DocumentEmfPage Class

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Forms.DocumentWriters
Imports Leadtools.Forms.Ocr

      
Public Sub DocumentEmfPageExample()
   ' Output PDF file name
   Dim pdfFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Example.pdf")
   ' Document properties, each page is 8.5 by 11 inches at 300 DPI. Typical dimensions
   Dim resolution As Integer = 300
   Dim pageWidth As Integer = CInt(8.5 * resolution)
   Dim pageHeight As Integer = CInt(11 * resolution)

   ' Create the document writer
   Dim docWriter As New DocumentWriter()
   docWriter.BeginDocument(pdfFileName, DocumentFormat.Pdf)

   For pageNumber As Integer = 1 To 2
      Dim page As New DocumentEmfPage()
      page.EmfHandle = GetPageEmf(pageNumber, pageWidth, pageHeight, resolution)
      docWriter.AddPage(page)

      If page.EmfHandle <> IntPtr.Zero Then
         DeleteEnhMetaFile(page.EmfHandle)
      End If
   Next

   docWriter.EndDocument()

   ' Show the PDF file
   System.Diagnostics.Process.Start(pdfFileName)
End Sub

Private Shared Function GetPageEmf(pageNumber As Integer, pageWidth As Integer, pageHeight As Integer, resolution As Integer) As IntPtr
   ' Get the screen DC
   Using graphicsScreen As Graphics = Graphics.FromHwndInternal(IntPtr.Zero)
      Dim hdcScreen As IntPtr = graphicsScreen.GetHdc()

      ' Calculate the EMF rectangle in 1/100 mm
      Dim frameRect As New RectangleF( _
         0, _
         0, _
         CType((pageWidth * 2540.0F + resolution / 2.0) / resolution, Single), _
         CType((pageHeight * 2540.0F + resolution / 2.0) / resolution, Single))

      ' Create the EMF, GDI compatible
      Using metaFile As New Metafile(hdcScreen, frameRect, MetafileFrameUnit.GdiCompatible, EmfType.EmfOnly, Nothing)
         ' No need for this anymore
         graphicsScreen.ReleaseHdc(hdcScreen)

         ' Now create the graphics to draw in from the metafile
         Using graphics As Graphics = graphics.FromImage(metaFile)
            ' Get the EMF DPI
            Dim header As MetafileHeader = metaFile.GetMetafileHeader()
            Dim emfDpiX As Single = header.DpiX
            Dim emfDpiY As Single = header.DpiY

            ' We must convert each value we want from pixels to EMF coordinates, so use a scale
            graphics.ScaleTransform(emfDpiX / resolution, emfDpiY / resolution)

            ' To draw font, we must use this scale value to convert from point size
            Dim fontScale As Single = CType(resolution, Single) / Math.Max(graphics.DpiX, graphics.DpiY)

            ' Ready, now we can draw...

            ' Fill it with white
            Dim rc As New RectangleF(0, 0, pageWidth, pageHeight)
            graphics.FillRectangle(Brushes.White, rc)

            ' Put a frame
            rc = New RectangleF(1, 1, pageWidth - 2, pageHeight - 2)
            graphics.DrawRectangle(Pens.DarkGreen, rc.X, rc.Y, rc.Width, rc.Height)

            ' Draw some text
            Dim text As String = "This is page " + pageNumber.ToString()

            Dim pointSize As Single = 20 * fontScale
            ' fonts need to converted to scaled back, so ...
            Using font As New Font("Arial", pointSize, FontStyle.Regular)
               graphics.DrawString(text, font, Brushes.Black, 0, 0)
            End Using

            ' Add some vector objects, red line
            rc = New Rectangle(50, 50, pageWidth - 100, pageHeight - 100)
            graphics.DrawLine(Pens.Red, rc.Left, rc.Top, rc.Right, rc.Bottom)

            ' blue rect somewhere
            rc = New Rectangle(100, 100, 150, 100)
            graphics.FillRectangle(Brushes.Blue, rc)
         End Using

         Return metaFile.GetHenhmetafile()
      End Using
   End Using
End Function

' GDI interop
<DllImport("gdi32.dll")> _
Private Shared Function DeleteEnhMetaFile(hemf As IntPtr) As Integer
End Function