CHAPTER 3
170
Syntax
To explain the relationship between
Domain
,
Encode
,
Size
,
Decode
, and
Range
,
we use the following notation:
y
=
Interpolate
(
x
,
x
min
,
x
max
,
y
min
,
y
max
)
y
max
–
y
min
⎞
⎛
----------------------------
⎟
=
y
min
+
⎜
(
x
–
x
min
) ×
x
max
–
x
min
⎠
⎝
For a given value of
x,
Interpolate calculates the
y
value on the line defined by the
two points (x
min
,
y
min
) and (x
max
,
y
max
).
TABLE 3.36 Additional entries specific to a type 0 function dictionary
KEY
TYPE
VALUE
Size
array
integer
(Required)
An array of
m
positive integers specifying the number of samples
in each input dimension of the sample table.
(Required)
The number of bits used to represent each sample. (If the function
has multiple output values, each one occupies
BitsPerSample
bits.) Valid
values are 1, 2, 4, 8, 12, 16, 24, and 32.
(Optional)
The order of interpolation between samples. Valid values are 1 and
3, specifying linear and cubic spline interpolation, respectively. (See imple-
(Optional)
An array of 2
×
m
numbers specifying the linear mapping of input
values into the domain of the function’s sample table. Default value:
[ 0 (Size
0
−
1) 0 (Size
1
−
1) … ]
.
(Optional)
An array of 2
×
n
numbers specifying the linear mapping of sam-
ple values into the range appropriate for the function’s output values. Default
value: same as the value of
Range
.
(Optional)
Other attributes of the stream that provides the sample values, as
appropriate (see Table 3.4 on page 62).
BitsPerSample
Order
integer
Encode
array
Decode
array
other stream
attributes
(various)
When a sampled function is called, each input value
x
i
, for 0
≤
i
<
m,
is clipped to
the domain:
x
i
′
=
min
(
max
(
x
i
,
Domain
2i
) ,
Domain
2i
+
1
)