Working on a new SelectionHelper. The current one is too complex to maintain. Another *planned* change: ChildrenHelper will perform more of the operations, the subclasses will only have the right to "accept" or "reject" operations.

Author: FremyCompany_cp

FC.MathEditor/WpfMathEditor/Classes/ChildrenHelper.vb

@@ -42,9 +42,10 @@
 
             This.StartBatchProcess()
 
+            Dim Index = Count + 1
             This.Attach(NewChild)
             Add_Internal(NewChild)
-            This.RaiseChildAdded(NewChild)
+            This.RaiseChildAdded(NewChild, Index)
 
             This.RaiseChanged()
 
@@ -68,8 +69,9 @@
 
             This.StartBatchProcess()
 
+            Dim Index = IndexOf(OldChild)
             Remove_Internal(OldChild)
-            This.RaiseChildRemoved(OldChild)
+            This.RaiseChildRemoved(OldChild, Index)
             This.Detach(OldChild)
             This.RaiseChanged()
 
@@ -91,9 +93,10 @@
 
             This.StartBatchProcess()
 
+            Dim Index = IndexOf(OldChild) + 1
             This.Attach(NewChild)
             InsertAfter_Internal(NewChild, OldChild)
-            This.RaiseChildAdded(NewChild)
+            This.RaiseChildAdded(NewChild, Index)
             This.RaiseChanged()
 
 

FC.MathEditor/WpfMathEditor/Classes/MathElement.XmlTree.vb

@@ -306,7 +306,14 @@ Partial Public MustInherit Class MathElement
         If _Parent IsNot Nothing Then Parent.RaiseChanged()
     End Sub
 
-    ' TODO: RemovedFromParent
+    ' TODO: Reviewing completely the event usage (drawing a schema)
+
+    Public Event SubTreeModified As EventHandler(Of TreeEventArgs)
+    Public Sub RaiseSubTreeModified(ByVal e As TreeEventArgs)
+        RaiseEvent SubTreeModified(Me, e)
+        RaiseEvent Changed(Me, EventArgs.Empty)
+    End Sub
+
     Public Event AttachedToParent As EventHandler
     Public Sub RaiseAttachedToParent()
         RaiseEvent AttachedToParent(Me, EventArgs.Empty)
@@ -333,28 +340,45 @@ Partial Public MustInherit Class MathElement
     End Sub
 
     Public Event ChildAdded As EventHandler(Of TreeEventArgs)
-    Public Sub RaiseChildAdded(ByVal Child As MathElement)
-        RaiseEvent ChildAdded(Me, New TreeEventArgs(Child))
+    Public Sub RaiseChildAdded(ByVal ChildElement As MathElement, ByVal ChildIndex As Integer)
+        Dim e = New TreeEventArgs(ChildElement, Me, ChildIndex, TreeEventArgs.TreeAction.Added)
+        RaiseEvent ChildAdded(Me, e)
+        RaiseEvent SubTreeModified(Me, e)
     End Sub
 
     Public Event ChildRemoved As EventHandler(Of TreeEventArgs)
-    Public Sub RaiseChildRemoved(ByVal Child As MathElement)
-        RaiseEvent ChildRemoved(Me, New TreeEventArgs(Child))
+    Public Sub RaiseChildRemoved(ByVal ChildElement As MathElement, ByVal ChildIndex As Integer)
+        Dim e = New TreeEventArgs(ChildElement, Me, ChildIndex, TreeEventArgs.TreeAction.Removed)
+        RaiseEvent ChildRemoved(Me, e)
+        RaiseEvent SubTreeModified(Me, e)
     End Sub
 
     Public Class TreeEventArgs : Inherits EventArgs
-        Public Property Argument As MathElement
-        Public Sub New(ByVal Argument As MathElement)
-            Me.Argument = Argument
+
+        Public Property ParentElement As MathElement
+        Public Property ChildElement As MathElement
+        Public Property ChildIndex As Integer
+        Public Property Action As TreeAction
+
+        Public Enum TreeAction
+            Added = +1 : Removed = -1 : Modified = 0
+        End Enum
+
+        Public Sub New(ByVal ChildElement As MathElement, ByVal ParentElement As MathElement, ByVal ChildIndex As Integer, ByVal Action As TreeAction)
+            Me.ChildElement = ChildElement
+            Me.ParentElement = ParentElement
+            Me.ChildIndex = ChildIndex
+            Me.Action = Action
         End Sub
+
     End Class
 
