make PopupView bg transparency configurable

enaml/qt/q_popup_view.py

@@ -10,16 +10,16 @@
     pyqtSignal
 )
 from PyQt4.QtGui import (
-    QApplication, QFrame, QLayout, QPainter, QPainterPath, QRegion, QPen
+    QApplication, QWidget, QLayout, QPainter, QPainterPath, QRegion, QPen
 )
 
 from atom.api import Atom, Typed, Float, Int
 
 from .q_single_widget_layout import QSingleWidgetLayout
 
 
-class QPopupView(QFrame):
-    """ A custom QFrame which implements a framless popup widget.
+class QPopupView(QWidget):
+    """ A custom QWidget which implements a framless popup widget.
 
     It is useful for showing transient configuration dialogs as well
     as temporary notification windows.
@@ -115,7 +115,6 @@ def __init__(self, parent=None, flags=Qt.Popup):
         """
         super(QPopupView, self).__init__(parent)
         self.setWindowFlags(flags | Qt.FramelessWindowHint)
-        self.setAttribute(Qt.WA_TranslucentBackground)
         self.setAttribute(Qt.WA_DeleteOnClose)
         layout = QSingleWidgetLayout()
         layout.setSizeConstraint(QLayout.SetMinAndMaxSize)
@@ -473,7 +472,6 @@ def paintEvent(self, event):
         """ Handle the paint event for the popup view.
 
         """
-        super(QPopupView, self).paintEvent(event)
         palette = self.palette()
         fill_color = palette.window().color()
         stroke_color = palette.windowText().color()

enaml/qt/qt_popup_view.py

@@ -43,8 +43,11 @@ def create_widget(self):
         """ Create the QPopupView widget.
 
         """
-        flags = WINDOW_TYPES[self.declaration.window_type]
+        d = self.declaration
+        flags = WINDOW_TYPES[d.window_type]
         self.widget = QPopupView(self.parent_widget(), flags)
+        if d.translucent_background:
+            self.widget.setAttribute(Qt.WA_TranslucentBackground)
 
     def init_widget(self):
         """ Initialize the widget.

enaml/widgets/popup_view.py

@@ -6,7 +6,8 @@
 # The full license is in the file COPYING.txt, distributed with this software.
 #------------------------------------------------------------------------------
 from atom.api import (
-    Coerced, Enum, Float, Event, Int, Typed, ForwardTyped, observe, set_default
+    Bool, Coerced, Enum, Float, Event, Int, Typed, ForwardTyped, observe,
+    set_default
 )
 
 from enaml.application import deferred_call
@@ -142,6 +143,13 @@ class PopupView(Widget):
     #: or equal to zero means no fade.
     fade_out_duration = d_(Int(100))
 
+    #: Whether or not the background of the popup view is translucent.
+    #: This must be True in order to use background colors with alpha
+    #: and for the fade in and out animation to have effect. This value
+    #: must be set before the popup view is shown. Changes to this value
+    #: after the popup is shown will have no effect.
+    translucent_background = d_(Bool(True))
+
     #: An event emitted when the view is closed. After this event is
     #: fired, the view will be destroyed and should not be used.
     closed = d_(Event(), writable=False)