PowerPoint -> PDF (Part 2)

After writing a VBA Macro to convert a PowerPoint with animation into a flat PowerPoint without animation (suitable for conversion to PDF), I wrote my talk. After writing my talk I realised I not only needed elements to appear on a click, but also disappear and reappear. Unfortunately my original macro script did not do that, so I've updated it with two new features:

Safer

The original code removed all slides which were not hidden to return to the previous state. Unfortunately, if you haven't yet run the AddElements script, that results in it deleting all your slides! Undo saves the day, but it would be nicer for RemElements to be a bit more considerate. This version tags all the slides it creates, then RemElements simply removes those with the appropriate tag - hopefully this removes the obvious "Doh!" moment from this tool.

Works with show/hide/reshow

The original code used the Shape.AnimationSettings properties to detect what happened to objects. Unfortunately, this property only records the first action associated with an object - I suspect in the past PowerPoint only allowed one action and this is merely here for compatibility. To get the full range of events you need to use the Slide.TimeLine property. Writing the code I ran into two issues: (1) objects with silly names; (2) mutability.

Objects With Silly Names

Some objects have properties which don't do what you might think! Effect.EffectType = msoAnimEffectAppear implies that the animation is to appear, but if Effect.Exit = msoTrue then this is the disappear effect! I was confused by this one for quite a while.

In order to solve all the naming problems, I made extensive use of the Visual Basic debugger included with Office, which puts many other debuggers to shame. It is at least 1000x better than any Haskell debugger I've ever seen, and equally far ahead of things like GDB. Microsoft's software may be maligned, but their debuggers are truly fantastic! It really does allow an entirely new style of development, and is particularly suited to dipping into a new API without having a large learning curve.

Mutability

Mutability is a bad idea. If you delete a shape, while you are iterating over a collection of shapes, you silently skip the element that comes after the deleted shape! If you delete a shape, and that shape is the subject of a transition, then that corresponding transition is deleted. If you change the Shape.AnimationSettings.Animate to msoFalse, this removes any associated transitions. All this means that to try and iterate over something starts to become a challenge!

The problem with mutability in this particular task is that it is unclear what is changing and when, leading to subtle bugs and lots of debugging. Again, the debugger helped, but not as much as before - having to single-step through quite deep properties is not a particularly fun task.

The Code

And here is the code, to be use as in the same way to the previous post.

Option Explicit

Sub AddElements()
Dim shp As Shape

Dim i As Integer, n As Integer
n = ActivePresentation.Slides.Count
For i = 1 To n
    Dim s As Slide
    Set s = ActivePresentation.Slides(i)
    s.SlideShowTransition.Hidden = msoTrue
    
    Dim max As Integer: max = AnimationElements(s)
    Dim k As Integer, s2 As Slide
    For k = 1 To max
        Set s2 = s.Duplicate(1)
        s2.Name = "AutoGenerated: " & s2.SlideID
        s2.SlideShowTransition.Hidden = msoFalse
        s2.MoveTo ActivePresentation.Slides.Count
        
        Dim i2 As Integer, h As Shape
        Dim Del As New Collection
        For i2 = s2.Shapes.Count To 1 Step -1
            Set h = s2.Shapes(i2)
            If Not IsVisible(s2, h, k) Then Del.Add h
        Next
        Dim j As Integer
        For j = s.TimeLine.MainSequence.Count To 1 Step -1
            s2.TimeLine.MainSequence.Item(1).Delete
        Next
        For j = Del.Count To 1 Step -1
            Del(j).Delete
            Del.Remove j
        Next
    Next
Next
End Sub

'is the shape on this slide visible at point this time step (1..n)
Function IsVisible(s As Slide, h As Shape, i As Integer) As Boolean

'first search for a start state
Dim e As Effect
IsVisible = True
For Each e In s.TimeLine.MainSequence
    If e.Shape Is h Then
        IsVisible = Not (e.Exit = msoFalse)
        Exit For
    End If
Next

'now run forward animating it
Dim n As Integer: n = 1
For Each e In s.TimeLine.MainSequence
    If e.Timing.TriggerType = msoAnimTriggerOnPageClick Then n = n + 1
    If n > i Then Exit For
    If e.Shape Is h Then IsVisible = (e.Exit = msoFalse)
Next
End Function

'How many animation steps are there
'1 for a slide with no additional elements
Function AnimationElements(s As Slide) As Integer
AnimationElements = 1
Dim e As Effect
For Each e In s.TimeLine.MainSequence
    If e.Timing.TriggerType = msoAnimTriggerOnPageClick Then
        AnimationElements = AnimationElements + 1
    End If
Next
End Function

Sub RemElements()
Dim i As Integer, n As Integer
Dim s As Slide
n = ActivePresentation.Slides.Count
For i = n To 1 Step -1
    Set s = ActivePresentation.Slides(i)
    If s.SlideShowTransition.Hidden = msoTrue Then
        s.SlideShowTransition.Hidden = msoFalse
    ElseIf Left$(s.Name, 13) = "AutoGenerated" Then
        s.Delete
    End If
Next
End Sub

As before, no warranty, and please do backup first!