Update the splitter implementation to support a stretch factor and a

collapse flag.

enaml/qt/qt_split_item.py

@@ -2,29 +2,30 @@
 #  Copyright (c) 2012, Enthought, Inc.
 #  All rights reserved.
 #------------------------------------------------------------------------------
-from .qt.QtGui import QFrame
+from .qt.QtGui import QFrame, QSplitter, QLayout
 from .q_single_widget_layout import QSingleWidgetLayout
 from .qt_container import QtContainer
 from .qt_widget import QtWidget
 
 
 class QSplitItem(QFrame):
-    """ A QFrame subclass which acts as an item QSplitter.
+    """ A QFrame subclass which acts as an item in a QSplitter.
 
     """
-    def __init__(self, *args, **kwargs):
+    def __init__(self, parent=None):
         """ Initialize a QSplitItem.
 
         Parameters
         ----------
-        *args, **kwargs
-            The position and keyword arguments required to initialize
-            a QWidget.
+        parent : QWidget, optional
+            The parent widget of the split item, or None if it has no
+            parent.
 
         """
-        super(QSplitItem, self).__init__(*args, **kwargs)
+        super(QSplitItem, self).__init__(parent)
         self._split_widget = None
         self.setLayout(QSingleWidgetLayout())
+        self.layout().setSizeConstraint(QLayout.SetMinAndMaxSize)
 
     def splitWidget(self):
         """ Get the split widget for this split item.
@@ -49,6 +50,62 @@ def setSplitWidget(self, widget):
         self._split_widget = widget
         self.layout().setWidget(widget)
 
+    def stretch(self):
+        """ Get the stretch factor for this split item.
+
+        Returns
+        -------
+        result : int
+            The stretch factor for this split item.
+
+        """
+        # horizontal and vertical stretch are set to be the same,
+        # so which one is returned here is irrelevant.
+        return self.sizePolicy().horizontalStretch()
+
+    def setStretch(self, stretch):
+        """ Set the stretch factor for this split item.
+
+        Parameters
+        ----------
+        stretch : int
+            The stretch factor to use for this split item.
+
+        """
+        stretch = max(0, stretch)
+        policy = self.sizePolicy()
+        policy.setHorizontalStretch(stretch)
+        policy.setVerticalStretch(stretch)
+        self.setSizePolicy(policy)
+
+    def collapsible(self):
+        """ Get whether or not this widget is collapsible.
+
+        Returns
+        -------
+        result : bool
+            Whether or not this item can be collapsed to zero size.
+
+        """
+        parent = self.parentWidget()
+        if isinstance(parent, QSplitter):
+            return parent.isCollapsible(parent.indexOf(self))
+        return False
+
+    def setCollapsible(self, collapsible):
+        """ Set whether or not this widget is collapsible.
+
+        Parameters
+        ----------
+        collapsible : bool
+            Whether or not this item can be collapsed to zero size.
+            This holds regardless of the minimum size of the item.
+
+        """
+        parent = self.parentWidget()
+        if isinstance(parent, QSplitter):
+            return parent.setCollapsible(parent.indexOf(self), collapsible)
+
 
 class QtSplitItem(QtWidget):
     """ A Qt implementation of an Enaml SplitItem.
@@ -68,7 +125,8 @@ def create(self, tree):
 
         """
         super(QtSplitItem, self).create(tree)
-        self.set_preferred_size(tree['preferred_size'])
+        self.set_stretch(tree['stretch'])
+        self.set_collapsible(tree['collapsible'])
 
     def init_layout(self):
         """ Initialize the layout for the underyling widget.
@@ -116,19 +174,30 @@ def child_added(self, child):
     #--------------------------------------------------------------------------
     # Message Handlers
     #--------------------------------------------------------------------------
-    def on_action_set_preferred_size(self, content):
-        """ Handle the 'set_preferred_size' action from the Enaml widget.
+    def on_action_set_stretch(self, content):
+        """ Handle the 'set_stretch' action from the Enaml widget.
+
+        """
+        self.set_stretch(content['stretch'])
+
+    def on_action_set_collapsible(self, content):
+        """ Handle the 'set_collapsible' action from the Enaml widget.
 
