# HG changeset patch
# User Goffi <goffi@goffi.org>
# Date 1575634983 -3600
# Node ID 4374cb741eb50bd8a8bc0df6b3ecbd58edd6533a
# Parent  5bd583d00594d62c97a651271bfd35472773ee69
core (common widgets): added a DelayedBoxLayout class:

DelayedBoxLayout delay the sizing, this is useful when sizing is complex and resource
consuming.

Thanks to https://blog.kivy.org/2019/07/a-delayed-resize-layout-in-kivy/

diff -r 5bd583d00594 -r 4374cb741eb5 cagou/core/common_widgets.py
--- a/cagou/core/common_widgets.py	Fri Dec 06 13:23:03 2019 +0100
+++ b/cagou/core/common_widgets.py	Fri Dec 06 13:23:03 2019 +0100
@@ -25,12 +25,30 @@
 from cagou.core.menu import TouchMenuItemBehaviour
 from kivy import properties
 from kivy.metrics import dp
+from kivy.clock import Clock
 from cagou import G
 from sat.core import log as logging
 
 log = logging.getLogger(__name__)
 
 
+class DelayedBoxLayout(BoxLayout):
+    """A BoxLayout with delayed layout, to avoid slowing down during resize"""
+    # XXX: thanks to Alexander Taylor for his blog post at
+    #      https://blog.kivy.org/2019/07/a-delayed-resize-layout-in-kivy/
+
+    do_layout_event = properties.ObjectProperty(None, allownone=True)
+    layout_delay_s = properties.NumericProperty(0.2)
+
+    def do_layout(self, *args, **kwargs):
+        if self.do_layout_event is not None:
+            self.do_layout_event.cancel()
+        real_do_layout = super().do_layout
+        self.do_layout_event = Clock.schedule_once(
+            lambda dt: real_do_layout(*args, **kwargs),
+            self.layout_delay_s)
+
+
 class Identities(object):
 
     def __init__(self, entity_ids):