In a dual-monitor system, finding out on which monitor a PowerPoint slideshow is displayed

Question

In Powerpoint 2007/2010 run on a multiple monitor system, we can select the monitor on which the slideshow will be shown by going to "Slide Show"-> "Set up slideShow" -> "Display SlideShow on" and selecting the desired monitor.

Is it possible to programmatically determine these settings (e.g. using VBA)?

What I actually need is the pixel-resolution of the monitor on which the slideshow is shown. How can I do that?

Answer 1

Try this:

With SlideShowWindows(1)
Debug.Print .Height
Debug.Print .Width
End With

That'll give you results in points. There are 72 points to the inch, so:

ResultInPixels = (ResultInPoints * WindowsDPI) / 72

Typically WindowsDPI is 96 but you can't rely on that. API calls to GetSystemMetrics will give you the current value.

Answer 2

Even if you already accepted Steve's answer. Here are a few useful snippets of code.

You can get info about system monitor with this kind of code (found here):

Attribute VB_Name = "MonitorInfo"
Option Explicit

Public Declare Function LoadLibraryEx Lib "kernel32.dll" Alias "LoadLibraryExA" (ByVal lpFileName As String, ByVal hFile As Long, ByVal dwFlags As Long) As Long
Public Declare Function GetProcAddress Lib "kernel32.dll" (ByVal hModule As Long, ByVal lpProcName As String) As Long
Public Declare Function GetModuleHandle Lib "kernel32.dll" Alias "GetModuleHandleA" (ByVal lpModuleName As String) As Long
Public Declare Function FreeLibrary Lib "kernel32.dll" (ByVal hLibModule As Long) As Boolean
Public Declare Function EnumDisplayMonitors Lib "user32.dll" (ByVal hdc As Long, ByRef lprcClip As Any, ByVal lpfnEnum As Long, ByVal dwData As Long) As Boolean
Public Declare Function GetMonitorInfo Lib "user32.dll" Alias "GetMonitorInfoA" (ByVal hMonitor As Long, ByRef lpmi As MONITORINFOEX) As Boolean

Public Const CCHDEVICENAME = 32
Public Const MONITORINFOF_PRIMARY = &H1

Public Type RECT
    Left As Long
    Top As Long
    Right As Long
    Bottom As Long
End Type

Public Type MONITORINFOEX
    cbSize As Long
    rcMonitor As RECT
    rcWork As RECT
    dwFlags As Long
    szDevice As String * CCHDEVICENAME
End Type

Dim MonitorId() As String

Public Sub Test()
Dim i As Integer
    Debug.Print "Number of monitors in this system : " & GetMonitorId
    Debug.Print
    For i = 1 To UBound(MonitorId)
        PrintMonitorInfo (MonitorId(i))
    Next i
End Sub

Public Function GetMonitorId()
    ReDim MonitorId(0)
    ' Of course dual screen systems are not available on all Win versions.
    If FunctionExist("user32.dll", "EnumDisplayMonitors") = True Then
        If EnumDisplayMonitors(&H0, ByVal &H0, AddressOf MonitorEnumProc, &H0) = False Then
            Failed "EnumDisplayMonitors"
        End If
    End If
    GetMonitorId = UBound(MonitorId)
End Function


Private Sub PrintMonitorInfo(ForMonitorID As String)
Dim MONITORINFOEX As MONITORINFOEX
    MONITORINFOEX.cbSize = Len(MONITORINFOEX)
    If GetMonitorInfo(CLng(ForMonitorID), MONITORINFOEX) = False Then Failed "GetMonitorInfo"
    With MONITORINFOEX
        Debug.Print "Monitor info for device number : " & ForMonitorID
        Debug.Print "---------------------------------------------------"
        Debug.Print "Device Name : " & .szDevice
        If .dwFlags And MONITORINFOF_PRIMARY Then Debug.Print "Primary Display = True" Else Debug.Print "Primary Display = False"
        With .rcMonitor
            Debug.Print "Monitor Left : " & .Left
            Debug.Print "Monitor Top : " & .Top
            Debug.Print "Monitor Right : " & .Right
            Debug.Print "Monitor Bottom : " & .Bottom
        End With
        With .rcWork
            Debug.Print "Work area Left : " & .Left
            Debug.Print "Work area Top : " & .Top
            Debug.Print "Work area Right : " & .Right
            Debug.Print "Work area Bottom : " & .Bottom
        End With
    End With
    Debug.Print
    Debug.Print
End Sub


Public Function FunctionExist(ByVal strModule As String, ByVal strFunction As String) As Boolean
Dim hHandle As Long
    hHandle = GetModuleHandle(strModule)
    If hHandle = &H0 Then
        Failed "GetModuleHandle"
        hHandle = LoadLibraryEx(strModule, &H0, &H0): If hHandle = &H0 Then Failed "LoadLibrary"
        If GetProcAddress(hHandle, strFunction) = &H0 Then
            Failed "GetProcAddress"
        Else
            FunctionExist = True
        End If
        If FreeLibrary(hHandle) = False Then Failed "FreeLibrary"
    Else
        If GetProcAddress(hHandle, strFunction) = &H0 Then
            Failed "GetProcAddress"
        Else
            FunctionExist = True
        End If
    End If
End Function


Public Sub Failed(ByVal strFunction As String)
    If errMsg = True Then
        If Err.LastDllError = 0 Then
            MessageBoxEx &H0, strFunction & Chr$(13) & Chr$(10) & Chr$(13) & Chr$(10) & "Failed", "Error", MB_OK Or MB_ICONWARNING Or MB_SETFOREGROUND, 0
        Else
            Errors Err.LastDllError, strFunction
        End If
    End If
End Sub


Public Function MonitorEnumProc(ByVal hMonitor As Long, ByVal hdcMonitor As Long, ByRef lprcMonitor As RECT, ByVal dwData As Long) As Boolean
Dim ub As Integer
    ub = 0
    On Error Resume Next
    ub = UBound(MonitorId)
    On Error GoTo 0
    ReDim Preserve MonitorId(ub + 1)
    MonitorId(UBound(MonitorId)) = CStr(hMonitor)
    MonitorEnumProc = 1
End Function

And compare the results with the current SlideShowWindows(1) results.

Answer 3

The code @JMax from Edwin Vermeer is really great. I'm sure I'll get smashed by the mods for this but I made the below diagram to show exactly what Sub test() in the code returns. Hopefully this will save another n00b an hour or two.

Tip: Find-replace Dubug.Print with MsgBox and run through the code a few times with different monitor arrangements to make sure you understand the returns.

The below is an odd monitor arrangement bet it demonstrates well the different returns you'll get:

...well it won't let me post pics until I have 10 reputation, diagrams are here:

"Monitor" returns for Primary monitor

"Work area" returns for Primary monitor

"Monitor/Work area" returns for Secondary monitor

(in the same album as the other 2, need 10 reputation to post >2 links...)