         """
-        self.set_preferred_size(content['preferred_size'])
+        self.set_collapsible(content['collapsible'])
 
     #--------------------------------------------------------------------------
     # Widget Update Methods
     #--------------------------------------------------------------------------
-    def set_preferred_size(self, size):
-        """ Set the preferred size for this item in the splitter.
+    def set_stretch(self, stretch):
+        """ Set the stretch factor for the underlying widget.
+
+        """
+        self.widget().setStretch(stretch)
+
+    def set_collapsible(self, collapsible):
+        """ Set the collapsible flag for the underlying widget.
 
         """
-        # XXX implement me
-        pass
+        self.widget().setCollapsible(collapsible)
 

enaml/qt/qt_splitter.py

@@ -53,9 +53,6 @@ class QCustomSplitter(QSplitter):
     #: of the splitter is no longer valid.
     layoutRequested = Signal()
 
-    #--------------------------------------------------------------------------
-    # Public API
-    #--------------------------------------------------------------------------
     def createHandle(self):
         """ A reimplemented virtual method to create splitter handles.
 
@@ -145,7 +142,7 @@ def init_layout(self):
         # collapsed, the effect of this is to restore the order of event
         # processing.
         if sys.platform == 'win32':
-            widget.splitterMoved.connect(self.on_win32_slider_moved)
+            widget.splitterMoved.connect(self.on_win32_splitter_moved)
 
     #--------------------------------------------------------------------------
     # Child Events
@@ -173,8 +170,8 @@ def on_layout_requested(self):
         """
         self.size_hint_updated()
 
-    def on_win32_slider_moved(self):
-        """ Handle the 'sliderMoved' signal from the QSplitter.
+    def on_win32_splitter_moved(self):
+        """ Handle the 'splitterMoved' signal from the QSplitter.
 
         This handler is only connected when running on Windows and it
         serves to make sure paint events get generated during heavy
@@ -217,20 +214,3 @@ def set_live_drag(self, live_drag):
         """
         self.widget().setOpaqueResize(live_drag)
 
-    # def set_preferred_sizes(self, sizes):
-    #     """ Set the preferred sizes for the children.
-
-    #     For sizes not supplied by the user, either via None values or
-    #     a list which is too short, the current size for that element
-    #     will be used in its place.
-
-    #     """
-    #     widget = self.widget()
-    #     curr_sizes = widget.sizes()[:]
-    #     max_idx = min(len(curr_sizes), len(sizes))
-    #     for idx in xrange(max_idx):
-    #         size = sizes[idx]
-    #         if size is not None:
-    #             curr_sizes[idx] = size
-    #     widget.setSizes(curr_sizes)
-

enaml/widgets/split_item.py

@@ -2,7 +2,7 @@
 #  Copyright (c) 2012, Enthought, Inc.
 #  All rights reserved.
 #------------------------------------------------------------------------------
-from traits.api import Either, Int, Property, cached_property
+from traits.api import Any, Bool, Range, Property, cached_property
 
 from .container import Container
 from .widget import Widget
@@ -16,13 +16,21 @@ class SplitItem(Widget):
     instance of Container.
 
     """
-    #: The preferred size for this item in the splitter, or None if
-    #: there is no preference for the size. The default is None.
-    preferred_size = Either(None, Int)
+    #: The stretch factor for this item. The stretch factor determines
+    #: how much an item is resized relative to its neighbors when the
+    #: splitter space is allocated.
+    stretch = Range(low=0, value=1)
+
+    #: Whether or not the item can be collapsed to zero width by the
+    #: user. This holds regardless of the minimum size of the item.
+    collapsible = Bool(True)
 
     #: A read only property which returns the split widget.
     split_widget = Property(depends_on='children')
 
+    #: This is a deprecated attribute. It should no longer be used.
+    preferred_size = Any
+
     #--------------------------------------------------------------------------
     # Initialization
     #--------------------------------------------------------------------------
@@ -31,15 +39,16 @@ def snapshot(self):
 
         """
         snap = super(SplitItem, self).snapshot()
-        snap['preferred_size'] = self.preferred_size
+        snap['stretch'] = self.stretch
+        snap['collapsible'] = self.collapsible
         return snap
 
     def bind(self):
         """ Bind the change handlers for the widget.
 
         """
         super(SplitItem, self).bind()
-        self.publish_attributes('preferred_size')
+        self.publish_attributes('stretch', 'collapsible')
 
     #--------------------------------------------------------------------------
     # Private API