     Private Sub MathElement_ChildAdded(ByVal sender As Object, ByVal e As TreeEventArgs) Handles Me.ChildAdded
-        e.Argument.RaiseAddedToParent()
+        e.ChildElement.RaiseAddedToParent()
     End Sub
 
     Private Sub MathElement_ChildRemoved(ByVal sender As Object, ByVal e As TreeEventArgs) Handles Me.ChildRemoved
-        e.Argument.RaiseRemovedFromParent()
+        e.ChildElement.RaiseRemovedFromParent()
     End Sub
 
     Private Sub MathElement_DetachedFromDocument(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.DetachedFromDocument
@@ -368,4 +392,8 @@ Partial Public MustInherit Class MathElement
             Child.RaiseDetachedFromDocument()
         Next
     End Sub
+
+    Private Sub MathElement_SubTreeModified(ByVal sender As Object, ByVal e As TreeEventArgs) Handles Me.SubTreeModified
+        Me.Parent.RaiseSubTreeModified(e)
+    End Sub
 End Class

FC.MathEditor/WpfMathEditor/Classes/SelectionHelper.Actions.vb

@@ -21,6 +21,16 @@
         End Get
     End Property
 
+    Public Sub CollapseToEnd()
+        Dim NewPoint = New Selection(EndPoint.CommonAncestror, EndPoint.CommonAncestror.Children.Before(EndPoint.SelectionStart), EndPoint.SelectionStart)
+        SetSelection(NewPoint, PointToChange:=SelectionHelper.SelectionPointType.StartPoint)
+    End Sub
+
+    Public Sub CollapseToStart()
+        ' TODO: Implement CollapseToStart
+        Throw New NotImplementedException()
+    End Sub
+
     Public Sub MoveNext(Optional ByVal MovedPoint As SelectionPointType = SelectionPointType.Selection)
         Dim Sel As Selection = GetSelection(MovedPoint)
         Dim E = Sel.CommonAncestror.ParentLayoutEngineChild

FC.MathEditor/WpfMathEditor/Classes/SelectionHelper.vb

@@ -1,10 +1,12 @@
 Partial Public Class SelectionHelper
     Implements IEnumerable(Of MathElement)
 
-    Private This As MathDocument
+    Protected This As MathDocument
+    Private WithEvents CA_SEL, CA_START, CA_END As MathElement
+
     Public Sub New(ByVal This As MathDocument)
         Me.This = This
-        SetSelection(This, Nothing, Nothing)
+        SetSelection(This, This.LastChild, Nothing)
     End Sub
 
     Private IsSelectionChanging As Boolean
@@ -43,41 +45,51 @@
     Private Sub SetSelection(ByVal StartPoint As Selection, ByVal EndPoint As Selection)
 
         ' Compute _Selection
-        Dim CA = StartPoint.SelectionStart.GetCommonAncestrorWith(EndPoint.SelectionEnd)
         Dim SS = StartPoint.SelectionStart
-        Dim SE = StartPoint.SelectionEnd
+        Dim SE = EndPoint.SelectionEnd
+
+        ' Collapse selection points
+        StartPoint = New Selection(StartPoint.CommonAncestror, SS, StartPoint.CommonAncestror.Children.After(SS))
+        EndPoint = New Selection(EndPoint.CommonAncestror, EndPoint.CommonAncestror.Children.After(SE), SE)
+
+        Dim CA = If(SS, SE)
+        If StartPoint.CommonAncestror Is EndPoint.CommonAncestror Then
+            CA = StartPoint.CommonAncestror
+        Else
+            CA = StartPoint.CommonAncestror.GetCommonAncestrorWith(EndPoint.CommonAncestror)
 
-        While SS.Parent IsNot CA
-            SS = SS.Parent
-        End While
+            While SS.Parent IsNot CA
+                SS = SS.Parent
+            End While
 
-        While SE.Parent IsNot SE
-            SE = SE.Parent
-        End While
+            While SE.Parent IsNot SE
+                SE = SE.Parent
+            End While
 
-        ' Insert StartPoint and EndPoint if needed
-        Dim Dir = SelectionDirection.LTR
+        End If
 
