[Lazarus] Information about Docking

[Paul Ishenin]

Hans-Peter Diettrich wrote:
> I've been looking at the docking feature(s) of Lazarus, and would like 
> to know more about the current implementation. Where should I look for?

At the ldocktree.pas unit and ofcource controls.pp.

> One of the most important question is about the general overview of the 
> docking concept, from the technical point of view. I assume that there 
> must exist one application-wide manager (singleton?), that manages all 
> the related windows?
> 
> Does there exist another docking manager, apart from anchor docking? 

Yes, TLazDockTree.

> With sample code?

Use any delphi example.

> IMO anchor docking is a nice idea, but not very useful in practice. What 
> will happen to such a (spiral...) layout, when the container form is 
> resized? Not to mention other possible and existing problems...

We have plans to use it in the IDE mostly.

> What I want to achieve and contribute:
> 
> - Docking by drag&drop, at least for Windows and Linux. A proof of 
> concept in the first place, I've been warned ;-)

You can start with simple docking. You need to add ldocktree.pas into 
any of your uses sections to change DockManager class from dummy to 
working. Then create a delphi like example and start to play with it.

Most of things will work on windows. Drag/Dock will not work on linux 
because we cannot know when user start drag a window. Window title is 
owned by a window manager and gtk/qt does not report us about this 
event. Thus the first thing to implement is a special dock header which 
will be used on systems which cannot report us about titlebar drag.

Nobody looked at docking on OSX.

> - Old fashion (orthogonal/notebook) docking - if not yet implemented?

Implemented but it was so long ago when I checked it.

> - Multiple editor windows and related explorers. This was my first idea, 
> that lead me straight to the docking problems.

This can be done when all docking will 100% work on simple applications. 
And Mattias had an idea to use anchor docking.

You can even try how it works in IDE. Open your 
lazarus\ide\include\ide.inc file and add there:
{$define EnableIDEDocking}

Then recompile your IDE.

> Which Lazarus revision (trunk/tag) should I use for my first steps?
> I also think that I must create my own (local) repository, so that I can 
> share my modifications across various platforms (VM's). Any better idea?

Always use svn version if you want to send us patches. Get it here:
http://svn.freepascal.org/svn/lazarus/trunk

Best regards,
Paul Ishenin.