Handle import of documents containing Simple fonts with names of entries in the Encoding`s Differences that are not part of the Adobe Glyph List.

According to the PDF Specification (9.10.2 Mapping Character Codes to Unicode Values) if the name is not part of the list: If these methods fail to produce a Unicode value, there is no way to determine what the character code represents.

The object definitions are split into several lines:

When importing a document containing Outlines (Bookmarks) containing Actions with an empty dictionary:

<</Title(Bookmarks)/Parent .../First .../Last .../Prev .../A<<>>/Count ...>

leads to an exception thrown: System.MissingMethodException: 'Cannot create an abstract class.'

From the PDF specification:

Prev: (Present only if the file has more than one cross-reference section; must not be an indirect reference) The byte offset from the beginning of the file to the beginning of the previous cross-reference section. 

When importing such a document an exception is thrown: System.ArgumentNullException: 'Value cannot be null.

This is Unicode (UTF-16BE) encoding for the Adobe-GB1 character collection; contains mappings for all characters in the GB18030-2000 character set.

Described on page 443 in Pdf Reference 1.7.

RadPdfViewer can not find startxref keyword at the end of a document if the document contains many zero bytes at its end. NotSupportedException is thrown with "Startxref keyword cannot be found" message. 

Workaround: Trim the ending zero bytes before loading the document to the PdfViewer. This is currently noted in the WinForms KB article:
http://www.telerik.com/support/kb/winforms/details/notsupportedexception-startxref-keyword-cannot-be-found-when-loading-pdf-file-in-radpdfviewer-for-winforms

Enable the customers to directly save the document inside PdfViewer to a file or a stream.

Available in LIB Version 2017.3.1225.

The visualizations of all annotations are defined by their normal appearance streams. This is already implemented in RadPdfViewer for the supported annotation types (Link and Widget annotations). It may be easily adopted for not supported annotation types as well.

Available in 2017 R3 Official Release Version.

Currently, all images are decoded and preserved in RGBA format (32 bits for each pixel). However, there are files that optimize their images by preserving them with 1 bit for each pixel. In WPF we may create monochrome System.Windows.Media.ImageSource that would optimize the performance and memory consumption when rendering such images.

Available in R1 2018 Official Release Version.

FixedDocumentPresenter could be TemplateBound to PDFViewer's Background property.

Available in LIB version: 2016.3.1205

"Save As" is common functionality in most of the popular PDF Viewers. It should save the currently loaded document to a file.

Workaround: Currently there is SDK demonstrating how to add such functionality: https://github.com/telerik/xaml-sdk/tree/master/PdfViewer/PdfViewerCustomSaveCommand

Available in R3 2017 Official Release Version.

Implement import and export of content with Type0Font with GBK-EUC-H encoding.

Add support for importing and filling interactive forms.

Interactive Forms content is visualized read-only in RadPdfViewer UI with R1 2017 Release

Available in R3 2017 Official Release Version.

Parsing the wrong content stream in RadPdfViewer results in handled exception and this way some of the PDF content is missing when rendering the page.