-        If SE.IsBefore(SS) Then
+        ' Invert StartPoint and EndPoint if needed
+        Dim Dir As SelectionDirection = SelectionDirection.LTR
+        If (SE IsNot Nothing) AndAlso (SS IsNot Nothing) AndAlso (SE Is SS OrElse SE.IsBefore(SS)) Then
             Dir = SelectionDirection.RTL
-            Dim Temp = StartPoint
-            StartPoint = EndPoint
-            EndPoint = Temp
+            Dim ST = SE.PreviousSibling
+            SE = SS.NextSibling : SS = ST
         End If
 
         ' Set the selection
         SetSelection_Internal(New Selection(CA, SS, SE), StartPoint, EndPoint)
+        _Dir = Dir
 
     End Sub
 
-    Public Sub SetSelection(ByVal Point As Selection, Optional ByVal PointToChange As SelectionPointType = SelectionPointType.Selection)
+    Public Sub SetSelection(ByVal NewPoint As Selection, Optional ByVal PointToChange As SelectionPointType = SelectionPointType.Selection)
         Select Case PointToChange
             Case SelectionPointType.Selection
-                SetSelection(Point.CommonAncestror, Point.SelectionStart, Point.SelectionEnd)
+                SetSelection(NewPoint.CommonAncestror, NewPoint.SelectionStart, NewPoint.SelectionEnd)
             Case SelectionPointType.StartPoint
-                SetSelection(Point, EndPoint)
+                SetSelection(NewPoint, EndPoint)
             Case SelectionPointType.EndPoint
-                SetSelection(StartPoint, Point)
+                SetSelection(StartPoint, NewPoint)
             Case Else
                 Throw New ArgumentException("Unknown value for the selection point type", "PointToChange")
         End Select
@@ -97,20 +109,39 @@
     End Function
 
     Public Sub SetSelection(ByVal CommonAncestror As MathElement, ByVal SelectionStart As MathElement, ByVal SelectionEnd As MathElement)
+
         ' Check if the selection is valid
         If (
-            (CommonAncestror.ParentDocument Is This) _
+            (CommonAncestror IsNot Nothing) _
+            AndAlso (CommonAncestror.ParentDocument Is This) _
             AndAlso (SelectionStart Is Nothing OrElse SelectionStart.Parent Is CommonAncestror) _
             AndAlso (SelectionEnd Is Nothing OrElse SelectionEnd.Parent Is CommonAncestror)
         ) Then
 
+            ' Invert StartPoint and EndPoint if needed
+            Dim SS = SelectionStart, SE = SelectionEnd, CA = CommonAncestror
+            If (SS Is Nothing) OrElse (SE IsNot Nothing AndAlso (SE Is SS OrElse SE.IsBefore(SS))) Then
+                _Dir = SelectionDirection.RTL
+                Dim ST = If(SE Is Nothing, Nothing, SE.PreviousSibling)
+                SE = SS : SS = SE
+            Else
+                _Dir = SelectionDirection.LTR
+            End If
+
+            ' Perform the selection change
             SetSelection_Internal(
-                New Selection(CommonAncestror, SelectionStart, SelectionEnd),
-                New Selection(CommonAncestror, SelectionStart, CommonAncestror.Children.After(SelectionStart)),
-                New Selection(CommonAncestror, CommonAncestror.Children.Before(SelectionEnd), SelectionEnd)
+                New Selection(CA, SS, SE),
+                New Selection(CA, SS, CA.Children.After(SS)),
+                New Selection(CA, CA.Children.Before(SE), SE)
             )
 
+        Else
+
+            ' Notify of an error
+            Throw New ArgumentException("Selection was invalid.")
+
         End If
+
     End Sub
 
     Private Sub SetSelection_Internal(ByVal Selection As Selection, ByVal StartPoint As Selection, ByVal EndPoint As Selection)
@@ -122,11 +153,13 @@
             Selection.SelectionStart = Temp
             _Dir = SelectionDirection.RTL
         Else
+            ' TODO: Some SetSelection perfor the _Dir modification themselves...
             _Dir = SelectionDirection.LTR
         End If
 
         ' Raise the BeforeSelectionChanged event
         If Not IsSelectionChanging Then
+            ' TODO: What about IsSelectionChanging and SelectionChanged ????
             RaiseEvent BeforeSelectionChanged(Me, EventArgs.Empty)
         End If
 
