Fix size hint bug in relayout.

Fix bug in wx layout timer.

enaml/qt/qt_constraints_widget.py

@@ -126,7 +126,6 @@ def relayout(self):
         layout request is dropped.
 
         """
-        self.clear_size_hint_constraints()
         parent = self.parent()
         if isinstance(parent, QtConstraintsWidget):
             parent.relayout()
@@ -155,40 +154,6 @@ def replace_constraints(self, old_cns, new_cns):
         if isinstance(parent, QtConstraintsWidget):
             parent.replace_constraints(old_cns, new_cns)
 
-    def clear_constraints(self, cns):
-        """ Clear the given constraints from the current layout system.
-
-        The default behavior of this method is to proxy the call up the
-        tree of ancestors until it is either handled by a subclass which
-        has reimplemented this method (see QtContainer), or the ancestor
-        is not an instance of QtConstraintsWidget, at which point the
-        request is dropped. This method will *not* trigger a relayout.
-
-        Parameters
-        ----------
-        cns : list
-            The list of casuarius constraints to remove from the
-            current layout system.
-
-        """
-        parent = self.parent()
-        if isinstance(parent, QtConstraintsWidget):
-            parent.clear_constraints(cns)
-
-    def clear_size_hint_constraints(self):
-        """ Clear the size hint constraints from the layout system.
-
-        """
-        # Only the ancestors of a widget care about its size hint and
-        # will have added those constraints to a layout, so this method
-        # attempts to replace the size hint constraints for the widget
-        # starting with its parent.
-        parent = self.parent()
-        if isinstance(parent, QtConstraintsWidget):
-            cns = self.size_hint_cns
-            del self.size_hint_cns
-            parent.clear_constraints(cns)
-
     def size_hint_updated(self):
         """ Notify the layout system that the size hint has changed.
 

enaml/qt/qt_container.py

@@ -196,17 +196,9 @@ def relayout(self):
 
         """
         if self._owns_layout:
-            item = self.widget_item
-            old_hint = item.sizeHint()
-            self.init_cns_layout()
-            self._refresh()
-            new_hint = item.sizeHint()
-            # If the size hint constraints are empty, it indicates that
-            # they were previously cleared. In this case, the layout
-            # system must be notified to rebuild its constraints, even
-            # if the numeric size hint hasn't changed.
-            if old_hint != new_hint or not self.size_hint_cns:
-                self.size_hint_updated()
+            with size_hint_guard(self):
+                self.init_cns_layout()
+                self._refresh()
         else:
             self._layout_owner.relayout()
 
@@ -238,23 +230,6 @@ def replace_constraints(self, old_cns, new_cns):
         else:
             self._layout_owner.replace_constraints(old_cns, new_cns)
 
-    def clear_constraints(self, cns):
-        """ Clear the given constraints from the current layout.
-
-        Parameters
-        ----------
-        cns : list
-            The list of casuarius constraints to remove from the
-            current layout system.
-
-        """
-        if self._owns_layout:
-            manager = self._layout_manager
-            if manager is not None:
-                manager.replace_constraints(cns, [])
-        else:
-            self._layout_owner.clear_constraints(cns)
-
     def contents_margins(self):
         """ Get the contents margins for the container.
 
@@ -436,9 +411,13 @@ def _generate_constraints(self, layout_table):
         cns.extend(expand_constraints(d, d.layout_constraints()))
 
         # The first element in a layout table item is its offset index
-        # which is not relevant to constraints generation.
+        # which is not relevant to constraints generation. The child
+        # size hint constraints are refreshed unconditionally. This
+        # accounts for the potential changes in the size hint of a
+        # widget between relayouts.
         for _, updater in layout_table:
             child = updater.item
+            del child.size_hint_cns
             d = child.declaration
             cns.extend(hard_constraints(d))
             if isinstance(child, QtContainer):

enaml/qt/qt_flow_area.py

@@ -178,12 +178,3 @@ def replace_constraints(self, old_cns, new_cns):
 
         """
         pass
-
-    def clear_constraints(self, cns):
-        """ A reimplemented QtConstraintsWidget layout method.
-
-        Constraints layout may not cross the boundary of a FlowArea,
-        so this method is no-op which stops the layout propagation.
-
-        """
-        pass

enaml/qt/qt_scroll_area.py

@@ -192,15 +192,6 @@ def replace_constraints(self, old_cns, new_cns):
         """
         pass
 
-    def clear_constraints(self, cns):
-        """ A reimplemented QtConstraintsWidget layout method.
-
-        Constraints layout may not cross the boundary of a ScrollArea,
-        so this method is no-op which stops the layout propagation.
-
-        """
-        pass
-
     #--------------------------------------------------------------------------
     # ProxyScrollArea API
     #--------------------------------------------------------------------------

enaml/wx/wx_constraints_widget.py

@@ -41,6 +41,7 @@ class wxLayoutTimer(wx.Timer):
 
     """
     def __init__(self, owner):
+        super(wxLayoutTimer, self).__init__()
         self.owner = owner
 
     def Release(self):
@@ -112,7 +113,7 @@ def request_relayout(self):
         if not self.layout_timer:
             self.widget.Freeze()
             self.layout_timer = wxLayoutTimer(self)
-        self.layout_timer.start(5, oneShot=True)
+        self.layout_timer.Start(1, oneShot=True)
 
     def on_layout_triggered(self):
         """ Handle the timeout even from the layout trigger timer.
@@ -139,7 +140,6 @@ def relayout(self):
         layout request is dropped.
 
