Calculate text height based on available width and font?

Question

We are creating PDF documents on the fly from the database using PDFsharp.

I need to know the best way to calculate the height of the text area based on the font use

Answer 1

The OP asked how to calculate text height based on available width and font. Windows .NET provides an API call for this which takes a width argument; the version of PDFsharp I'm using (0.9.653, .NET 1.1) does not.

My solution - use the .NET API call with a Graphics object allocated for a custom-created Bitmap object to get the answer.

What worked for me was to use a Bitmap that had 100 DPI resolution (critical) and happened to be the size of a Portrait page (probably less critical).

Then I just asked .NET what the pixel size would be for painting on that bitmap.

You probably will then want to convert the units from 1/100th of an inch to Points (for PDFsharp).

''' Adapted Code - this not tested or even compiled - Caveat Emptor!
''' Target: Visual Basic, .NET 1.1 (VS2003) [adapt as necessary]

'  '  '  '  '  '  '  '  '  '  '  '  '  '  '  '
'  GraphicsAlt.MeasureString() does substantially what System.Drawing MeasureString(...,Integer) does.
'  '  '  '  '  '  '  '  '  '  '  '  '  '  '  '
Public Module GraphicsAlt

    '
    ' Static data used Only to compute MeasureString() below.
    '
    '     Cache a single copy of these two objects, to address an otherwise unexplained intermittent exception.
    '
    Private Shared myImage As Bitmap = Nothing
    Private Shared myGraphics As Graphics = Nothing

    Public Shared Function GetMeasureGraphics() As Graphics
        If myImage Is Nothing Then
            myImage = New Bitmap(1700, 2200)  '' ... Specify 8.5x11 
            myImage.SetResolution(100, 100)   '' ... and 100 DPI (if you want different units, you might change this)
            myGraphics = Graphics.FromImage(myImage)
        End If
        Return myGraphics
    End Function

    'Given 1/100TH inch max width, return Rect to hold with units 1/100TH inch
    '
    Public Function MeasureString(ByVal text As String, ByVal aFont As System.Drawing.Font, ByVal width As Integer) As System.Drawing.SizeF
        Return (GraphicsAlt.GetMeasureGraphics()).MeasureString(text, aFont, width)
    End Function

End Module