Last time we attempted this the <Viewbox> contents would not render and were empty upon xaml to pdf output. It would be great if you had this feature and we could move completely away from raster output to PDF for controls that contain Viewboxes. Otherwise we have really liked the PDF's created by the tool, the vector output is sharp as expected.
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.
This operator is used for drawing shading patterns.
Currently, PdfStreamWriter writes only PDF pages. If we implement API for merging multiple pages or whole documents we would be able to preserve links between pages (which are currently being corrupted). Merging whole documents would also allow preserving document properties (bookmarks, interactive forms, ...). For a more detailed list of the unsupported document properties you can refer to our documentation: https://docs.telerik.com/devtools/document-processing/libraries/radpdfprocessing/formats-and-conversion/pdf/pdfstreamwriter/features. We may also implement API for adding initial document properties from some existing PDF file.