Option Explicit
DefInt A-Z
Const BUG = False


'The Relate component module is used like a stretch control to maintain
'the relationship between controls on a form as the user resizes it.
'Except, the Relate component is much better.
'   Call AddChild(ChildControl, Move&Size)
'   Call AddContents(ContentsControl, Move&Size, ContainerControl)
'   Call AddPane(PaneControl, Move&Size, SashControl)
    Global Const RE_LEFT = 1
    Global Const RE_WIDTH = 2
    Global Const RE_TOP = 4
    Global Const RE_HEIGHT = 8
'   Call EnforceForm(Me)
'   Call EnforceContainer(ContainerControl)
'   Call EnforceSash(SashControl)
'   Call RemoveForm(Me)
'   Call RemoveControl(Text1)
    Global CorrectionX As Long
    Global CorrectionY As Long
    Global RepositionMessage As String

'HOW TO USE
'1 - Define the relationships of objects
'---------------------------------------
'This is done by calling the AddChild, AddContents,
'and AddPane methods from the Form_Load event.
'In each relationship, the movement of one object
'is expected to effect the size and position of the other.
'This is referred to as a parent/child relationship.
'Examples are provided below.
'Step 2 shows how to enforce these relationships.

'AddChild
'   Adds to the list a control and its
'   relationship to the form that can be enforced.
'   Syntax
'       Call AddChild(ChildControl, Move&Size)
'   ChildControl - The control whose relationship to the form can be enforced.
'       This control must have Left, Top, Width, and Height properties.
'   Move&Size - Integer representing the size and
'       position properties of ChildControl that
'       should move when the relationship is enforced.
'       See the Move&Size constants listed below.
'   NOTES: This relationship is enforced using the EnforceForm method.
'       The form is gotten from the ChildControl.Parent property.
'       Size and position constants for the same direction
'       should not be combined in the Move&Size argument.

'AddContents
'   Adds to the list the ContentsControl contained
'   in the ContainerControl and its relationship to
'   the ContainerControl that can be enforced.
'   Syntax
'       Call AddContents(ContentsControl, Move&Size, ContainerControl)
'   ContentsControl - The control whose relationship
'       to the ContainerControl can be enforced.
'       This control must have Left, Top, Width, and Height properties.
'   Move&Size - Integer representing the size and
'       position properties of ContentsControl that
'       should move when the relationship is enforced.
'       See the Move&Size constants listed below.
'   ContainerControl - Is often a Frame or Panel control.
'       This control must have Width, and Height properties
'       with at least read access at run-time.
'   NOTES: This relationship is enforced using the EnforceContainer method.
'       ContentsControl should be drawn inside ContainerControl.
'       Size and position constants for the same direction
'       should not be combined in the Move&Size argument.

'Move&Size Argument Constants for AddChild and AddContents
'---------------------------------------------------------------
'   RE_LEFT = 1
'       Both the left and right edges of the child
'       move with the width of the parent.
'   RE_WIDTH = 2
'       The width of the child moves
'       with the width of the parent.
'   RE_TOP = 4
'       Both the top and bottom of the child
'       move with the height of the parent.
'   RE_HEIGHT = 8
'       The height of the child moves
'       with the height of the parent.

'You can add vertical constants to horizontal constants.
'EXAMPLE: This example defines the relationships of
'a bitmap editor that might contain a PictureBox
'with ScrollBars along the right side and bottom.
'   Call AddChild(VScroll1, RE_LEFT + RE_HEIGHT)
'   Call AddChild(HScroll1, RE_WIDTH + RE_TOP)
'   Call AddChild(Picture1, RE_WIDTH + RE_HEIGHT)

'AddPane
'   Adds to the list the PaneControl and its relationship
'   to the ContainerControl that can be enforced.
'   Syntax
'       Call AddPane(PaneControl, Move&Size, SashControl)
'   PaneControl - The control whose relationship
'       to the SashControl can be enforced.
'       This control must have Left, Top, Width, and Height properties.
'   Move&Size - Integer representing the size and
'       position properties of PaneControl that
'       should move when the relationship is enforced.
'   RE_LEFT = 1
'       Both the left and right edges of PaneControl
'       move with the left edge of SashControl.
'   RE_WIDTH = 2
'       The width of PaneControl
'       moves with the left edge of SashControl.
'   RE_TOP = 4
'       both the top and bottom of PaneControl
'       move with the top of SashControl.
'   RE_HEIGHT = 8
'       the height of PaneControl
'       moves with the top of SashControl.
'   SashControl - Is often used as a separator
'       bar between two sides of a form.
'       This control must have Left, Top properties
'       with at least read access at run-time.
'   NOTES: This relationship is enforced using the EnforceSash method.
'       Both controls must have Left, Top, Width, and Height properties.
'       PaneControl and SashControl should have the same parent or container.
'       In other words, they should both be drawn
'       on the same form or container control.
'       Size and position constants for the same direction
'       can be combined to produce special conditions.
'       Such a PaneControl is usually to the right or below SashControl.
'       Take, for example, one ListBox control above another
'       with a SashControl between them.
'       Both the Top and Height properties of the lower
'       PaneControl must change when the SashControl is enforced.
'       Particular caution is taken by this component to make sure that the
'       bottom edge of the lower PaneControl does not snap out of place.


