Why property "frame_current" not updating every frame?

Coding Python Support
1

Hi, I create a panel with prop context.scene.frame_current, but it don’t updating every frame when you press Play, what to do?

import bpy;
from bpy.types import Panel;

class VIEW3D_PT_frame_test_panel (Panel):
    bl_space_type  = 'VIEW_3D';
    bl_region_type = 'UI';
    bl_category    = "Test";
    bl_label       = "Test Current Frame";
    
    def draw(self, context):
        layout = self.layout;
        
        layout.prop(context.scene, "frame_current");


bpy.utils.register_class(VIEW3D_PT_frame_test_panel);
2

Because the panel doesn’t update when you move the timeline. You have to call a function to update the panel whenever the value changes, like when the depsgraph changes, but perhaps this may not be the most optimal solution.

3

How I can do that?

4

This would be a nice case for the frame change handler:


import bpy
from bpy.types import Panel

class VIEW3D_PT_frame_test_panel(Panel):
    bl_space_type  = 'VIEW_3D'
    bl_region_type = 'UI'
    bl_category    = "Test"
    bl_label       = "Test Current Frame"
    
    def draw(self, context):
        layout = self.layout
        layout.prop(context.scene, "frame_current", text="Current Frame")

def frame_change_post_handler(scene):
    # from this screen get the view 3D and tag it for refresh
    for area in bpy.context.screen.areas:
        if area.type == 'VIEW_3D':
            area.tag_redraw()

# register the frame change handler
bpy.app.handlers.frame_change_post.append(frame_change_post_handler)


bpy.utils.register_class(VIEW3D_PT_frame_test_panel)
5

Thank you so much!