An Example:

use Tk;
use Tk::Canvas;
use Tk::Label;

my $mw = tkinit(-title, 'Canvas');
#$mw->geometry('250x250');
my $frame = $mw->Frame(-width, 250, -height, 250)->pack(-fill, 'both',
+ -expand,1);
my $canvas = $frame->Scrolled('Canvas', -width, 600, -height, 600, 
    -scrollbars, 'osoe'
    )->pack(-fill,'both',-expand,1);

my $btn = $mw->Button(-text, "Add Stuff", -command,\&addStuff)
    ->pack();


MainLoop;

sub addStuff{
    $canvas->createText(500, 500, -text, "Some text @ 500, 500." );
    $canvas->createRectangle(  50,  50, 110, 110, -fill, 'red');
    $canvas->createRectangle( 150, 150, 210, 210, -fill, 'green');
    $canvas->createRectangle( 250, 250, 310, 310, -fill, 'blue');
    $canvas->createText(20, 20, -text, "Some text @ 20, 20." );
#
# Your can use an array for your bounding box
# commented out to show both ways to set the scrollregion
# Just make sure you are 1 less on lower right and bottom
# Or you will have out of bounds array... easy to forget
# if you don't use a frame with your canvas

#$canvas->configure(-scrollregion => [ 0, 0, 599, 599]);
    $canvas->configure(-scrollregion => [$canvas->bbox('all')]);
}
[download]

Update: commented out initial geometry
JamesNC