'2 - Maintain the relationships.
'-------------------------------
'This is done by calling the EnforceForm,
'EnforceContainer, and EnforceSash methods.
'EnforceForm is usually called from the Form_Resize event.
'EnforceContainer is usually called right after ContainerControl
'is moved which is usually caused by EnforceForm or EnforceSash.
'The order in this case is important.
'   Call EnforceForm(Me)
'   Call EnforceContainer(ContainerControl)
'EnforceSash is usually called right after SashControl.Move method is called.
'This is usually in a procedure called from various DragDrop events.
'   Call EnforceSash(SashControl)


'3 - Clean Up
'------------
'Be sure to call the RemoveControl method
'whenever a parent or child control is unloaded.
'Call the RemoveForm method from the
'Form_Unload event of parent forms.
'There's no need to call RemoveControl
'in the Form_Unload event.
'   Call RemoveForm(Me)
'   Call RemoveControl(Text1)


'4 - Movement Correction (optional)
'----------------------------------
'The user might resize a form or move a Parent
'in such a way as to make children
'distorted or unusable. It might be obvious to the user
'to move whatever back a bit. Or you might prefer to
'prevent the user from doing such a thing in the
'first place. Such movements can be corrected in two
'basic ways. In code, you can define limitations that
'you can check before calling EnforceForm, EnforceContainer, and EnforceSash.
'If the limits are exceeded, then you can programatically
'move the form or control back within the limitations.
'The second method is to use the CorrectionX and
'CorrectionY global variables.

'For example:

    'Private Sub CommonDrop(Source As Control, ByVal X As Single, ByVal Y As Single)
    '    Do
    '        CorrectionX = 0
    '        Source.Move X
    '        Call EnforceSash(Source)
    '        X = X + CorrectionX
    '    Loop Until CorrectionX = 0
    'End Sub

'   Sub Form_Resize()
'       If Me.WindowState = MINIMIZED Then Exit Sub

'       Call EnforceForm(Me)
'       If CorrectionX > 0 Or CorrectionY > 0 Then
'           'Move causes a cascading event.
'           Me.Move Me.Left, Me.Top, Me.Width + CorrectionX, Me.Height + CorrectionY
'       End If
'   End Sub

'Watch out for cascading events. If you move a form
'in the From_Resize event, the event will start a second
'time before completing the first. Exit the event right
'after calling the Move method. Note that CorrectionX and
'CorrectionY are in the ScaleMode of the parent's size
'and position properties. So, no conversion is needed.
'CorrectionX and CorrectionY can be negative
'for Splitter Bar type SashControls.
'CorrectionX and CorrectionY are set to zero by EnforceForm.
'The sign of CorrectionX and CorrectionY indicate the direction.
'For example, if CorrectionX is positive after EnforceForm,
'then widen the form more.

'NOTES
'-----
'The ScaleMode of every form and ContainerControl must be Twips or Pixels.
'If a ContainerControl does not have a ScaleMode property,
'then it's assumed to be Twips.
'If a SashControl is a lightweight/graphic control,
'then the ScaleMode of the parent form is used.
'If this component finds a situation it cannot handle,
'it puts a message in RepositionMessage.
'A error is not generated since many of these problems
'are not so bothersome to the user as to require such a measure.
'These messages are usually generated while
'testing or debugging an application.
'So, RepositionMessage can be very useful in these cases.
'If a VB error occurs in this component module,
'it can be trapped by the host/client application.
'The child controls (which are ChildControl, ContentsControl, and
'PaneControl) must have write access at run-time to Left and Top properties.
'If RE_HEIGHT option is used, then write access to
'Width and Height properties is needed at run-time.
'If RE_WIDTH  option is used, then write access
'to the Width property is needed at run-time.


'*********************************************
'The rest is private!
'*********************************************
'*********************************************
'*********************************************

'THE SCALE DILEMMA
'----------------
'The user of this component might change the ScaleMode
'of the form, container, or parent. therefore,
'this component must keep track of these ScaleModes
'each time this component is used.

'In the case of Frame methods, not all container
'controls have a ScaleMode property.
'If one does not, the ScaleMode of the size and
'position properties of controls in the container
'are usually (and assumed to be) in TWIPS.
'However, The size and position properties of
'the container itself are not expressed according to the
'container's ScaleMode. Instead, they are based on
'the ScaleMode of the container's parent (which might
'not be the form). Since all containers have an hWnd
'property, the true parent can be found using the
'GetParent API call (not the Parent property).

'If MasterControls are allowed to be lightweight/graphic
'controls, then a MasterControl might not have an
'hWnd property. In this case, GetParent can't be used.
'In addition, there is no way to restrict the user from
'changing the ScaleMode of the true parent. Therefore,
'the user must be warned about this situation.

'ANCHOR DILEMMA
'--------------

'CORRECTION DIRECTION DILEMMA
'----------------------------
'For parent forms and containers,
'a positive correction amount means the parent should be enlarged.
'But if a sash is moved and there is a correction to be performed,
'can the sign of the correction amount indicate the direction?
'EnforceSash could determine if the pane that
'needs more room is above or below the sash.
'If the pane is below, make the correction negative.
'But what if the pane is a container that is also enforced?
'EnforceContainer does not know what made it smaller.
'Therefore, it does not know whenter to
'make the correction negative or positive.
'For this reasion, another tactic is needed.
'It is assumed that the panes that the sash
'was moved away from, have enough room.
'Therefore, a positive correction amount
'means that the sash should be moved back.
'This means that the client side correction code needs
'to figure out which way the sash was moved.

