Table 79 – Additional Entries Specific to a Type 1 Shading Dictionary

Key

Type

Value

Domain

array

(Optional) An array of four numbers [ x min x max y min y max ] specifying the rectangular domain of coordinates over which the colour function(s) are defined. Default value: [ 0.0 1.0 0.0 1.0 ].

Matrix

array

(Optional) An array of six numbers specifying a transformation matrix mapping the coordinate space specified by the Domain entry into the shading’s target coordinate space.

NOTE To map the domain rectangle [ 0.0 1.0 0.0 1.0 ] to a 1-inch square with lower-left corner at coordinates (100, 100) in default user space, the Matrix value would be [ 72 0 0 72 100 100 ].

Default value: the identity matrix [ 1 0 0 1 0 0 ].

Function

function

(Required) A 2-in, n-out function or an array of n 2-in, 1-out functions (where n is the number of colour components in the shading dictionary’s colour space). Each function’s domain shall be a superset of that of the shading dictionary. If the value returned by the function for a given colour component is out of range, it shall be adjusted to the nearest valid value.