Update a custom property after leaving edit-mode?

Question

I'm looking for a way to automatically run the update_length() function after editing the actual curve, this would make my curve_length property always be up to date.

import bpy
obj = bpy.context.object
bpy.types.Object.curve_length = bpy.props.FloatProperty(
    name = 'Curve Length',
    description = 'Curve Length',
    default = 0
    )
def calculate_curve_length (obj):
    curve_length = obj.data.splines[0].calc_length()
    return curve_length
def update_length()
    obj.curve_length = calculate_curve_length (obj)
update_length()

May find this of interest https://blender.stackexchange.com/a/159719/15543 — batFINGER, Jun 26 '20 at 15:36

ideasman42 · Accepted Answer · 2020-06-26T07:13:15.413

6

You can subscribe to changes in an objects mode.

import bpy
Create a unique object as a handle for the subscriber.
my_handle = object()
def my_notify(a, b, c):
    print(a, b, c)
def register():
    bpy.msgbus.subscribe_rna(
        key=(bpy.types.Object, "mode"),
        owner=my_handle,
        # Can be anything, passed to 'notify'.
        args=(1,2,6),
        notify=my_notify,
    )
def unregister():
    # Clear on unregister.
    bpy.msgbus.clear_by_owner(my_handle)
register()
```

edited Jun 26 '20 at 07:13

answered Jun 26 '20 at 06:45

ideasman42

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Hi. Couple of queries. Is there a way to get the instances causing the notification other than via context? And if using context would you recommend passing it as a subscribe arg or using bpy.context in method. – batFINGER Jun 26 '20 at 08:00
1

@batFINGER off hand I don't think so, although it should be supported, I'll need to double check on this. – ideasman42 Jun 26 '20 at 08:33

Update a custom property after leaving edit-mode?

1 Answers1

Create a unique object as a handle for the subscriber.