Sorry, Image::Magick hasn't what you are looking for; you can of course build your own system using QueryFontMetrics; here is an example of its usage:

#!/usr/bin/perl

use Image::Magick;

$i = Image::Magick->new;
$i->Set( size => '320x200' );
$i->ReadImage('xc:white');

@params = ( font      => '@arial.ttf',
            text      => 'some text',
            pointsize => 36 );

($w, $h,
 $ascend, $descend,
 $text_w, $text_h,
 $max) = $i->QueryFontMetrics( @params );
print "$w, $h, $ascend, $descend, $text_w, $text_h, $max\n";

$i->Annotate( @params,
              stroke  => red,
              fill    => red,
              gravity => center );

$i->Display;
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Second, going through Image::Magick's documentation, their support of text if not very advanced. Perhaps you'd find it easier to use GD::Text. Not only does it support TrueType fonts, but the width method will return the width of text in pixels - which is exactly what you need to determine where to wrap your string.

If you want to clip the text to a given area, you may want to (1) create a new separate image of just the writable area, write your text in that, then apply it to the larger image, or (2) draw the text before you draw the other elements, so that the other elements overwrite any stray parts of the text.

Determining the extent (the bounding box) of the written text (before or after drawing) can be tricky, but I think Perl::Magick offers some routines to determine that.

Deciding how to alter your text to fit within a given space is far more tricky, and is usually an iterative process that is almost like trial and error. You have to decide what can be altered: font size, word wrapping, word breaking, etc. There will always be some strings that just can't fit: supercalifragilisticexpialidocious won't fit in a 128x128 icon and remain legible.

!/usr/bin/perl
use strict;
use warnings;
use Image::Magick;

my $label = Image::Magick->new(
   size => "600x600",
);

$label->Read("xc:white");
$label->Draw(
   primitive => 'line',
   points    => "300,100 300,500",
   stroke    => '#600',
);

$label->Draw(
   primitive => 'line',
   points    => "100,300 500,300",
   stroke    => '#600',
);

$label->Draw(
   primitive => 'rectangle',
   points    => "100,100 500,500",
   fill      => 'none',
   stroke    => '#600',
);

my $x = $label->Annotate(
   text      => "North West",
   'x'       => 150,
   'y'       => 150,
   pointsize => 40,
  # font      => $ENV{WINDIR}.'\Fonts\Tahomabd.ttf', 
    font     => 'arial.ttf'
);

die "$x" if "$x";

$label->Write("$0.png");
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