ungroupOnCanvas does not ungroup and does not restore object state correctly.

[virror]

Version

3.6.3

Test Case

https://jsfiddle.net/Lmxb9qdu/3/

Information about environment

Firefox, Chrome

Steps to reproduce

Run fiddle, select both boxes and press "Group" button, then press "Ungroup" button and click on canvas to get rid of selection.

Expected Behavior

I expect what the docs says: "Destroys a group (restoring state of its objects) ".
That the group gets destroyed and the objects are restored.

Actual Behavior

Group is not destroyed at all, and the objects changes their position.

One way of working around this is to make sure the selection is removed first, and then destroy the group manually. This seems to get the expected behavior (imo):

canvas.discardActiveObject()
object.ungroupOnCanvas()
canvas.remove object

[awehring]

I have never used a group (besides activeSelection). But there is a tutorial on how to work with them. Your example doesn't follow it.

http://fabricjs.com/fabric-intro-part-3#groups

BTW to create and expand an activeSelection works somewhat different. See #6130
Propably it is the same with groups.

[virror]

Well, the functionality does not follow what the docs says either, so ether the bug is in the docs, or in the functionality : )

Edit: And the ungroupOnCanvas is not mentioned in the tutorial at all, so there is no way to know for certain how to use that function.

Edit2: Actually the tutorial does not at all mention how to get rid of groups.

[asturur]

my memory is short on what ungroupOnCanvas is suppoesed to do ( git blame to the rescue ).
The only real way to move from group to separated objects quickly is to use

toActiveSelection.

ActiveSelection.toGroup and Group.toActiveSelection are supposed to work on with the other.

http://fabricjs.com/manage-selection

[asturur]

unGroupOnCanvas seems something that was created ( 3 years ago ) never used elsewhere, maybe thought of being fo public utility but i do not think it is.

I think i should delete it in the beta of version 4 and just put it as a breaking change.

And by the way unGroupOnCanvas just call _restoreObjectsState that seems like just calling itself again, like if it was broken/misspelled.

Does it even work?

[awehring]

With some distance:
The jsfiddle code is group = canvas.getActiveObject();
ActiveSelection is an extension to the Group Class. So simply assigning one to the other might give unexpected results.

[virror]

Yes, i have seen that example also and "toActiveSelection" was the first thing i tried.
What im doing is that i dont want to have "stacked" groups, so when i group something with a group, i have to break down the group first and regroup it so all objects are in the base group.

For actual user ungrouping i use "toActiveSelection". But using "toActiveSelection" made stuff move around on the canvas unexpectedly when it was part of a selection and i did not get it to work correctly, thats why i looked for an alternative way on ungrouping.

[virror]

Yes, might be best to just remove it. I might have to try again to get it to work with the "toActiveSelection" instead, even though it works fine now with "unGroupOnCanvas" when manually removing the group afterwards.

[asturur]

So you are looking that is like flattenGroup. That could be a feature eventually if it requires too much logic in an app.
I can see how someone does not want to pass trought many manual deselection process to do that.

[virror]

Yes, that exactly what im trying to do. Saving the state is just to bothersome when its stacked : p
Im trying to make a fiddle and see if i can make it work with "toActiveSelection" instead.

[virror]

Ok, finally managed to get it to work:
https://jsfiddle.net/1p732srw/

I guess this issue can be closed now then if "unGroupOnCanvas" is going to get removed anyways : )