CODEWITHSUNDEEP
c#fontspdfsharp
Jules
Jules

Reputation: 7233

How can I extract the Fonts used in a PDF file via PDFSharp?

I am trying to extract the fonts used in a PDF document via PDFSharp (http://www.pdfsharp.net/).

Unfortunately I am not able to do so since I keep on getting strange results and I don't know how to interpret them. In the assembly I have seen classes like PdfFontTable etc, but they are all internal. When decompiling the PdfResources class again everything related to Fonts is internal.

internal PdfResourceMap Fonts

I have tried to access the Resources to get the fonts as:

var reader = Reader.Open(stream, PdfDocumentOpenMode.InformationOnly);
foreach (var page in reader.Pages)
{
    var resources = page.Resources;
    var fonts = resources.Elements.GetValue("/Font");
}

But that gives me an incomprehensible response:

Incomprehensible response from resources

Is there a way to extract the list of fonts used just like I see them in Adobe Acrobat Reader?

Acrobat Reader result

Upvotes: 3

Views: 2249

Answers (2)

Jules
Jules

Reputation: 7233

Eventually I managed to get it to work by registering an IEventListener and handling the TextRenderInfo.

public class FontReader : IEventListener 
{
    private ICollection<FontData> _fonts;

    /// <summary>
    ///     Gets all fonts used in a PdfDocument.
    /// </summary>
    public ICollection<FontData> GetFonts(PdfDocument document)
    {
        _fonts = new List<FontData>();
        var processor = new PdfCanvasProcessor(this);
        for (var i = 1; i <= document.GetNumberOfPages(); i++)
        {
            var page = document.GetPage(i);
            processor.ProcessPageContent(page);
        }

        return _fonts;
    }

    public void EventOccurred(IEventData data, EventType type)
    {
       if (!(data is TextRenderInfo)) return;

       var font = ((TextRenderInfo)data).GetFont();
       var name = font.GetFontProgram().GetFontNames().GetFontName();
       var type = font.GetPdfObject().GetAsName(PdfName.Subtype).GetValue();
       ...
       _fonts.Add(...);
    }
}

Upvotes: 1

Tichy
Tichy

Reputation: 21

There is no direct API way to query the fonts. But it is possible to query the internal document data structures. The following code works and returns a list with fonts.

List<string> fonts = new List<string>();
PdfDocument pdfDoc = PdfReader.Open("YourFileName.pdf");
foreach (PdfObject obj in pdfDoc.Internals.GetAllObjects())
{
    if ("dictionary" == obj.Internals.TypeID)
    {
        for (int i = 0; i < ((PdfDictionary)obj).Elements.Count; ++i)
        {
            if (((PdfDictionary)obj).Elements.ContainsKey("/BaseFont"))
            {
                PdfItem item = ((PdfDictionary)obj).Elements.GetValue("/BaseFont");
                string fontname = item.ToString();
                int idx = fontname.IndexOf('+');
                if (idx > 0)
                {
                    fontname = fontname.Substring(idx + 1).Trim();
                    if (!fonts.Contains(fontname))
                        fonts.Add(fontname);
                }
            }
        }
    }
}

Upvotes: 2

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