use wx.Accessible to improve accessibility of our settings panels and checkable list controls

source/gui/nvdaControls.py

@@ -9,7 +9,6 @@
 import wx
 from comtypes import GUID
 from wx.lib.mixins import listctrl as listmix
-from . import accPropServer
 from .dpiScalingHelper import DpiScalingHelperMixin
 from . import guiHelper
 import oleacc
@@ -86,85 +85,35 @@ def OnSetFocus(self, evt):
 		self.SetSelection(0, numChars)
 		evt.Skip()
 
-class AccPropertyOverride(accPropServer.IAccPropServer_Impl):
 
-	def __init__(self, control, propertyAnnotations):
-		"""
-		A simple class for overriding specific values on a control
-		:type propertyAnnotations: dict
-		"""
-		super(AccPropertyOverride, self).__init__(
-			control,
-			annotateProperties=list(propertyAnnotations.keys()),
-			annotateChildren=False
-		)
-		self.propertyAnnotations = propertyAnnotations
+class ListCtrlAccessible(wx.Accessible):
+	"""WX Accessible implementation for checkable lists which aren't fully accessible."""
 
-	def _getPropValue(self, pIDString, dwIDStringLen, idProp):
-		control = self.control()  # self.control held as a weak ref, ensure it stays alive for the duration of this method
-		if control is None or not self.propertyAnnotations:
-			return None
+	def GetRole(self, childId):
+		if childId == winUser.CHILDID_SELF:
+			return super().GetRole(childId)
+		return (wx.ACC_OK, wx.ROLE_SYSTEM_CHECKBUTTON)
 
-		try:
-			val = self.propertyAnnotations[idProp]
-			if callable(val):
-				val = val()
-			return self._hasProp(val)
-		except KeyError:
-			pass
-
-		return None
-
-	def _cleanup(self):
-		# could contain references (via lambda) of our owner, set it to None to avoid a circular reference which
-		# would block destruction.
-		self.propertyAnnotations = None
-		super(AccPropertyOverride, self)._cleanup()
-
-class ListCtrlAccPropServer(accPropServer.IAccPropServer_Impl):
-	"""AccPropServer for wx checkable lists which aren't fully accessible."""
-
-	def __init__(self, control):
-		super(ListCtrlAccPropServer, self).__init__(
-			control,
-			annotateProperties=[
-				oleacc.PROPID_ACC_ROLE,  # supposed to be checkbox, rather than list item
-				oleacc.PROPID_ACC_STATE  # should include the checkable state and checked state if the item is checked.
-			],
-			annotateChildren=True
-		)
+	def GetState(self, childId):
+		if childId == winUser.CHILDID_SELF:
+			return super().GetState(childId)
+		states = wx.ACC_STATE_SYSTEM_SELECTABLE | wx.ACC_STATE_SYSTEM_FOCUSABLE
+		if self.Window.IsChecked(childId - 1):
+			states |= wx.ACC_STATE_SYSTEM_CHECKED
+		if self.Window.IsSelected(childId - 1):
+			# wx doesn't seem to  have a method to check whether a list item is focused.
+			# Therefore, assume that a selected item is focused,which is the case in single select list boxes.
+			states |= wx.ACC_STATE_SYSTEM_SELECTED | wx.ACC_STATE_SYSTEM_FOCUSED
+		return (wx.ACC_OK, states)
 
-	def _getPropValue(self, pIDString: str, dwIDStringLen: int, idProp: GUID) -> Optional[Tuple[BOOL, Any]]:
-		control = self.control()  # self.control held as a weak ref, ensure it stays alive for the duration of this method
-		if control is None:
-			return None
-
-		# Import late to prevent circular import.
-		from IAccessibleHandler import accPropServices
-		handle, objid, childid = accPropServices.DecomposeHwndIdentityString(pIDString, dwIDStringLen)
-		if childid == winUser.CHILDID_SELF:
-			return None
-
-		if idProp == oleacc.PROPID_ACC_ROLE:
-			return self._hasProp(oleacc.ROLE_SYSTEM_CHECKBUTTON)
-
-		if idProp == oleacc.PROPID_ACC_STATE:
-			states = oleacc.STATE_SYSTEM_SELECTABLE|oleacc.STATE_SYSTEM_FOCUSABLE
-			if control.IsChecked(childid-1):
-				states |= oleacc.STATE_SYSTEM_CHECKED
-			if control.IsSelected(childid-1):
-				# wx doesn't seem to  have a method to check whether a list item is focused.
-				# Therefore, assume that a selected item is focused,which is the case in single select list boxes.
-				states |= oleacc.STATE_SYSTEM_SELECTED | oleacc.STATE_SYSTEM_FOCUSED
-			return self._hasProp(states)
 
 class CustomCheckListBox(wx.CheckListBox):
 	"""Custom checkable list to fix a11y bugs in the standard wx checkable list box."""
 
