TreeItem add move up/down function

[TheDuriel]

Godot version:

3.1

Issue description:

Right now TreeItem implements move_to_top() and move_to_bottom() to move the item to the first or last position among its siblings.

I would like the ability to move an Item by an arbitrary amount. I am currently building a modding system ala skyrim, and need to ability to move tree items to arbitrary positions in the list.

[akien-mga]

Makes sense, though I'm not sure if that can be added to TreeItem itself, I guess it would have to be a method of Tree? E.g. Tree.move_item(int p_item, int p_new_position). Or maybe it is possible in TreeItem, with something like TreeItem.move_up/down(int p_amount), as long as it's able to gracefully handle out of bound moves (e.g. you're moving TreeItem idx 3 up by 6, it should become the first item (0) as if you only moved it by 3).

[TheDuriel]

Either way is fine with me <3

[Anutrix]

Any comments on which one of these is better? Polls on github would be nice.

Makes sense, though I'm not sure if that can be added to TreeItem itself, I guess it would have to be a method of Tree? E.g. Tree.move_item(int p_item, int p_new_position). Or maybe it is possible in TreeItem, with something like TreeItem.move_up/down(int p_amount), as long as it's able to gracefully handle out of bound moves (e.g. you're moving TreeItem idx 3 up by 6, it should become the first item (0) as if you only moved it by 3).

[akien-mga]

Well it's not a matter of polling, but of checking the actual implementations of Tree, TreeItem and their interactions, to see what is possible / makes sense given their design.

The Tree/TreeItem APIs are a bit peculiar, and it seems item management mainly goes through TreeItem (where a TreeItem can give you a reference to its previous or next TreeItem in the parent Tree), so I suppose that's where the move methods would have to go, even if it stays a slightly unintuitive API.

But again I haven't checked the code, those are just some comments to point interested contributors in possible directions :)

[girng]

forgive me if i am mistaken, but since the node scene list in the editor lets you drag to any position, this should be possible already?

[TheDuriel]

@girng The editor implementation is not as straightforward. The entire drag and drop system for it is a custom implementation. Remember that it actually modifies a Scene Tree, the dock simply displays it after a change happens. This works because the tree structure itself is not actually managed using the Tree class.

https://github.com/godotengine/godot/blob/master/editor/scene_tree_dock.cpp

[girng]

@TheDuriel interesting, TIL. nvm my prev comment then :p. ty

[marzecdawid]

Is it still valid proposal after #46773? TreeItem.move_up/down(int p_amount) may still be more practical in some cases than move_before/after.

[TheDuriel]

I think that #46773 functionally solves this, though it's very awkward.

Say you want to move a node one down in the tree:

self.move_after(self.get_next())

And move it two up.

for i in 2:
    self.move_before(self)

A dedicated move_up(x) move_down(x) and raise() would be preferable.