| ArrayFunction | An array function is not one of the built-in PDF function types. | 
| AxialShading | Implementation of Type 2 shadings, which vary color along a linear axis. | 
| FunctionShading | Function-based (type 1) shadings
 x,y values in shading space are just passed to the function and the returned color value is plotted. | 
| InterpolationFunction | Type 2 exponential interpolation functions. | 
| RadialShading | A concrete subclass of PDFShadingPattern which implements pdf radial (type 3) shadings. | 
| SampledFunction | Type 0 sampled functions. | 
| ShadingPattern | PDFShadingPattern. | 
| StitchingFunction | A Stitching function is a function that contains an array of subfunctions. | 
| TilingPattern |  |