 	def __init__(self, *args, **kwargs):
 		super(CustomCheckListBox, self).__init__(*args, **kwargs)
-		# Register object with COM to fix accessibility bugs in wx.
-		self.server = ListCtrlAccPropServer(self)
+		# Register a custom wx.Accessible implementation to fix accessibility incompleties
+		self.SetAccessible(ListCtrlAccessible(self))
 		# Register ourself with ourself's selected event, so that we can notify winEvent of the state change.
 		self.Bind(wx.EVT_CHECKLISTBOX, self.notifyIAccessible)
 
@@ -189,8 +138,8 @@ def __init__(self, parent, id=wx.ID_ANY, autoSizeColumn="LAST", pos=wx.DefaultPo
 	):
 		AutoWidthColumnListCtrl.__init__(self, parent, id=id, pos=pos, size=size, style=style, autoSizeColumn=autoSizeColumn)
 		listmix.CheckListCtrlMixin.__init__(self, check_image, uncheck_image, imgsz)
-		# Register object with COM to fix accessibility bugs in wx.
-		self.server = ListCtrlAccPropServer(self)
+		# Register a custom wx.Accessible implementation to fix accessibility incompleties
+		self.SetAccessible(ListCtrlAccessible(self))
 		# Register our hook to check/uncheck items with space.
 		# Use wx.EVT_CHAR_HOOK, because EVT_LIST_KEY_DOWN isn't triggered for space.
 		self.Bind(wx.EVT_CHAR_HOOK, self.onCharHook)

source/gui/settingsDialogs.py

@@ -357,6 +357,22 @@ def _sendLayoutUpdatedEvent(self):
 		event.SetEventObject(self)
 		self.GetEventHandler().ProcessEvent(event)
 
+
+class SettingsPanelAccessible(wx.Accessible):
+	"""
+	WX Accessible implementation to set the role of a settings panel to property page,
+	as well as to set the accessible description based on the panel's description.
+	"""
+
+	Window: SettingsPanel
+
+	def GetRole(self, childId):
+		return (wx.ACC_OK, wx.ROLE_SYSTEM_PROPERTYPAGE)
+
+	def GetDescription(self, childId):
+		return (wx.ACC_OK, self.Window.panelDescription)
+
+
 class MultiCategorySettingsDialog(SettingsDialog):
 	"""A settings dialog with multiple settings categories.
 	A multi category settings dialog consists of a list view with settings categories on the left side, 
@@ -524,14 +540,7 @@ def _getCategoryPanel(self, catId):
 					).format(cls, panel.Size[0])
 				)
 			panel.SetLabel(panel.title)
-			import oleacc
-			panel.server = nvdaControls.AccPropertyOverride(
-				panel,
-				propertyAnnotations={
-					oleacc.PROPID_ACC_ROLE: oleacc.ROLE_SYSTEM_PROPERTYPAGE,  # change the role from pane to property page
-					oleacc.PROPID_ACC_DESCRIPTION: panel.panelDescription,  # set a description
-				}
-			)
+			panel.SetAccessible(SettingsPanelAccessible(panel))
 		return panel
 
 	def postInit(self):

user_docs/en/changes.t2t

@@ -90,6 +90,7 @@ What's New in NVDA
 - `speech.re_last_pause` has been removed - please use `speech.SpeechWithoutPauses.re_last_pause` instead. (#12195)
 - `WelcomeDialog`, `LauncherDialog` and `AskAllowUsageStatsDialog` are moved to the `gui.startupDialogs`. (#12105)
 - `getDocFilePath` has been moved from `gui` to the `documentationUtils` module. (#12105)
+- The gui.accPropServer module as well as the AccPropertyOverride and ListCtrlAccPropServer classes from the gui.nvdaControls module have been removed in favor of WX' native support for overriding accessibility properties. When enhancing accessibility of WX controls, implement wx.Accessible instead. (#12215)
 
 
 = 2020.4 =