(-textvariable=>\$l_text)->pack;
MainLoop;

sub scaling{
   $scaling_factor *= $_[0];
   $canvas->scale('all',0,0,$_[0],$_[0]);
   $helveticaStd->configure(-size=>$initial_fontsize * $scaling_factor
+);
   $l_text = "current scaling_factor : $scaling_factor";
}
__END__
[download]

---

I'm not really a human, but I play one on earth.
Old Perl Programmer Haiku ................... flash japh

Alright, I think I've almost isolated the problem, but I feel no closer to a solution--without someone else's help, that is. :)

Let me illustrate with 2 contrasting examples. These examples only test ovals because they are the objects that are truly causing me trouble.

So first, when I run the whole out of one file, as you did in your example, I have no problem. The ovals scale properly and I get no error messages See code below.

However, when I have a MW in a separate file which invokes the second window containing the canvas, the ovals don't scale and I get a whole wack of problems, including the original one.

Here is the code:

Any ideas?

When I run your review2.pm, I get your error. But I added a line which shows the problem. I can't figure out why it allowed you to create an Oval to begin with.?

sub paint_Info{
 
 #this shows the problem   
 my ($MW, $CW, $zoom) = @_; 
 print "\n\n@_\n\n";

    $CW->createOval( 30, 30,
                     15, 15,
                     -outline => 'red', -width => 2,
                     -tags    => ['INFO']);

    my $zfactor = ($zoom > 0) ? $zoom : -1 / $zoom;
    $CW->scale('all', 0, 0, $zfactor, $zfactor);
}
[download]

When you print out @_, you get
MainWindow=HASH(0x7b8078) Tk::Frame=HASH(0xe2bfb0) 1
You then take $_1 and try to run Canvas methods on it. Scale will not run on a Frame, that is a Canvas method.

It just dawned on me! Your Frame is the Scrolled Frame the Canvas is in. Try getting the real canvas in your module. This fixes it! :-)

 
sub paint_Info                            #  ($MW, $Config)
{
    my ($MW, $CW, $zoom) = @_;

print "\n\n@_\n\n";

    my $canvas = $CW->Subwidget('canvas');

    $canvas->createOval( 30, 30,
                     15, 15,
                     -outline => 'red', -width => 2,
                     -tags    => ['INFO']);

    my $zfactor = ($zoom > 0) ? $zoom : -1 / $zoom;
    $canvas->scale('all', 0, 0, $zfactor, $zfactor);
}
[download]

---

I'm not really a human, but I play one on earth.
Old Perl Programmer Haiku ................... flash japh

That fix works for me too! Thanks! =D

Sorry, but I don't think I understand why this is necessary. Why didn't I have this problem when I had the whole thing running out of a single file?

Thanks,
Perldough