This will allow the import of Tensor-product patch mesh gradients. Currently, importing documents that contain ShadingType 7 results in NotSupportedShadingTypeException.

This type of shading is not supported in the current version and a NotSupportedException is thrown when importing documents containing it.

The exception can be suppressed using the Exception Handling mechanism of PdfProcessing.

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 ShadingType 1.

Expose internal GrayColor object.

Opening a file where there is a format string with modificator [Color11] causes an ArgumentException "Invalid modificator" This prevents the file from opening.