'DOUBLE CORRECTION DILEMMA
'-------------------------
'Why is the client side correction code in a loop?
'After all the relationships have been inforced,
'the correction performed,
'and then the relationships enforced again,
'there may still be a correction to perform.
'This occures when the child in a
'relationship is the parent in another.
'In this case there is a heirarchy of controls.
'If there is no heirarchy,
'then the loop is not needed.
'An alternitive technique considers that heirarchy.
'First, the parents that are not children
'in other relationships are enforced.
'A correction is performed.
'And then its children that are parents to
'other controls are enforced and so on.
'This technique might be quicker; but,
'the loop is more portible.
'Sometimes, the enforcements are never satisfied
'and the loop technique becomes endless.



    Const PARENT_FORM = 1
    Const PARENT_CONTAINER = 2
    Const PARENT_SASH = 3

    Type ReChildStruct
        Sides       As Integer
        Horizontal  As Long
        Vertical    As Long
        ParentType  As Integer
        ParentIndex As Integer
    End Type
    
    Dim mChildCount      As Integer
    Dim mChildData()     As ReChildStruct
    Dim mChildControl()  As Control

    'Parent arrays.
    Dim mFormCount  As Integer
    Dim mForm()     As Form

    Dim mControlCount As Integer
    Dim mControl()    As Control

'*********************************************
'Declarations for Scale routines. It's private!
'*********************************************
    Const TWIPS = 1
    Const PIXELS = 3
    Dim mTpux As Integer 'Twips Per Unit X
    Dim mTpuy As Integer 'Twips Per Unit Y
    'GetParent may return a frame where control.Parent always returns a form.
    Declare Function ReGetParentAPI Lib "User" Alias "GetParent" (ByVal hWnd As Integer) As Integer


    Dim d As ReChildStruct
    Dim c As Control
    Dim Sides As String

Sub AddChild (ctlChild As Control, ByVal Sides As Integer)
    Dim frmParent  As Form
    Dim ChildData  As ReChildStruct

    Set frmParent = ctlChild.Parent
    'The external scale mode of a form is always TWIPS.
    'Forms always have the ScaleMode property.
    If Not zValidateScaleMode(frmParent.ScaleMode) Then Exit Sub

    ChildData.ParentIndex = zMakeParentFormIndex(frmParent)
    ChildData.ParentType = PARENT_FORM
    Call AddContentsOrChildSub(Sides, ChildData, ctlChild, frmParent.Width, frmParent.Height)
End Sub

Sub AddContents (ctlChild As Control, ByVal Sides As Integer, ctlContainer As Control)
    Dim ChildData As ReChildStruct
    Dim Wide As Long
    Dim High As Long

    If Not zValidateScaleMode(zExternalScaleModeVB3(ctlContainer)) Then Exit Sub

    Wide = ctlContainer.Width * mTpux
    High = ctlContainer.Height * mTpuy
    If Not zValidateScaleMode(zInternalScaleMode(ctlContainer)) Then Exit Sub

    ChildData.ParentIndex = zMakeParentControlIndex(ctlContainer)
    ChildData.ParentType = PARENT_CONTAINER
    Call AddContentsOrChildSub(Sides, ChildData, ctlChild, Wide, High)
End Sub

Private Sub AddContentsOrChildSub (ByVal Sides As Integer, ChildData As ReChildStruct, ctlChild As Control, ByVal ParentWidth As Long, ByVal ParentHeight As Long)
    ChildData.Sides = Sides
    ChildData.Horizontal = ParentWidth - (ctlChild.Left + ctlChild.Width) * mTpux
    ChildData.Vertical = ParentHeight - (ctlChild.Top + ctlChild.Height) * mTpuy
    Call zAppendChild(ChildData, ctlChild)
End Sub

Sub AddPane (ctlChild As Control, ByVal Sides As Integer, ctlSash As Control)
    Dim ChildData As ReChildStruct
    Dim SashLeft      As Long
    Dim SashTop       As Long

    If Not zValidateScaleMode(zExternalScaleModeVB3(ctlSash)) Then Exit Sub

    SashLeft = ctlSash.Left * mTpux
    SashTop = ctlSash.Top * mTpuy
    ChildData.ParentIndex = zMakeParentControlIndex(ctlSash)
    ChildData.ParentType = PARENT_SASH

    '----------------------
    ChildData.Sides = Sides
    ChildData.Horizontal = SashLeft - ctlChild.Left * mTpux
    'If Sides has LEFT+WIDTH then we must leave it.
    If Not (Sides And RE_LEFT + RE_WIDTH) = RE_LEFT + RE_WIDTH Then
        ChildData.Horizontal = ChildData.Horizontal - ctlChild.Width * mTpux
    End If
    ChildData.Vertical = SashTop - ctlChild.Top * mTpuy
    'If Sides has TOP+HEIGHT then we must leave it.
    If Not (Sides And RE_TOP + RE_HEIGHT) = RE_TOP + RE_HEIGHT Then
        ChildData.Vertical = ChildData.Vertical - ctlChild.Height * mTpuy
    End If
    Call zAppendChild(ChildData, ctlChild)
End Sub

Sub EnforceContainer (ctlContainer As Control)
    Dim ChildIndex As Integer
    Dim ParentIndexSought As Integer
    Dim ParentWidth As Long
    Dim ParentHeight As Long