         """
-        self.clear_size_hint_constraints()
         parent = self.parent()
         if isinstance(parent, WxConstraintsWidget):
             parent.relayout()
@@ -168,40 +168,6 @@ def replace_constraints(self, old_cns, new_cns):
         if isinstance(parent, WxConstraintsWidget):
             parent.replace_constraints(old_cns, new_cns)
 
-    def clear_constraints(self, cns):
-        """ Clear the given constraints from the current layout system.
-
-        The default behavior of this method is to proxy the call up the
-        tree of ancestors until it is either handled by a subclass which
-        has reimplemented this method (see WxContainer), or the ancestor
-        is not an instance of WxConstraintsWidget, at which point the
-        request is dropped. This method will *not* trigger a relayout.
-
-        Parameters
-        ----------
-        cns : list
-            The list of casuarius constraints to remove from the
-            current layout system.
-
-        """
-        parent = self.parent()
-        if isinstance(parent, WxConstraintsWidget):
-            parent.clear_constraints(cns)
-
-    def clear_size_hint_constraints(self):
-        """ Clear the size hint constraints from the layout system.
-
-        """
-        # Only the ancestors of a widget care about its size hint and
-        # will have added those constraints to a layout, so this method
-        # attempts to replace the size hint constraints for the widget
-        # starting with its parent.
-        parent = self.parent()
-        if isinstance(parent, WxConstraintsWidget):
-            cns = self.size_hint_cns
-            del self.size_hint_cns
-            parent.clear_constraints(cns)
-
     def size_hint_updated(self):
         """ Notify the layout system that the size hint has changed.
 

enaml/wx/wx_container.py

@@ -207,18 +207,10 @@ def relayout(self):
 
         """
         if self._owns_layout:
-            widget = self.widget
-            old_hint = widget.GetBestSize()
-            self.init_cns_layout()
-            if self._is_shown:
-                self._refresh()
-            new_hint = widget.GetBestSize()
-            # If the size hint constraints are empty, it indicates that
-            # they were previously cleared. In this case, the layout
-            # system must be notified to rebuild its constraints, even
-            # if the numeric size hint hasn't changed.
-            if old_hint != new_hint or not self.size_hint_cns:
-                self.size_hint_updated()
+            with size_hint_guard(self):
+                self.init_cns_layout()
+                if self._is_shown:
+                    self._refresh()
         else:
             self._layout_owner.relayout()
 
@@ -251,23 +243,6 @@ def replace_constraints(self, old_cns, new_cns):
         else:
             self._layout_owner.replace_constraints(old_cns, new_cns)
 
-    def clear_constraints(self, cns):
-        """ Clear the given constraints from the current layout.
-
-        Parameters
-        ----------
-        cns : list
-            The list of casuarius constraints to remove from the
-            current layout system.
-
-        """
-        if self._owns_layout:
-            manager = self._layout_manager
-            if manager is not None:
-                manager.replace_constraints(cns, [])
-        else:
-            self._layout_owner.clear_constraints(cns)
-
     def contents_margins(self):
         """ Get the contents margins for the container.
 
@@ -447,9 +422,13 @@ def _generate_constraints(self, layout_table):
         cns.extend(expand_constraints(d, d.layout_constraints()))
 
         # The first element in a layout table item is its offset index
-        # which is not relevant to constraints generation.
+        # which is not relevant to constraints generation. The child
+        # size hint constraints are refreshed unconditionally. This
+        # accounts for the potential changes in the size hint of a
+        # widget between relayouts.
         for _, updater in layout_table:
             child = updater.item
+            del child.size_hint_cns
             d = child.declaration
             cns.extend(hard_constraints(d))
             if isinstance(child, WxContainer):

enaml/wx/wx_scroll_area.py

@@ -193,15 +193,6 @@ def replace_constraints(self, old_cns, new_cns):
         """
         pass
 
-    def clear_constraints(self, cns):
-        """ A reimplemented WxConstraintsWidget layout method.
-
-        Constraints layout may not cross the boundary of a ScrollArea,
-        so this method is no-op which stops the layout propagation.
-
-        """
-        pass
-
     #--------------------------------------------------------------------------
     # ProxyScrollArea API
     #--------------------------------------------------------------------------