add observer method

src/compas_viewer/observer.py

@@ -0,0 +1,35 @@
+from PySide6.QtCore import QTimer
+
+from compas_viewer.base import Base
+
+
+class Observer(Base):
+    def __init__(self):
+        self._observers = set(
+            (
+                self.viewer.renderer,
+                self.viewer.ui.sidebar,
+            )
+        )
+
+        self._time = None
+        self.update_timer = QTimer()
+        self.update_timer.setSingleShot(True)
+        self.update_timer.timeout.connect(self.update_observers)
+        self.debounce_interval = 100
+
+    def add_observer(self, observer):
+        if observer not in self._observers:
+            self._observers.add(observer)
+
+    def remove_observer(self, observer):
+        if observer in self._observers:
+            self._observers.remove(observer)
+
+    def request_update(self):
+        if not self.update_timer.isActive():
+            self.update_timer.start(self.debounce_interval)
+
+    def update_observers(self):
+        for observer in self._observers:
+            observer.update()

src/compas_viewer/scene/sceneobject.py

@@ -16,6 +16,7 @@
 from compas_viewer.gl import make_vertex_buffer
 from compas_viewer.gl import update_index_buffer
 from compas_viewer.gl import update_vertex_buffer
+from compas_viewer.observer import Observer
 from compas_viewer.renderer.shaders import Shader
 
 # Type template of point/line/face data for generating the buffers.
@@ -101,6 +102,9 @@ def __init__(
     ):
         #  Basic
         super().__init__(**kwargs)
+
+        self.observer = Observer()
+
         self.show = show
         self.show_points = show_points if show_points is not None else False
         self.show_lines = show_lines if show_lines is not None else True
@@ -111,7 +115,7 @@ def __init__(
 
         #  Selection
         self._is_locked = is_locked
-        self.is_selected = not is_locked and is_selected
+        self._is_selected = False
 
         #  Visual
         self.background: bool = False
@@ -135,6 +139,16 @@ def __init__(
 
         self._inited = False
 
+    @property
+    def is_selected(self):
+        return self._is_selected
+
+    @is_selected.setter
+    def is_selected(self, value):
+        if self._is_selected != value:
+            self._is_selected = value
+            self.observer.request_update()
+
     @property
     def is_locked(self):
         return self._is_locked