Graphics Programs Reference
In-Depth Information
Figure 5-11. Transparency in PDF
We consider just Axial and Radial shadings.
Patterns are invoked by changing to the
/Pattern
color space using the
cs
operator,
then using the
scn
operator to select a named pattern. Patterns are listed by name in
the
/Pattern
dictionary in the page's resources. For example:
/Pattern
<<
/GradientShading
Our name for the pattern
<<
/Type /Pattern
/PatternType 2
A shading pattern
/Shading
<<
/ColorSpace /DeviceGray
/ShadingType 2
A linear shading
/Function << /FunctionType 2 /N 1 /Domain [0 1] >>
/Coords [150 200 450 500]
Coordinates of start and end of gradient
/Extend [true true]
>>
>>
>>
