Why is PdfSharp creating borders around web links?

Question

I have the following function to create a weblink using PdfSharp:

    public static void AddWebLink(XGraphics gfx, PdfPage page, XFont font, string url, string text, int startX, int startY)
    {
        if (gfx == null)
            throw new ArgumentNullException("gfx");

        if (page == null)
            throw new ArgumentNullException("page");

        if (font == null)
            throw new ArgumentNullException("font");

        // Write out the text
        gfx.DrawString(text, font, XBrushes.Blue, new PointF(startX, startY));
        var stringSize = gfx.MeasureString(text, font);

        // Create the linked area
        // For some reason the Y of the rectangle needs to be startY minus the height
        startY -= (int)stringSize.Height;

        var rect = gfx.Transformer.WorldToDefaultPage(new XRect(startX, startY, stringSize.Width, stringSize.Height));
        var pdfRect = new PdfRectangle(rect);
        var annotation = page.AddWebLink(pdfRect, url);
        annotation.Opacity = 0; // Try and prevent it from rendering a box around the link in some viewers
    }

When the PDF is generated, everything is fine when viewed in Foxit Reader:

However, Adobe Acrobat Reader 10 and 11 shows a black-thin border around the linked area:

Acrobat http://dl.dropbox.com/u/6753359/acrobat-bad.PNG

Unfortunately, since Acrobat Reader is more standard it's a requirement that it must look right in it.

Can someone clue me in as to why all of my link areas are getting borders in them in acrobat reader?

---

Edit: I tried to make the annotation invisible by both annotation.Opacity = 0 and annotation.Color = XColor.FromArgb(255, 255, 255, 255);. The former did not work (border still appeared), the latter made the border white which doesn't 100% work because it creates oddities in some lines of text (like a white line cutting off the bottom of y's, p's, etc...).

Answer 1

It's a known problem.

The solution can be found here: http://forum.pdfsharp.net/viewtopic.php?p=6161#p6161

The frame is a bug in PDFsharp. It's a bug in Adobe Reader up to 10.0.3 not to display the frame.

Update: The bug was fixed a long time ago and links created with recent versions will not have frames around them.

Answer 2

I resolved this issue by:

1.) Downloading the latest release of PDFSharp from CodePlex

2.) Modifying the PdfLinkAnnotations.cs line 120 from new PdfLiteral("<</Type/Border>>"); to new PdfLiteral("<</Type/Border/W 0>>");.

3.) Compiling PDFSharp project

4.) Change your project that uses PDFSharp to use the freshly compiled .dll.

Hope this simple all inclusive explanation helps others.