Exported protected document containing SignatureField can not be opened even if the correct password is used. The same behavior is reproduced with empty document (without pages).

Implement functionality to support scenario when a document which already has a signature to be signed again or add two or more signatures.

The appearance dictionary specifies how the annotation is presented visually on the page. If the appearance missing or is empty in PDF document NullReferenceException is thrown on import. 

Currently, signature flags, represented by the 'SigFlags' optional entry, are not imported and exported, and there is no API for setting them.
As a result, documents signed with RadPdfProcessing (or with RadPdfViewer) appear in Adobe Reader without the blue document message bar at the top (the analogue of the RadPdfViewer's SignaturePanel).

If the API is supported, setting the flag to 1 or 3 would ensure that the message bar would be visualized in Adobe Reader.

When importing document with predefined ToUnicode CMaps (e.g. Identity-H), an InvalidCastException is thrown with cause: 

Unable to cast object of type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfName' to type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.CMaps.ToUnicodeCMap'.

When documents are exported to PDF, the creation date and modification date are not expected, or, when the time zone is with negative offset, the documents are invalid (detected by validation tools).

Some customers need to export a single page of the PDF document to plain text. Expose such a possibility so the customers don't need to export the whole document.

The tj operator is responsible for drawing text content. When such operator is left empty, the import throws NullReferenceException because of the missing operands.

Available in LIB Version 2018.3.1022.

When the string contained in a PdfHexString instance is empty, invoking ToString() leads to IndexOutOfRangeException.

Available in R3 2018 SP1 release version.

This type of fields is currently not supported: https://feedback.telerik.com/Project/184/Feedback/Details/249205 . However, the fields can be skipped and the other content can be imported without throwing an exception.

Fix available in R3 2018 SP1 release.

A font descriptor can be used by several fonts. However, when first a TrueType font is imported, later trying to import a Cid font leads to InvalidCastException with the message: "Unable to cast object of type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.FontDescriptor' to type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.CidFontDescriptor'."

Fix available in R3 2018 SP1 release.

This happens only in cases when the Radio flag is not set and there are multiple widgets with different "ON" state names.

While signing a document in Adobe Reader, the users can lock the document fields from editing. Expose a similar functionality.

The feature is described by the FieldMDP transform method, described on page 736 from the Pdf Reference 1.7

The signature field preserves information about the time of signing through the TimeOfSigning property of Signature.Properties. However, the DateTime object doesn't keep info about the time zone the document has been signed in. Some customers need to obtain this information.

When exporting a document with the .NET Framework implementation, only subsets of the used fonts are embedded in the document. 

This is currently not available in the Silverlight implementation, and it most probably won't be available in the .NET Standard implementation, as the current implementation is dependent on the WPF font classes.

Provide API to plug similar logic when using different platforms as well.
This item wil handle the TrueType OpenType Font format. For the Compact Font Format (CFF) please follow: Export subset of Compact Font Format (CFF) fonts for platforms different than .NET Framework

We should implement the logic for getting character codes from Unicode when using CFFFontSource.

Workaround: The font may be changed by creating a similar font with FontsRepository.TryCreateFont(...) method.
Telerik.Windows.Documents.Fixed.Model.Fonts.FontsRepository.RegisterFont(new Telerik.Documents.Core.Fonts.FontFamily("Arial"), Telerik.Documents.Core.Fonts.FontStyles.Normal, Telerik.Documents.Core.Fonts.FontWeights.Normal, fontData); // fontData is a byte[] keeping the font definition

FontBase font;
bool hasCreatedFont = FontsRepository.TryCreateFont(new FontFamily("Arial"), out font);
 
foreach (TextField field in document.AcroForm.FormFields.OfType<TextField>())
{
    if (hasCreatedFont)
    {
        foreach (var widget in field.Widgets)
        {
            widget.TextProperties.Font = font;
        }
 
        field.TextProperties.Font = font;
    }
}

For instance, we may implement WritePageAsync method in addition to the existing WritePage method. This is a similar scenario as in System.IO.StreamWriter class which has WriteLine and WriteLineAsync methods.

The exception is reproduced only with specific custom fonts and is thrown by the ComputeSubset() method of the GlyphTypeface class with the following message: "file does not conform to the expected file format specification". However, we can handle the exception and export the font data using the base class.

Fix available in LIB Version 2018.2.828.

The exception is thrown by System.Linq.Enumerable.Max method during the CidSet calculations.

Fix available in LIB Version 2018.2.730.

ArgumentException is thrown while importing a choice field whose value is an empty string. Instead, the empty string should be imported.