    For ChildIndex = 0 To mControlCount - 1
        If mControl(ChildIndex) Is ctlContainer Then Exit For
    Next 'ChildIndex
    If ChildIndex >= mControlCount Then
        RepositionMessage = "AddContents was not called for the container control passed to EnforceContainer."
        Exit Sub
    End If

    ParentIndexSought = ChildIndex
    'Not all container controls have a ScaleMode property.
    'And not all their (true) parents do either.
    If Not zValidateScaleMode(zExternalScaleModeVB3(ctlContainer)) Then Exit Sub

    ParentWidth = ctlContainer.Width * mTpux
    ParentHeight = ctlContainer.Height * mTpuy
    If Not zValidateScaleMode(zInternalScaleMode(ctlContainer)) Then Exit Sub

    ParentWidth = ParentWidth / mTpux
    ParentHeight = ParentHeight / mTpuy
    'We found the parent. Now let's find its children.
    For ChildIndex = 0 To mChildCount - 1
        If mChildData(ChildIndex).ParentType = PARENT_CONTAINER And mChildData(ChildIndex).ParentIndex = ParentIndexSought Then
            Call EnforceParentSub(ChildIndex, ParentWidth, ParentHeight)
        End If
    Next 'ChildIndex
End Sub

Sub EnforceForm (frmParent As Form)
    Dim i As Integer
    Dim ParentIndexSought As Integer
    Dim ParentWidth As Long
    Dim ParentHeight As Long

    For i = 0 To mFormCount - 1
        If mForm(i) Is frmParent Then Exit For
    Next 'i
    If i >= mFormCount Then
        RepositionMessage = "ReFormLoad was not called for the form passed to EnforceForm."
        Exit Sub
    End If

    ParentIndexSought = i
    'The external scale mode of a form is always TWIPS.
    'Forms always have the ScaleMode property.
    If Not zValidateScaleMode(frmParent.ScaleMode) Then Exit Sub

    CorrectionX = 0
    CorrectionY = 0
    ParentWidth = frmParent.Width / mTpux
    ParentHeight = frmParent.Height / mTpuy
    'We found the parent. Now let's find its children.
    For i = 0 To mChildCount - 1
        If mChildData(i).ParentType = PARENT_FORM And mChildData(i).ParentIndex = ParentIndexSought Then
            Call EnforceParentSub(i, ParentWidth, ParentHeight)
        End If
    Next 'i
End Sub

Private Sub EnforceParentSub (ByVal ChildIndex As Integer, ByVal ParentWidth As Long, ByVal ParentHeight As Long)
    Dim ChildData As ReChildStruct
    Dim ctlChild As Control
    Dim FixX    As Long
    Dim FixY    As Long
    Dim cLeft   As Long
    Dim cTop    As Long
    Dim cWidth  As Long
    Dim cHeight As Long
    
    ChildData = mChildData(ChildIndex)
    Set ctlChild = mChildControl(ChildIndex)

    '****************************************************
    'Make child dimensions.
    'If a dimention is negative, save error in Fix and make it 0.
    '****************************************************
    cLeft = ctlChild.Left
    cWidth = ctlChild.Width
    'Horizontal = ParentWidth - (ChildLeft + ChildWidth).
    If (ChildData.Sides And RE_LEFT) = RE_LEFT Then
        'ChildLeft = ParentWidth - ChildWidth - Horizontal.
        cLeft = zSluffNeg2Fix(ParentWidth - cWidth - ChildData.Horizontal / mTpux, FixX)
    ElseIf (ChildData.Sides And RE_WIDTH) = RE_WIDTH Then
        'ChildWidth = ParentWidth - ChildLeft - Horizontal.
        cWidth = zSluffNeg2Fix(ParentWidth - cLeft - ChildData.Horizontal / mTpux, FixX)
    End If
    cTop = ctlChild.Top
    cHeight = ctlChild.Height
    'Vertical = ParentWidth - (ChildTop + ChildHeight).
    If (ChildData.Sides And RE_TOP) = RE_TOP Then
        'ChildTop = ParentHeight - ChildHeight - Vertical.
        cTop = zSluffNeg2Fix(ParentHeight - cHeight - ChildData.Vertical / mTpuy, FixY)
    ElseIf (ChildData.Sides And RE_HEIGHT) = RE_HEIGHT Then
        'ChildHeight = ParentHeight - ChildTop - Vertical.
        cHeight = zSluffNeg2Fix(ParentHeight - cTop - ChildData.Vertical / mTpuy, FixY)
    End If

    '****************************************************
    'Move child.
    '****************************************************
    If (ChildData.Sides And RE_HEIGHT) = RE_HEIGHT Then
        ctlChild.Move cLeft, cTop, cWidth, cHeight
    ElseIf (ChildData.Sides And RE_WIDTH) = RE_WIDTH Then
        ctlChild.Move cLeft, cTop, cWidth
    Else
        ctlChild.Move cLeft, cTop
    End If

    '****************************************************
    'It might have snapped back a bit if squished too much.
    '****************************************************
    If (ChildData.Sides And RE_WIDTH) = RE_WIDTH Then
        FixX = FixX + ctlChild.Width - cWidth
    End If
    If (ChildData.Sides And RE_HEIGHT) = RE_HEIGHT Then
        FixY = FixY + ctlChild.Height - cHeight
    End If

