While PDFViewer for WPF and Silverlight aims to provide a full-featured PDF viewer, it supports a subset of the PDF 1.5 standard and so, like most PDF viewers on the market, does have its limitations.

The limitations focus in two areas: fonts and images.

Fonts

C1PDFViewer supports the following font types:

• Embedded TrueType fonts: These are fonts specified using the "FontFile2" mechanism in PDF.
• OpenType fonts: These are successors of the TrueType fonts, and provide cross-platform compatibility as well as extensive language support.
• Silverlight fonts: This includes all font families supported by Silverlight.
• PDF base fonts: This includes fonts built into Adobe Acrobat such as Helvetica, Times, and Symbol.

The C1PdfViewer control does not support other font types available in the PDF specification, including Adobe Type 1 fonts (specified using the "FontFile" mechanism in the PDF file).

Documents that use non-supported fonts will still render, but the formatting will be incorrect (for example, the document may show overlapping text).

Images

C1PDFViewer supports most common image types, including all binary stream formats supported by Silverlight as well as deflated streams of several types (RGB, Monochrome, and several common indexed formats).

The C1PdfViewer control does not support some rare formats such as deflated JPG streams, or advanced features such as custom color spaces or halftones. Note that scanned PDF files may contain TIFF data which the C1PdfViewer control is currently not capable of rendering.