Tk Concepts

For those new to Tk, it is useful to understand some concepts of Tk as we loosely follow the standard Tk widget behavior. Generally, widgets are GUI elements like buttons and sliders. The loon scatterplot display and inspector can be considered as megawidgets; a widget that combines several other widgets but behaves like a normal widget itself. Every widget in a Tk session has a unique hierarchical window path name with the root being a dot . and children and parents are separated by a dot. Hence a typical widget path name for a widget button with three ancestors (root, frameA and frameB) is .frameA.frameB.button where the user is free to name all the nodes (except the root) as he/she wishes. When a Tk widget gets created a function with the function name equivalent to the widget path name gets created to query or modify the widget. For example in tkcon run

package require Tk
button .b -text "Hello World"
pack .b
info commands

and you will see a button with the label "Hello World" and the output for info commands will list the function .b.

The widget function can be used to query and modify the widget options via cget and configure. For example continuing with the above example

.b configure -text "A new label"
.b cget -text

A more detailed introduction to the Tk Concepts can be read on tkdocs.com.