Binary package “tk-itk4” in ubuntu focal
[incr Tk] OOP extension version 4 for Tk - run-time files
[incr Tk] (or itk) combines the object-oriented power of [incr Tcl]
with the popular Tk graphical toolkit to create a framework for
creating mega-widgets. One such set of mega-widgets is provided by
the iwidgets package.
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This package contains everything you need to run itk scripts and
itk-enabled apps.