Version 2 of a proposal for a new FLTK widget : Fl_Dockable_Group

[Manolo]

Hi devs,

Please, see the version 2 of my proposal for a new FLTK class

to give FLTK support of docking/undocking operations:

  https://github.com/fltk/fltk/discussions/1257#discussioncomment-15163449

This is an improvement of my previous proposal that accounts  for remarks

made about version 1.

Manolo

[Gonzalo Garramuño]

On 12/4/25 14:26, Manolo wrote:
>
> This is an improvement of my previous proposal that accounts for remarks
> made about version 1.

Can you make a summary of the improvements?  I gave it a try and could
not tell the difference.

[Manolo]

Le lundi 22 décembre 2025 à 00:51:25 UTC+1, ggar...@gmail.com a écrit :

> This is an improvement of my previous proposal that accounts for remarks
> made about version 1.
Can you make a summary of the improvements?  I gave it a try and could
not tell the difference.

The main difference is that function Fl_Dockable_Group::target_box() that used to declare

a 'target box' where a dockable group could be docked has disappeared.

In version 2, Fl_Widget's that can become the target of a dockable group are application-defined

and FLTK does not limit them to Fl_Box-derived objects. That's comparable to the target widgets of a 

drag-and-drop operation in FLTK. Any widget can be one, but the application must make this widget 

respond appropriately to FL_DND_ events  to be a valid drop target.

With dockable groups, any widget can dock a dockable group but it must implement a few functions

to be a valid docking target. The application is therefore free to implement docking target widgets

as necessary for it, without FLTK deciding what can or cannot be a docking target.

Version 2 gives also more freedom for an app to decide what is a "drag widget", although

it's expected that an Fl_Box should most often fit to what is needed to undock and drag a dockable group.