@@ -135,6 +168,10 @@
         _StartPoint = StartPoint
         _EndPoint = EndPoint
 
+        CA_START = StartPoint.CommonAncestror
+        CA_END = EndPoint.CommonAncestror
+        CA_SEL = Selection.CommonAncestror
+
     End Sub
 
     Public Sub ReverseSelection()
@@ -214,4 +251,54 @@
     Private Function GetGenericEnumerator() As System.Collections.IEnumerator Implements System.Collections.IEnumerable.GetEnumerator
         Return GetEnumerator()
     End Function
+
+    Private Sub CA_END_ChildAdded(ByVal sender As Object, ByVal e As MathElement.TreeEventArgs) Handles CA_END.ChildAdded
+        If EndPoint.SelectionEnd Is Nothing Then
+            SetSelection(New Selection(CA_END, CA_END.LastChild, Nothing), PointToChange:=SelectionPointType.EndPoint)
+        Else
+            SetSelection(New Selection(CA_END, CA_END.Children.Before(_EndPoint.SelectionEnd), _EndPoint.SelectionEnd), PointToChange:=SelectionPointType.EndPoint)
+        End If
+    End Sub
+
+    Private Sub CA_END_ChildRemoved(ByVal sender As Object, ByVal e As MathElement.TreeEventArgs) Handles CA_END.ChildRemoved
+
+        '
+        ' Verify that the newly removed child don't make the Selection EndPoint invalid!
+        '
+        If (_EndPoint.SelectionEnd Is Nothing) OrElse (CA_END.Children.Contains(_EndPoint.SelectionEnd)) Then
+            SetSelection(New Selection(CA_END, CA_END.Children.Before(_EndPoint.SelectionEnd), _EndPoint.SelectionEnd), PointToChange:=SelectionPointType.EndPoint)
+        Else
+            If (_EndPoint.SelectionStart Is Nothing) OrElse (CA_END.Children.Contains(_EndPoint.SelectionStart)) Then
+                SetSelection(New Selection(CA_END, _EndPoint.SelectionStart, CA_END.Children.After(_EndPoint.SelectionStart)), PointToChange:=SelectionPointType.EndPoint)
+            Else
+                SetSelection(New Selection(CA_END, CA_END.LastChild, Nothing), PointToChange:=SelectionPointType.EndPoint)
+            End If
+        End If
+
+    End Sub
+
+    Private Sub CA_START_ChildAdded(ByVal sender As Object, ByVal e As MathElement.TreeEventArgs) Handles CA_START.ChildAdded
+        If StartPoint.SelectionStart Is Nothing Then
+            SetSelection(New Selection(CA_START, Nothing, CA_START.FirstChild), PointToChange:=SelectionPointType.StartPoint)
+        Else
+            SetSelection(New Selection(CA_START, _StartPoint.SelectionStart, CA_START.Children.After(_StartPoint.SelectionStart)), PointToChange:=SelectionPointType.StartPoint)
+        End If
+    End Sub
+
+    Private Sub CA_START_ChildRemoved(ByVal sender As Object, ByVal e As MathElement.TreeEventArgs) Handles CA_START.ChildRemoved
+
+        '
+        ' Verify that the newly removed child don't make the Selection StartPoint invalid!
+        '
+        If (_StartPoint.SelectionStart Is Nothing) OrElse (CA_START.Children.Contains(_StartPoint.SelectionStart)) Then
+            SetSelection(New Selection(CA_START, _StartPoint.SelectionStart, CA_START.Children.After(_StartPoint.SelectionStart)), PointToChange:=SelectionPointType.StartPoint)
+        Else
+            If (_StartPoint.SelectionEnd Is Nothing) OrElse (CA_END.Children.Contains(_StartPoint.SelectionEnd)) Then
+                SetSelection(New Selection(CA_START, CA_START.Children.Before(_StartPoint.SelectionEnd), _StartPoint.SelectionEnd), PointToChange:=SelectionPointType.StartPoint)
+            Else
+                SetSelection(New Selection(CA_END, CA_END.LastChild, Nothing), PointToChange:=SelectionPointType.StartPoint)
+            End If
+        End If
+
+    End Sub
 End Class