Represents the "Function" entry of the type 1 shading dictionary object.

It is a required entry defined as part of the PDF 1.0 specification.

It contains an array which contains FunctionElements.

If you read the specification you will see that an array of one FunctionElement may be represented as a single FunctionElement rather than an array. However we always present this property as an array to simplify the interface. It is only if you add or remove items in the array, that the underlying representation will be changed.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 79, page 185.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 78, page 230.

The Function entry holds a PDF function object that accepts two input values (x and y coordinates in shading space) and produces one output per color component. The outputs are the color at that position in the shading's color space.