Author:         Harald Oehlmann <[email protected]>
State:          Voting
Type:           Project
Created:        03-May-2025
Tcl-Version:    9.1
Tk-Branch:      rfe-d632d28ba4
Keywords:       ttk::treeview

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Abstract

This TIP proposes to add new states to allow to change images of the ttk::treeview and ttk::notebook widgets in dependency of widget item states.

Background

The original request is this Tk ticket d632d28ba4.

Starting with Tk 9.0, the assignment state dependent images for the tree indicators of a ttk::treeview widget is not possible any more, as the so far used states "user1" and "user2" are not assigned any more by the treeview code.

The proposal is to assign new state codes which are dedicated to the usage. In addition, the notebook widget has the same issue, that first or last tab image may vary in the form.

Rationale

Make it possible to assign state dependent ttk::treeview indicator images.

The following code worked in Tk 8.6:

ttk::style element create Treeitem.indicator \
              image [list $image_for_closed \
                  user1 $image_for_open \
                  user2 $image_for_no_children \
              ]

It does not work in Tk 9.0.

In Tk 9.1, this may be replaced by:

ttk::style element create Treeitem.indicator \
              image [list $image_for_closed \
                  open $image_for_open \
                  leaf $image_for_no_children \
              ]

The same is for ttk::notebook, where the tab images may require to know, if there are any neighbours.

Specification

Add the following new states and addign them to the ttk::treeview widget:

*   leaf: leaf with no children indicator
*   open: open leaf indicator

In addition, add the following states for the notebook widget:

*   first: first tab
*   last: last tab

Compatibility

Fully backward compatible to Tk 9.0. Incompatible to 8.6 by design and purpose, as the usage of user1 and user2 was seen as an abuse.

Discussion

Reference Implementation

A reference impementation can be found in Tk branch rfe-d632d28ba4.

Copyright

This document has been placed in the public domain.