Tag_redraw() from draw callback

Technical Support Python Support
1

I have an operator which registers a draw callback and it’s working fine. Now, I would like to decide from within the draw callback that another redraw should happen next frame. However, calling context.area.tag_redraw() from within the draw callback appears to have no effect.

def invoke(self, context: bpy.types.Context, event: bpy.types.Event):
    args = (self, context, event)
    self.drawCallbackHandle = bpy.types.SpaceView3D.draw_handler_add(drawCallback, args, "WINDOW", "POST_PIXEL")

# ...

def drawCallback(op: MyOperator, context: bpy.types.Context, event: bpy.types.Event):
    now = time.perf_counter()
    holdTime = 1
    since = now - op.timeOfSomeEvent
    if since >= holdTime:
        return
    # draw something
    context.area.tag_redraw() # draw again soon <- this doesn't work

Essentially I want to use this to animate a text fadeout, but no redraw happens unless I get an event to call tag_redraw() from my operator. Any ideas?

2

I woke up with an idea today, and it works perfectly.

bpy.app.timers.register(context.area.tag_redraw, first_interval = 0)