    '****************************************************
    'Is this correction larger?
    '****************************************************
    'Debug.Print "EnforceParentSub " & ChildIndex & " FixY(<>0)=" & FixY & "; CorrectionY=" & CorrectionY
    If Abs(CorrectionX) < Abs(FixX) Then
        CorrectionX = FixX
    End If
    If Abs(CorrectionY) < Abs(FixY) Then
        CorrectionY = FixY
    End If
End Sub

Sub EnforceSash (ctlSash As Control)
    Dim i As Integer
    Dim ParentIndexSought As Integer
    Dim SashLeft As Long
    Dim SashTop As Long
            
    For i = 0 To mControlCount - 1
        If mControl(i) Is ctlSash Then Exit For
    Next 'i
    If i >= mControlCount Then
        RepositionMessage = "RePosLoad was not called for the sash control passed to EnforceSash."
        Exit Sub
    End If
    
    ParentIndexSought = i
    'If ctlSash or its (true) parent are a graphic control,
    'then ScaleMode is not available. So fake it.
    If Not zValidateScaleMode(zExternalScaleModeVB3(ctlSash)) Then Exit Sub

    SashLeft = ctlSash.Left
    SashTop = ctlSash.Top
    'We found the parent. Now let's find its children.
    For i = 0 To mChildCount - 1
        If mChildData(i).ParentType = PARENT_SASH And mChildData(i).ParentIndex = ParentIndexSought Then
            Call EnforceSashSub(i, SashLeft, SashTop)
        End If
    Next 'i
End Sub

Private Sub EnforceSashSub (ByVal ChildIndex As Integer, ByVal SashLeft As Long, ByVal SashTop As Long)
    Dim ChildData As ReChildStruct
    Dim ctlChild As Control
    Dim FixX    As Long
    Dim FixY    As Long
    Dim cLeft   As Long
    Dim cWidth  As Long
    Dim cTop    As Long
    Dim cHeight As Long
    'An anchor is used when both the size and dimention are changed.
    'A negitive AnchorCorrection means the sash was moved too far to the right or bottom.
    Dim RightAnchor As Long
    Dim BottomAnchor As Long
    Dim AnchorCorrection As Long
    Dim IsMoveAgain As Integer
        
    ChildData = mChildData(ChildIndex)
    Set ctlChild = mChildControl(ChildIndex)

    '****************************************************
    'Make child dimensions.
    'If a dimention is negative, save error in Fix and make it 0.
    '****************************************************
    cLeft = ctlChild.Left
    cWidth = ctlChild.Width
    If (ChildData.Sides And RE_LEFT + RE_WIDTH) = RE_LEFT + RE_WIDTH Then
        'Horizontal = ParentLeft - ChildLeft
        'RightAnchor = ChildLeft + ChildWidth
        'ChildLeft = ParentLeft - Horizontal
        'ChildWidth = RightAnchor - ChildLeft
        RightAnchor = cLeft + cWidth
        'If cLeft is negative, add it to FixX.
        cLeft = zSluffNeg2Fix(SashLeft - ChildData.Horizontal / mTpux, FixX)
        'If cWidth is negative, add it to FixX.
        cWidth = RightAnchor - cLeft
        If cWidth < 0 Then
            'Debug.Print "EnforceSashSub " & ChildIndex & " cWidth(<0)=" & cWidth
            cLeft = cLeft + cWidth
            FixX = FixX + cWidth
            cWidth = 0
        End If
    'Else Horizontal = ParentLeft - ChildLeft - ChildWidth
    ElseIf (ChildData.Sides And RE_LEFT) = RE_LEFT Then
        'ChildLeft = ParentLeft - ChildWidth - Horizontal
        cLeft = zSluffNeg2Fix(SashLeft - cWidth - ChildData.Horizontal / mTpux, FixX)
    ElseIf (ChildData.Sides And RE_WIDTH) = RE_WIDTH Then
        'ChildWidth = ParentLeft - ChildLeft - Horizontal
        cWidth = zSluffNeg2Fix(SashLeft - cLeft - ChildData.Horizontal / mTpux, FixX)
    End If  'It might be nither.

    cTop = ctlChild.Top
    cHeight = ctlChild.Height
    If (ChildData.Sides And RE_TOP + RE_HEIGHT) = RE_TOP + RE_HEIGHT Then
        BottomAnchor = cTop + cHeight
        'If cTop is negative, add it to FixY.
        cTop = zSluffNeg2Fix(SashTop - ChildData.Vertical / mTpuy, FixY)
        'If cHeight is negative, add it to FixY.
        cHeight = BottomAnchor - cTop
        If cHeight < 0 Then
            'Debug.Print "EnforceSashSub " & ChildIndex & " cHeight(<0)=" & cHeight
            cTop = cTop + cHeight
            FixY = FixY + cHeight
            cHeight = 0
        End If
    ElseIf (ChildData.Sides And RE_TOP) = RE_TOP Then
        cTop = zSluffNeg2Fix(SashTop - cHeight - ChildData.Vertical / mTpuy, FixY)
    ElseIf (ChildData.Sides And RE_HEIGHT) = RE_HEIGHT Then
        cHeight = zSluffNeg2Fix(SashTop - cTop - ChildData.Vertical / mTpuy, FixY)
    End If  'It might be nither.
        
