Why might an Advanced Zone Locator report an "Invalid argument specified" or "Out of Memory" error when adequate system resources are still available?

Question / Problem:

Why might an Advanced Zone Locator report an "Invalid argument specified" or "Out of Memory" error when adequate system resources are still available?

Answer / Solution:

An Advanced Zone Locator might return an error like the following when it tries to extract information from a zone that extends beyond the bounds of the page:

BeforeExtraction: BeforeExtract: The execution of a locator method failed. Class = "Cover", 
Locator = "AZL_Requestor", Original error message: Out of memory

This can also be a problem if the zones of the AZL are being relocated in a script and care is not taken to ensure that they are not moved off of the page.

In KTM 5.5, off-page zones are handled without error, but in previous versions, a script can be used to prevent the error by invalidating zones which go off of the page.

The following script function should be called from a Script Locator positioned before the AZL and after any script which is relocating AZL zones:

'Prevent AZL Zones which might go off a page from causing an error
'Call this after any script that moves AZL zones and before the actual AZL
'This can also cause the AZL to have alternatives with zeroed coordinates on PageNr - 1
'The only implication is that script using these values directly
'should check if the page number is valid
Public Sub FixAZLCoordinates(ByVal pXdoc As CscXDocument)
    Dim Rep As CscXDocRepresentation
    Set Rep = pXdoc.Representations(0)

    Dim iZone As Integer
    Dim oZone As CscXDocZone
    Dim iPage As Integer
    Dim NewZones()
    ReDim NewZones(0)
    'go through zones (backwards so removing items is fine)
    For iZone = Rep.Zones.Count - 1 To 0 Step -1
        Set oZone = Rep.Zones(iZone)
        'go through pages
        For iPage = 0 To pXdoc.Pages.Count - 1
            Dim ZoneIsOnThisPage As Boolean
            If oZone.PageNr = iPage Then
                ZoneIsOnThisPage = True
            Else
                ZoneIsOnThisPage = False
            End If
            If ZoneIsOnThisPage Then
                Dim ZoneOffPageTooFarRight As Boolean
                ZoneOffPageTooFarRight = (oZone.Left + oZone.Width) > pXdoc.Pages.ItemByIndex(iPage).Width
                Dim ZoneOffPageTooLow As Boolean
                ZoneOffPageTooLow = (oZone.Top + oZone.Height) > pXdoc.Pages.ItemByIndex(iPage).Height
                If ZoneOffPageTooFarRight Or ZoneOffPageTooLow Then
                    'Remove the zone (will not cause index problems because
                    'we are stepping through backwards)
                    'Trace "Removing Zone: " & oZone.Name & ", TooRight/TooLow: " & _
                    'ZoneOffPageTooFarRight & "/" & ZoneOffPageTooLow
                    Rep.Zones.Remove(iZone)

                    'Create new zone
                    Dim oZoneNew As CscXDocZone
                    Set oZoneNew = New CscXDocZone
                    oZoneNew.Name = oZone.Name
                    oZoneNew.PageNr = oZone.PageNr
                    oZoneNew.Left = 0
                    oZoneNew.Width = 0
                    oZoneNew.Top = 0
                    oZoneNew.Height = 0
                    
                    'Add zone to array (we don't want to append it while we are
                    ' still iterating though the zones)
                    ReDim Preserve NewZones(UBound(NewZones) + 1)
                    Set NewZones(UBound(NewZones)) = oZoneNew
                End If
            End If
        Next
    Next
    Dim i As Integer
    Dim ZoneToAppend As CscXDocZone
    For i = 0 To UBound(NewZones)
        If Not IsEmpty(NewZones(i)) Then
            Set ZoneToAppend=NewZones(i)
            'Trace "Appending new zone: " & ZoneToAppend.Name
            Rep.Zones.Append ZoneToAppend
        End If
    Next
End Sub

Applies to: