Observe point changes/movements?

StephenNixon

I'm hoping to record the changes made to points in glyphs. My current plan is to make a dictionary of point locations when a glyph is opened (or possibly just accessing the glif data), then comparing point locations when points are moved, and making a dictionary of point movements.

Is there an observer that can send a notification when points are moved?

I'm hoping for something along the lines of pointMovedInCurrentGlyph, so I could add something like this to my code...

addObserver(self, 'recordPointMovement', "pointMovedInCurrentGlyph") # fake code

...but I'm not finding anything obvious.

Am I missing something? How might I best approach this?

StephenNixon

Makes sense. Thanks so much for your help!

frederik

a script or something else like fe a transormation from the inspector

StephenNixon

Ohh of course, that is simpler than I was thinking!

I suppose that the only time points would move without being selected is if they were moved by a script, right?

frederik

the Contour.PointsChanged calls your callback with a notification object:

notification.object # in this case the contour object
notification.data # optional data related to the event, in this case it will be None

this notification is sent on different events: inserting, removing, changing start point...

in most cases the moved points are the selected ones:

glyph.selectedPoints

StephenNixon

It's working nicely to show that a point moved!

Is there a simple way to know which point moved, once I get the notification? The notification I receive is:

Contour.PointsChanged --> <lib.fontObjects.doodleContour.DoodleContour object at 0x112f24320>

Ideally, I'd want to get to data which was the point index with its parent contour index.

If I print notification.data, it only gives None.

Does the object at 0x112f24320 mean anything?

Would I have to do something like looping through all points to compare them to a "before" state (possibly in another layer), then assign changed points a unique identifier with generateIdentifierForPoint(point)?

StephenNixon

@frederik said in Observe point changes/movements?:

Contour.PointsChanged

Amazing, thank you! I'll give this a shot tonight and see where it gets me.

frederik

There is a Contour.PointsChanged notification for a contour object.

There are no notifications for each point object.

a tiny script that shows all font level notifications:


import vanilla


class AllNotifications(object):
    
    def __init__(self):
        
        self.w = vanilla.Window((400, 400), minSize=(200, 200))
        self.w.e = vanilla.TextEditor((0, 0, 0, 0))
        # keep a ref otherwise weak ref will not work
        self.w._ref = self
        self.w.bind("close", self.windowClose)
        self.w.open()
        
        self.font = CurrentFont().naked()        
        self.font.dispatcher.addObserver(self, "callback", notification=None, observable=None)
    
    def windowClose(self, sender):
        # remove the observer
        self.font.dispatcher.removeObserver(self, notification=None, observable=None)
        # remove the references
        del self.w._ref    
        del self.font
        
    def callback(self, notification):
        txt = "\n%s --> %s" % (notification.name, notification.object)        
        self.w.e.set(self.w.e.get() + txt)
 
 
AllNotifications()

SOLVED Observe point changes/movements?