A shading dictionary specifies details of a particular gradient fill, including the
type of shading to be used, the geometry of the area to be shaded, and the geometry of the gradient fill. Various shading types are available, depending on the value of the dictionary’s ShadingType entry:

• Coons patch meshes (type 6) construct a shading from one or more color
  patches, each bounded by four cubic Bézier curves.

Add support for pivot tables.

When importing a document with a missing "endobj" operator, an exception is thrown: InvalidCastException: 'Unable to cast object of type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfInt' to type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.IndirectObject'.'

PdfFormatProvider: Add support for the "Automatically resize to fit contents" table property.

Currently, the SkiaImageFormatProvider considers the RadFixedPage.Size when creating the image. If the RadFixedPage.CropBox is specified, the developer can control what rectangle of the page to be displayed/printed. However, it is not considered when exporting to an image. Improving the SkiaImageFormatProvider to respect the CropBox as well will give the opportunity to crop just a certain region of the PDF page and save it as an image.

Handle the import of documents with Associated Files (/AF) elements whose content is set to null.

Handle the import of documents with null elements in the Associated Files (/AF) collection.

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

The COUNTA function counts cells containing any type of information, including error values and empty text ("")

https://support.microsoft.com/en-us/office/counta-function-7dc98875-d5c1-46f1-9a82-53f3219e2509 

When importing an existing document which contains a GoToR action, we should preserve the action even after exporting it.

This type of action is currently not supported and a NotSupportedActionException is thrown when accessing such an object.

These exceptions can be handled using the Handling Exceptions mechanism.

Add support for GoToR action

Note: related item: PdfProcessing: Introduce functionality to preserve GoToR actions during import/export

Expose the argument values of existing conditional formatting rules. Currently, the argument values from the SingleArgumentConditionalFormattingRule and DoubleArgumentConditionalFormattingRule classes are internal.

When exporting the PDF content to plain text, the form fields and their values are not extracted. It would be nice to have an option to include the content in the form fields as well.

Introduce Sanitize Document functionality.

https://experienceleague.adobe.com/en/docs/document-cloud-learn/acrobat-learning/advanced-tasks/redact
https://helpx.adobe.com/acrobat/using/removing-sensitive-content-pdfs.html

Export AdditionalActions of the page when merging pages with PdfStreamWriter.

In version 1 there are three profiles that have different levels of detail in their structure: Basic (B), Comfort (C) and Extended (X): https://mind-forms.de/e-rechnung/welches-zugferd-profil-kann-ich-verwenden/ 

One should be able to add hyperlinks.

https://support.microsoft.com/en-us/office/eomonth-function-7314ffa1-2bc9-4005-9d66-f49db127d628 

Provide API for configuring Freeze Panes.