    '****************************************************
    'Move child.
    '****************************************************
    If (ChildData.Sides And RE_HEIGHT) = RE_HEIGHT Then
        ctlChild.Move cLeft, cTop, cWidth, cHeight
    ElseIf (ChildData.Sides And RE_WIDTH) = RE_WIDTH Then
        ctlChild.Move cLeft, cTop, cWidth
    Else
        ctlChild.Move cLeft, cTop
    End If

    '****************************************************
    'The size might have snapped back a bit if squished too much.
    'If the right or bottom should be anchored
    'then we might have to move it again.
    '****************************************************
    If (ChildData.Sides And RE_LEFT + RE_WIDTH) = RE_LEFT + RE_WIDTH Then
        AnchorCorrection = RightAnchor - (ctlChild.Left + ctlChild.Width)
        If AnchorCorrection <> 0 Then
            'Debug.Print "EnforceSashSub " & ChildIndex & " Right AnchorCorrection(<>0)=" & AnchorCorrection
            IsMoveAgain = True
            cLeft = cLeft + AnchorCorrection
            FixX = FixX + AnchorCorrection
        End If
    ElseIf (ChildData.Sides And RE_WIDTH) = RE_WIDTH Then
        FixX = FixX + ctlChild.Width - cWidth
    End If
    If (ChildData.Sides And RE_TOP + RE_HEIGHT) = RE_TOP + RE_HEIGHT Then
        AnchorCorrection = BottomAnchor - (ctlChild.Top + ctlChild.Height)
        If AnchorCorrection <> 0 Then
            'Debug.Print "EnforceSashSub " & ChildIndex & " Bottom AnchorCorrection(<>0)=" & AnchorCorrection
            IsMoveAgain = True
            cTop = cTop + AnchorCorrection
            FixY = FixY + AnchorCorrection
        End If
    ElseIf (ChildData.Sides And RE_HEIGHT) = RE_HEIGHT Then
        FixY = FixY + ctlChild.Height - cHeight
    End If
    
    '****************************************************
    'Move child again.
    '****************************************************
    If IsMoveAgain Then
        ctlChild.Move cLeft, cTop
    End If
        
    '****************************************************
    'Is this correction bigger?
    '****************************************************
    'Debug.Print "EnforceSashSub " & ChildIndex & " FixY(<>0)=" & FixY & "; CorrectionY=" & CorrectionY
    If Abs(CorrectionX) < Abs(FixX) Then
        CorrectionX = FixX
    End If
    If Abs(CorrectionY) < Abs(FixY) Then
        CorrectionY = FixY
    End If
End Sub

Sub RemoveControl (ctl As Control)
    Dim i As Integer
    Dim j As Integer
    Dim k As Integer
    Dim DeleteCount As Integer

    '--------------------------------------------
    'Check the parent control array.
    For i = 0 To mControlCount - 1
        If mControl(i) Is ctl Then
            Set mControl(i) = Nothing
            DeleteCount = 0
            For j = 0 To mChildCount - 1
                If mChildData(j).ParentIndex = i Then
                    DeleteCount = DeleteCount + 1
                ElseIf DeleteCount > 0 Then
                    Set mChildControl(j - DeleteCount) = mChildControl(j)
                    mChildData(j - DeleteCount) = mChildData(j)
                End If
            Next 'j
            mChildCount = mChildCount - DeleteCount
        End If
    Next 'i


    '--------------------------------------------
    'Check the child control array.
    DeleteCount = 0
    For k = 0 To mChildCount - 1
        If mChildControl(k) Is ctl Then
            DeleteCount = DeleteCount + 1
        ElseIf DeleteCount > 0 Then
            Set mChildControl(k - DeleteCount) = mChildControl(k)
            mChildData(k - DeleteCount) = mChildData(k)
        End If
    Next 'k
    mChildCount = mChildCount - DeleteCount
End Sub

Sub RemoveForm (frm As Form)
    Const PROC = "RemoveForm"
    Dim i As Integer
    Dim DeleteCount As Integer

    '--------------------------------------------
    'Remove parent controls.
    For i = 0 To mControlCount - 1
        If mControl(i) Is Nothing Then
            'Skip it.
        ElseIf mControl(i).Parent Is frm Then
            Set mControl(i) = Nothing
        End If
    Next 'i

    '--------------------------------------------
    'Remove child controls.
    DeleteCount = 0
    For i = 0 To mChildCount - 1
        If mChildControl(i).Parent Is frm Then
            DeleteCount = DeleteCount + 1
        ElseIf DeleteCount > 0 Then
            Set mChildControl(i - DeleteCount) = mChildControl(i)
            mChildData(i - DeleteCount) = mChildData(i)
        End If
    Next 'i
    mChildCount = mChildCount - DeleteCount

    '--------------------------------------------
    'Remove forms last.
    For i = 0 To mFormCount - 1
        If mForm(i) Is frm Then
            Set mForm(i) = Nothing
        End If
    Next 'i
End Sub

