By specification, the last line of the file contains only the end-of-file marker, %%EOF. If the file contains many trailing bytes at its end, a NotSupportedException: 'StartXRef keyword cannot be found.', is thrown.

Workaround: Trim any content after the end-of-file marker (see FixInvalidEndOfFile). 

Current implementation relies on valid cross-reference offsets in the PDF documents so that PDF objects are easily found and parsed. However, we can implement a mechanism for repairing documents with invalid cross-reference tables.

The attached project shows how to repair the simplest case of cross-reference table by using RepairDocumentWithSimpleCrossReferenceTable method.

RadPdfProcessing cannot 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 PdfProcessing. Example showing this approach can be found in the following KB article:
http://www.telerik.com/support/kb/winforms/details/notsupportedexception-startxref-keyword-cannot-be-found-when-loading-pdf-file-in-radpdfviewer-for-winforms

When importing such documents an InvalidDataException (Unknown compression method <method-name>) is thrown.

According to the current .ZIP File Format Specification these methods are 7, 11, 13, 15, and 17.

Compression method:

        0 - The file is stored (no compression)
        1 - The file is Shrunk
        2 - The file is Reduced with compression factor 1
        3 - The file is Reduced with compression factor 2
        4 - The file is Reduced with compression factor 3
        5 - The file is Reduced with compression factor 4
        6 - The file is Imploded
        7 - Reserved for Tokenizing compression algorithm
        8 - The file is Deflated
        9 - Enhanced Deflating using Deflate64(tm)
       10 - PKWARE Data Compression Library Imploding (old IBM TERSE)
       11 - Reserved by PKWARE
       12 - File is compressed using BZIP2 algorithm
       13 - Reserved by PKWARE
       14 - LZMA
       15 - Reserved by PKWARE
       16 - IBM z/OS CMPSC Compression
       17 - Reserved by PKWARE
       18 - File is compressed using IBM TERSE (new)
       19 - IBM LZ77 z Architecture 
       20 - deprecated (use method 93 for zstd)
       93 - Zstandard (zstd) Compression 
       94 - MP3 Compression 
       95 - XZ Compression 
       96 - JPEG variant
       97 - WavPack compressed data
       98 - PPMd version I, Rev 1
       99 - AE-x encryption marker (see APPENDIX E)

When importing a document containing an inline image that starts with spaces a NullReferenceException is thrown.

Implement async PDF conversion from RadFlowDocument and Workbook

By specification, the URI property of URI Actions is encoded in 7-bit ASCII string. For this reason, our current implementation relies on that the property will be of type PdfLiteralString. However, in cases such as password-encrypted documents, the property may be encoded with PdfHexString which leads to InvalidCastException: 'Unable to cast object of type Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfHexString' to type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfLiteralString'.', on document import.

Add a PDF document validator to validate (before the import of the document) an existing PDF document.

According to the PDF specification (Adobe® Portable Document Format Version 1.7), the appearance dictionary is optional and it is specifying how the annotation is presented visually on the page.

Exceptions thrown:

InvalidCastException: 'Unable to cast object of type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfNull' to type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Annotations.Appearance'.'

NullReferenceException: 'Object reference not set to an instance of an object.'

When the document contains Simple Font with predefined encoding and no ToUnicode mapping the text should be extracted with the following algorithm:

• Map the character code to a character name according to the font’s Differences array.
• Look up the character name in the Adobe Glyph List to obtain the corresponding Unicode value. 
  

Currently, the PdfProcessing library doesn't map the character code properly which leads to wrongly encoded text content.

Writing a page to a stream with resources, defined with names including space or dash characters, are not exported using an escape sequence.

This API should provide a method for removing all fields and widgets in the document and draw the default widget appearance in place of the removed widgets.

WORKAROUND: Sample implementation for flattening form fields may be seen in the FlattenFormFields method from the attached demo project.

Adding a table with the same code leads to different results 

When adding 10 identical tables onе or more have missing rows at the bottom. The seems to be caused by the text measurement. 

The executing of the PostScriptReader`s Read method takes a lot of time when iterating content streams with many Path geometries.

When exporting TextBoxField with a Simple font and a Differences array defined in the Encoding, the CharCodes covered by this array are incorrectly mapped to glyph indices.

When a TrueType font is defined, the mapping of character codes to glyph indices depends on the built-in cmap table mappings defined in the font and the Encoding property defined in the PDF dictionary.

However, the current implementation maps all characters with cmap tables for Microsoft Symbolic and Macintosh Roman, which causes incorrect mapping results, e.g. space characters are mapped to an Ê glyph.

The issue is also described in the following public item: TryGetCharCode for OpenTypeFont uses wrong cmap and returns wrong charcode.

Workaround: Change the font  of the TextBoxField's widget appearance:
foreach (var widget in field.Widgets)
{
    widget.TextProperties.Font = FontsRepository.Helvetica;
}

There are many instances of the internal Transition, State and ImageXObject classes.

Currently, this missing functionality may be workaround by either drawing the headers and footers with FixedContentEditor or by using RadWordsProcessing PDF export.

The PDF model allows actions to be defined for widgets using the optional /A entry. 

Implement GetColor method for Indexed color space