If a monospaced font is the solution (as it let you to align chars), it's very easy to use it in Tk. Tk::Font names Courier as a monospaced ``typewriter'' font.

You can create a font in your Tk application, for a later use:

$mono_font = $mw->fontCreate('mono', -family => 'Courier', -size => 10
+);
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After you can use it by name mono or by using the variable $mono_font

$mw->Label(-text => "test monospaced font", -font => 'mono');
$mw->Label(-text => "test monospaced font bis", -font => $mono_font);
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If you want all object of some class, or all widgets in the program to have the same font (or color, or size..) you can use the "options database" Tk uses:

$mw->optionAdd('*font', 'Courier 12');
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L*

PS

You can specify -font directly int Text or ROText object, you'll anyway need a padding tecnique:

#pay attention to win32 doublequotes!

perl -MTk -e "$mw=tkinit;$t=$mw->Text(-font=>'Courier')->pack;$t->inse
+rt('end', $_.(' ' x (10 - length $_)).qq(xxx\n)) for qw (aaaa bbb ccc
+ccc);MainLoop"
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PPS see Tk font size for ALL widgets