Sub xBugItem (ByVal i As Integer)
    'd = mChildData(i)
    'Set c = mChildControl(i)
    'Debug.Print "Child " & i & " (Sides; Horiz; Vert; ParentType; ParentIndex)"
    'Debug.Print "Child Data: " & d.Sides & "; " & d.Horizontal & "; " & d.Vertical & "; " & d.ParentType & "; " & d.ParentIndex
    'Debug.Print "Child Caption: " & c '.Caption
    'If (d.Sides And RE_LEFT) = RE_LEFT Then
    '    Sides = Sides & "Left "
    'End If
    'If (d.Sides And RE_LEFT) = RE_LEFT Then
    '    Sides = Sides & "Left "
    'End If
    'If (d.Sides And RE_TOP) = RE_TOP Then
    '    Sides = Sides & "Top "
    'End If
    'If (d.Sides And RE_WIDTH) = RE_WIDTH Then
    '    Sides = Sides & "Width "
    'End If
    'If (d.Sides And RE_HEIGHT) = RE_HEIGHT Then
    '    Sides = Sides & "Height "
    'End If
    'Debug.Print "Child Sides: " & Sides
    'Debug.Print "Child: Left=" & c.Left & " Top=" & c.Top & " Width=" & c.Width & " Height=" & c.Height
    'i = d.ParentIndex
    'Select Case d.ParentType
    'Case PARENT_FORM
    '    Debug.Print "Parent Form Caption: " & mForm(i).Caption
    '    Debug.Print "Parent Form: Left=" & mForm(i).Left & " Top=" & mForm(i).Top & " Width=" & mForm(i).Width & " Height=" & mForm(i).Height
    'Case Else
    '    Set c = mControl(i)
    '    Select Case d.ParentType
    '    Case PARENT_CONTAINER
    '        Debug.Print "Parent Container Caption: " & mControl(i) '.Caption
    '    Case PARENT_SASH
    '        Debug.Print "Parent Sash Caption: " & mControl(i) '.Caption
    '    End Select
    '    Debug.Print "Parent: Left=" & c.Left & " Top=" & c.Top & " Width=" & c.Width & " Height=" & c.Height
    'End Select
End Sub

Private Sub xBugList ()
    'Dim i As Integer
    '
    'On Error Resume Next
    'If mChildCount = 0 Then
    '    Debug.Print "****** There are no lists. ******"
    '    Exit Sub
    'End If
    'Debug.Print "****** Lists ******"
    '
    'If mFormCount = 0 Then
    '    Debug.Print "*** There are no parent forms."
    'Else
    '    Debug.Print mFormCount & " PARENT FORMS"
    '    For i = 0 To mFormCount - 1
    '        Debug.Print "Parent Form " & i & ": " & mForm(i).Caption
    '    Next 'i
    'End If
    '
    'If mControlCount = 0 Then
    '    Debug.Print "*** There are no parent controls."
    'Else
    '    Debug.Print mControlCount & " PARENT CONTROLS"
    '    For i = 0 To mControlCount - 1
    '        Debug.Print "Parent Control " & i & ": " & mControl(i)
    '    Next 'i
    'End If
    '
    'Debug.Print mChildCount & " CHILD CONTROLS (Sides; Horiz; Vert; ParentType; ParentIndex)"
    'For i = 0 To mChildCount - 1
    '    Debug.Print "Child " & i & ": " & mChildControl(i) '.Caption
    '    Debug.Print "Child " & i & ": " & mChildData(i).Sides & "; " & mChildData(i).Horizontal & "; " & mChildData(i).Vertical & "; " & mChildData(i).ParentType & "; " & mChildData(i).ParentIndex
    'Next 'i
End Sub

Private Sub zAppendChild (ChildData As ReChildStruct, ctlChild As Control)
    If mChildCount = 0 Then
        ReDim mChildData(0 To 10)
        ReDim mChildControl(0 To 10)
    ElseIf mChildCount > UBound(mChildData) Then
        ReDim Preserve mChildData(0 To mChildCount + 10)
        ReDim Preserve mChildControl(0 To mChildCount + 10)
    End If
    mChildData(mChildCount) = ChildData
    Set mChildControl(mChildCount) = ctlChild
    mChildCount = mChildCount + 1
End Sub

Private Function zAppendParentControl (ctlParent As Control) As Integer
    If mControlCount = 0 Then
        ReDim mControl(0 To 10)
    ElseIf mControlCount > UBound(mControl) Then
        ReDim Preserve mControl(0 To mControlCount + 10)
    End If
    Set mControl(mControlCount) = ctlParent
    zAppendParentControl = mControlCount
    mControlCount = mControlCount + 1
End Function

Private Function zAppendParentForm (frmParent As Form) As Integer
    If mFormCount = 0 Then
        ReDim mForm(0 To 10)
    ElseIf mFormCount > UBound(mForm) Then
        ReDim Preserve mForm(0 To mFormCount + 10)
    End If
    Set mForm(mFormCount) = frmParent
    zAppendParentForm = mFormCount
    mFormCount = mFormCount + 1
End Function

Private Function zExternalScaleModeVB3 (ctlFrame As Control)
    'The Parent property is always a form.
    'If the control is in a container -- which would
    'be the true parent -- then the control's size
    'and position are in the ScaleMode of the
    'container (not the form).
    Dim hTrueParentWnd As Integer
    Dim ChildIndex As Integer
    Dim frmParent As Form
    Dim Count As Integer

