Converting Dialog Units into Pixels

[Ideas Man]

I've been trying to convert the measurements for Wizards from the Wizard97 specification into pixels for god knows how long now and I can't ever seem to get it to look right at all.

If you see this page on Welcome and Completion Page Layouts, all the measurements are in Dialog Units for some special reason I can't recall at this point in time.

Anyway, after spending a while looking for the stuff todo it, I found the GetDialogBaseUnits() function, made a little wrapper for it and when I try to align the controls on my form to the measurements provided by the specification, they are nowhere near them.

Here's my attempt at wrapping the API up:

Public Class DialogUnits
 
    Private Declare Function GetDialogBaseUnits Lib "user32" () As Integer
 
    Private _Width As Integer
    Private _Height As Integer
 
    Public Sub New()
        Call CalculateDialogUnits()
    End Sub
 
    Public ReadOnly Property Width() As Integer
        Get
            Return _Width
        End Get
    End Property
 
    Public ReadOnly Property Height() As Integer
        Get
            Return _Height
        End Get
    End Property
 
    Public Function GetHeightInPixels(ByVal dialogUnits As Integer) As Integer
        Return (_Height * dialogUnits) / 8
    End Function
 
    Public Function GetWidthInPixels(ByVal dialogUnits As Integer) As Integer
        Return (_Width * dialogUnits) / 4
    End Function
 
    Public ReadOnly Property Size() As SizeF
        Get
            Return New SizeF(_Width, _Height)
        End Get
    End Property
 
    Private Sub CalculateDialogUnits()
        Dim DialogUnits As Long = GetDialogBaseUnits
 
        _Width = LongManipulation.GetLoWord(DialogUnits)
        _Height = LongManipulation.GetHiWord(DialogUnits)
    End Sub
 
End Class

And the LongManipulation class:

Public Class LongManipulation
 
    Public Shared Function GetLoWord(ByVal sourceLong As Long) As Integer
        Return (sourceLong / &H10000) And &HFFFF&
    End Function
 
    Public Shared Function GetHiWord(ByVal sourceLong As Long) As Integer
        Return sourceLong And &HFFFF&
    End Function
 
    Public Shared Function IntegersToLong(ByVal loWord As Integer, ByVal hiWord As Integer) As Long
        Return (hiWord * &H10000) + (loWord And &HFFFF&)
    End Function
 
End Class

Can someone please show me where I'm going wrong because I got no idea what I'm doing wrong. It seems to be logically correct, but something's a miss.

[wossname]

http://support.microsoft.com/default...b;en-us;125681

??

[wossname]

Public Class LongManipulation
 
    Public Shared Function GetLoWord(ByVal sourceLong As Long) As Integer
        Return CType(sourceLong And &HFFFF&, Integer)
    End Function
 
    Public Shared Function GetHiWord(ByVal sourceLong As Long) As Integer
        Return CType((sourceLong >> 16) And &HFFFF&, Integer)
    End Function
 
    Public Shared Function IntegersToLong(ByVal loWord As Integer, ByVal hiWord As Integer) As Long
        Return (hiWord << 16) Or loWord
    End Function
 
End Class

[Ideas Man]

... that doesn't exactly help me . I'm not worried about the IntegersToLong function, that was just something that was tagged on when I found that code, and the KB article didn't help all too much sorry.

[wossname]

I revised my code again, try it now.

[Ideas Man]

No, doesn't seem to.

Have a go, put a label on the form and use my functions to try and place it as they have it on the form.

[wossname]

I'm not worried about the IntegersToLong function

Perhaps you should be.

You just don't do binary operations with division and multiplication operators. Especially when extracting words.

Use bitshift operators (<<, >>) instead.

If you use divide instead of >> then you will get incorrect results because the low byte is included in the operation, >> 16 ignores the low byte.

That whole LongManipulation class looked a bit suspect if you ask me.

[Ideas Man]

Perhaps you should be.

You just don't do binary operations with division and multiplication operators. Especially when extracting words.

Use bitshift operators (<<, >>) instead.

If you use divide instead of >> then you will get incorrect results because the low byte is included in the operation, >> 16 ignores the low byte.

That whole LongManipulation class looked a bit suspect if you ask me.

Well, I didn't supply the code for it, so I don't know how it works, it just "seemed" to work.