Lines do not print in some circumstances.

This is very curious. A long standing problem that has me stumped. When drawing simple lines, they show up perfectly on-screen in Adobe Reader 9. But when the PDF is printed to paper, the lines are not there. However, if I go into Advanced tab on Printer Settings and change Printer Features / Graphics Mode: Send Graphics as Vector to instead be Send Graphics as Raster, they print just fine. This is printing to an HP Color LaserJet 4700 under Windows 7, 64-bit.

I can not determine if the issue is in 1) how I am calling PDFNet V 2) Adobe Reader or 3) the HP print driver.

My VB.NET routine for drawing horizontal lines is part of a larger render library, and is as follows. All passed parameters are in inches, so some values are converted with the HItoPT and VItoPT routines. Some small displacements of a half line are made to help make the corners match up better when this is combined with vertical line drawing.

     Public Overrides Sub HLine( _
             ByVal HorizontalPosition1 As Single, _
             ByVal HorizontalPosition2 As Single, _
             ByVal VerticalPosition As Single, _
             ByVal Thickness As Single)


         Dim elm As Element
         Dim gstate As GState


         mOut.mEB.MoveTo(HItoPt(HorizontalPosition1 - (Thickness / 2)), VItoPt(VerticalPosition))
         mOut.mEB.LineTo(HItoPt(HorizontalPosition2 + (Thickness / 2)), VItoPt(VerticalPosition))
         elm = mOut.mEB.PathEnd

         gstate = elm.GetGState
         If Color = Drawing.Color.Black Then
             gstate.SetStrokeColor(New ColorPt(0, 0, 0))
             gstate.SetStrokeColor(New ColorPt(Color.R / 255.0, Color.G / 255.0, Color.B / 255.0))
         End If
         gstate.SetLineWidth(Thickness * 72.0)


         CurrentHorizontalPosition = HorizontalPosition1
         CurrentVerticalPosition = VerticalPosition

     End Sub

I really hope there is an issue with the way I am calling PDFNet. Thanks for your help.
Lee Gillie, CCP
Online Data Processing, Inc.

I believe that the issue is related to driver or Acrobat. You may be able to work arond this by increasing the line thickness.
What are the results if you print the file with PDFNet?