    'Expect errors since master controls can and might be graphic.
    On Error GoTo zExternalScaleModeTrap
    hTrueParentWnd = ReGetParentAPI(ctlFrame.hWnd)
    On Error GoTo 0
    Set frmParent = ctlFrame.Parent
    If hTrueParentWnd = frmParent.hWnd Then
        'The control is drawn right on the form.
        zExternalScaleModeVB3 = frmParent.ScaleMode
    Else
        'We'll have to search for the true parent.
        Count = frmParent.Controls.Count
        For ChildIndex = 0 To Count - 1
            'Not all controls have handles.
            If zhControlWnd(frmParent.Controls(ChildIndex)) = hTrueParentWnd Then
                Exit For
            End If
        Next ChildIndex
        'We better have found it.
        If ChildIndex >= Count Then
            'This is bad. Just use the form's ScaleMode.
            zExternalScaleModeVB3 = ctlFrame.Parent.ScaleMode
        Else
            'Get the true parent/container's ScaleMode
            'Not all container controls have ScaleModes.
            zExternalScaleModeVB3 = zInternalScaleMode(frmParent.Controls(ChildIndex))
        End If
    End If
    Exit Function

zExternalScaleModeTrap:
    'This control is graphic, does not have a hWnd property,
    'and therefore GetParent cannot be used.
    zExternalScaleModeVB3 = ctlFrame.Parent.ScaleMode
    Exit Function
End Function

Private Function zExternalScaleModeVB4 (ctlFrame As Control)
    'VB4 has the Container property.
    'So, this code gets simpler and better.
    '-------------------------------------
    'The Parent property is always a form.
    'If the control is in a container -- which would
    'be the true parent -- then the control's size
    'and position are in the ScaleMode of the
    'container (not the form).
    
'    If ctlFrame.Container Is ctlFrame.Parent Then
'        'The control is drawn right on the form.
'        zExternalScaleModeVB4 = ctlFrame.Parent.ScaleMode
'    Else
'        zExternalScaleModeVB4 = zInternalScaleMode(ctlFrame.Container)
'    End If
End Function

Private Function zhControlWnd (ctl As Control) As Integer
    'Lightweight/graphic controls don't have Windows handles.
    'So, an error is expected.
    'Return 0 for graphic controls.
    On Error GoTo zhControlWndTrap
    zhControlWnd = ctl.hWnd
zhControlWndTrap:
    Exit Function
End Function

Private Function zInternalScaleMode (frame As Control) As Integer
    'Some container controls do not have
    'a ScaleMode property.
    'So, an error is expected.
    'In this case the default is TWIPS.

    On Error GoTo zControlScaleModeTrap
    zInternalScaleMode = frame.ScaleMode
    Exit Function

zControlScaleModeTrap:
    zInternalScaleMode = TWIPS
    Exit Function
End Function

Private Function zMakeParentControlIndex (ctlParent As Control)
    'See if the frame is already stored.
    'If it's not, then store it.
    Dim i As Integer
    Dim EmptySlotIndex As Integer

    'While we're at it, find an empty slot.
    EmptySlotIndex = -1
    For i = 0 To mControlCount - 1
        If mControl(i) Is Nothing Then
            'We found an empty slot.
            'Some frame control must have been unloaded.
            EmptySlotIndex = i
        ElseIf mControl(i) Is ctlParent Then
            'The control is already in the list.
            zMakeParentControlIndex = i
            Exit Function
        End If
    Next 'i

    'Never found it
    If EmptySlotIndex < 0 Then
        'No empty spots available.
        zMakeParentControlIndex = zAppendParentControl(ctlParent)
    Else 'Use the empty slot.
        Set mControl(EmptySlotIndex) = ctlParent
        zMakeParentControlIndex = EmptySlotIndex
    End If
End Function

Private Function zMakeParentFormIndex (frmParent As Form)
    'See if the form is already stored.
    'If it's not, then store it.
    Dim i As Integer
    Dim EmptySlotIndex As Integer

    'While we're at it, try to find an empty slot.
    EmptySlotIndex = -1
    For i = 0 To mFormCount - 1
        If mForm(i) Is Nothing Then
            'We found an empty slot.
            'Some form must have been unloaded.
            EmptySlotIndex = i
        ElseIf mForm(i) Is frmParent Then
            'The form is already in the list.
            zMakeParentFormIndex = i
            Exit Function
        End If
    Next 'i

    'Never found it.
    If EmptySlotIndex < 0 Then
        'No empty spots available.
        zMakeParentFormIndex = zAppendParentForm(frmParent)
    Else 'Use the empty slot.
        Set mForm(EmptySlotIndex) = frmParent
        zMakeParentFormIndex = EmptySlotIndex
    End If
End Function

Private Function zSluffNeg2Fix (ByVal Amount As Long, rFix As Long) As Long
    If Amount < 0 Then
         rFix = rFix - Amount
    Else : zSluffNeg2Fix = Amount
    End If
End Function

Private Function zValidateScaleMode (ByVal ScaleMode As Integer)
    'The ScaleMode must be TWIPS or PIXELS.
    'Don't hang around or generate an error if it isn't.
    'The external scale mode of a form is always TWIPS.
    'Ex:   If zValidateScaleMode(TWIPS) then ...
    'Forms always have the ScaleMode property.
    'All mesurements are kept in Twips.
    '   Twips = Pixels * mTpu
    '   Pixels = Twips / mTpu
    zValidateScaleMode = True
    Select Case ScaleMode
    Case PIXELS
        mTpux = Screen.TwipsPerPixelX
        mTpuy = Screen.TwipsPerPixelY
    Case TWIPS
        mTpux = 1
        mTpuy = 1
    Case Else
        RepositionMessage = "Form and control ScaleMode must be Twip or Pixel."
        zValidateScaleMode = False
    End Select
End Function