Why might an Advanced Zone Locator throw an Out of Memory error when the system is not actually out of memory?

Question / Problem:

Why might an Advanced Zone Locator throw an Out of Memory error when the system is not actually out of memory?

Answer / Solution:

This can occur if an Advanced Zone Locator (AZL) zone is off of the page from which it is trying to extract data. Usually the only reason that a zone would be off of the page is if the pages being processed are a different size or DPI than the reference image that was used to configure the locator, or, if the AZL zones were relocated in script and they are placed off of the page.

KTM 5.5 has been improved to handle these zones with invalid locations. In previous versions, if these situations cannot be avoided, the following function can be called from a script locator which runs before the AZL. It will move any zones with invalid locations and prevent the error.

'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
'It seems that this can cause the AZL to have alternatives with zeroed coordinates on PageNr -1
'The only implication is that script which uses these alternatives should
'check for valid values
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 with zeroed coordinates which will always be on the page
                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 itterating though the zones)
                ReDim Preserve NewZones(UBound(NewZones)+1)
                Set NewZones(UBound(NewZones)) = oZoneNew
            End If
        End If
        Next
    Next
    'Add the new zones
    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: