org.apache.fop.pdf
Class PDFFunction
- PDFWritable
class representing a PDF Function.
PDF Functions represent parameterized mathematical formulas and
sampled representations with
arbitrary resolution. Functions are used in two areas: device-dependent
rasterization information for halftoning and transfer
functions, and color specification for smooth shading (a PDF 1.3 feature).
All PDF Functions have a FunctionType (0,2,3, or 4), a Domain, and a Range.
protected int | bitsPerSample - Required for Type 0: Number of Bits used to represent each sample value.
|
protected List | bounds - Optional for Type 3: An array of (k-1) Doubles that,
in combination with Domain, define the intervals to which
each function from the Functions array apply.
|
protected List | cOne - Required For Type 2: An Array of n Doubles defining
the function result when x=1.
|
protected List | cZero - Required For Type 2: An Array of n Doubles defining
the function result when x=0.
|
protected List | decode - Optional for Type 0: A 2 * n array of Doubles which provides
a linear mapping of sample values to the range.
|
protected List | domain - Required: 2 * m Array of Double numbers which are possible inputs to the function
|
protected List | encode - Optional for Type 0: A 2 * m array of Doubles which provides a
linear mapping of input values to the domain.
|
protected List | filter - Required (possibly) For Type 0: A vector of Strings for the
various filters to be used to decode the stream.
|
protected StringBuffer | functionDataStream - Required For Type 4: Postscript Calculator function
composed of arithmetic, boolean, and stack operators + boolean constants
|
protected int | functionType - Required: The Type of function (0,2,3,4) default is 0.
|
protected List | functions - Required for Type 3: An vector of PDFFunctions which
form an array of k single input functions making up
the stitching function.
|
protected double | interpolationExponentN - Required for Type 2: The interpolation exponent.
|
protected int | order - Optional for Type 0: order of interpolation between samples.
|
protected List | range - Required: 2 * n Array of Double numbers which are possible outputs to the function
|
protected List | size - Required: Array containing the Integer size of the Domain and Range, respectively.
|
PDFFunction(int theFunctionType, List theDomain, List theRange, List theFunctions, List theBounds, List theEncode) - create an complete Function object of Type 3, a Stitching function.
|
PDFFunction(int theFunctionType, List theDomain, List theRange, List theCZero, List theCOne, double theInterpolationExponentN) - create an complete Function object of Type 2, an Exponential Interpolation function.
|
PDFFunction(int theFunctionType, List theDomain, List theRange, List theSize, int theBitsPerSample, int theOrder, List theEncode, List theDecode, StringBuffer theFunctionDataStream, List theFilter) - create an complete Function object of Type 0, A Sampled function.
|
PDFFunction(int theFunctionType, List theDomain, List theRange, StringBuffer theFunctionDataStream) - create an complete Function object of Type 4, a postscript calculator function.
|
boolean | equals(Object obj) - Check if this function is equal to another object.
|
byte[] | toPDF() - represent as PDF.
|
encode , encodeString , encodeText , formatDateTime , formatObject , getDocument , getDocumentSafely , getGeneration , getObjectID , getObjectNumber , hasObjectNumber , makeReference , output , referencePDF , setDocument , setObjectNumber , toInlinePDFString , toPDF , toPDFString |
bitsPerSample
protected int bitsPerSample
Required for Type 0: Number of Bits used to represent each sample value.
Limited to 1,2,4,8,12,16,24, or 32
bounds
protected List bounds
Optional for Type 3: An array of (k-1) Doubles that,
in combination with Domain, define the intervals to which
each function from the Functions array apply. Bounds
elements must be in order of increasing magnitude,
and each value must be within the value of Domain.
k is the number of functions.
If you pass null, it will output (1/k) in an array of k-1 elements.
This makes each function responsible for an equal amount of the stitching function.
It makes the gradient even.
cOne
protected List cOne
Required For Type 2: An Array of n Doubles defining
the function result when x=1. Default is [1].
cZero
protected List cZero
Required For Type 2: An Array of n Doubles defining
the function result when x=0. Default is [0].
decode
protected List decode
Optional for Type 0: A 2 * n array of Doubles which provides
a linear mapping of sample values to the range. Defaults to Range.
domain
protected List domain
Required: 2 * m Array of Double numbers which are possible inputs to the function
encode
protected List encode
Optional for Type 0: A 2 * m array of Doubles which provides a
linear mapping of input values to the domain.
Required for Type 3: A 2 * k array of Doubles that, taken
in pairs, map each subset of the domain defined by Domain
and the Bounds array to the domain of the corresponding function.
Should be two values per function, usually (0,1),
as in [0 1 0 1] for 2 functions.
filter
protected List filter
Required (possibly) For Type 0: A vector of Strings for the
various filters to be used to decode the stream.
These are how the string is compressed. Flate, LZW, etc.
functionDataStream
protected StringBuffer functionDataStream
Required For Type 4: Postscript Calculator function
composed of arithmetic, boolean, and stack operators + boolean constants
functionType
protected int functionType
Required: The Type of function (0,2,3,4) default is 0.
functions
protected List functions
Required for Type 3: An vector of PDFFunctions which
form an array of k single input functions making up
the stitching function.
interpolationExponentN
protected double interpolationExponentN
Required for Type 2: The interpolation exponent.
Each value x will return n results.
Must be greater than 0.
order
protected int order
Optional for Type 0: order of interpolation between samples.
Limited to linear (1) or cubic (3). Default is 1
range
protected List range
Required: 2 * n Array of Double numbers which are possible outputs to the function
size
protected List size
Required: Array containing the Integer size of the Domain and Range, respectively.
Note: This is really more like two seperate integers, sizeDomain, and sizeRange,
but since they're expressed as an array in PDF, my implementation reflects that.
PDFFunction
public PDFFunction(int theFunctionType,
List theDomain,
List theRange,
List theFunctions,
List theBounds,
List theEncode)
create an complete Function object of Type 3, a Stitching function.
Use null for an optional object parameter if you choose not to use it.
For optional int parameters, pass the default.
theFunctionType
- This is the function type. It should be 3,
for a stitching function.theDomain
- List objects of Double objects.
This is the domain of the function.
See page 264 of the PDF 1.3 Spec.theRange
- List objects of Double objects.
This is the Range of the function.
See page 264 of the PDF 1.3 Spec.theFunctions
- A List of the PDFFunction objects that the stitching function stitches.
This attributed is required.
It is described on page 269 of the PDF spec.theBounds
- This is a vector of Doubles representing the numbers that,
in conjunction with Domain define the intervals to which each function from
the 'functions' object applies. It must be in order of increasing magnitude,
and each must be within Domain.
It basically sets how much of the gradient each function handles.
This attributed is required.
It's described on page 269 of the PDF 1.3 spec.theEncode
- List objects of Double objects.
This is the linear mapping of input values intop the domain
of the function's sample table. Default is hard to represent in
ascii, but basically [0 (Size0 1) 0 (Size1 1)...].
This attribute is required.
See page 270 in the PDF 1.3 spec.
PDFFunction
public PDFFunction(int theFunctionType,
List theDomain,
List theRange,
List theCZero,
List theCOne,
double theInterpolationExponentN)
create an complete Function object of Type 2, an Exponential Interpolation function.
Use null for an optional object parameter if you choose not to use it.
For optional int parameters, pass the default.
theFunctionType
- The type of the function, which should be 2.theDomain
- List objects of Double objects.
This is the domain of the function.
See page 264 of the PDF 1.3 Spec.theRange
- List of Doubles that is the Range of the function.
See page 264 of the PDF 1.3 Spec.theCZero
- This is a vector of Double objects which defines the function result
when x=0.
This attribute is optional.
It's described on page 268 of the PDF 1.3 spec.theCOne
- This is a vector of Double objects which defines the function result
when x=1.
This attribute is optional.
It's described on page 268 of the PDF 1.3 spec.theInterpolationExponentN
- This is the inerpolation exponent.
This attribute is required.
PDF Spec page 268
PDFFunction
public PDFFunction(int theFunctionType,
List theDomain,
List theRange,
List theSize,
int theBitsPerSample,
int theOrder,
List theEncode,
List theDecode,
StringBuffer theFunctionDataStream,
List theFilter)
create an complete Function object of Type 0, A Sampled function.
Use null for an optional object parameter if you choose not to use it.
For optional int parameters, pass the default.
theFunctionType
- This is the type of function (0,2,3, or 4).
It should be 0 as this is the constructor for sampled functions.theDomain
- List objects of Double objects.
This is the domain of the function.
See page 264 of the PDF 1.3 Spec.theRange
- List objects of Double objects.
This is the Range of the function.
See page 264 of the PDF 1.3 Spec.theSize
- A List object of Integer objects.
This is the number of samples in each input dimension.
I can't imagine there being more or less than two input dimensions,
so maybe this should be an array of length 2.
See page 265 of the PDF 1.3 Spec.theBitsPerSample
- An int specifying the number of bits
used to represent each sample value.
Limited to 1,2,4,8,12,16,24 or 32.
See page 265 of the 1.3 PDF Spec.theOrder
- The order of interpolation between samples. Default is 1 (one). Limited
to 1 (one) or 3, which means linear or cubic-spline interpolation.
This attribute is optional.
See page 265 in the PDF 1.3 spec.theEncode
- List objects of Double objects.
This is the linear mapping of input values intop the domain
of the function's sample table. Default is hard to represent in
ascii, but basically [0 (Size0 1) 0 (Size1 1)...].
This attribute is optional.
See page 265 in the PDF 1.3 spec.theDecode
- List objects of Double objects.
This is a linear mapping of sample values into the range.
The default is just the range.
This attribute is optional.
Read about it on page 265 of the PDF 1.3 spec.theFunctionDataStream
- The sample values that specify
the function are provided in a stream.
This is optional, but is almost always used.
Page 265 of the PDF 1.3 spec has more.theFilter
- This is a vector of String objects which are the various filters that
have are to be applied to the stream to make sense of it. Order matters,
so watch out.
This is not documented in the Function section of the PDF 1.3 spec,
it was deduced from samples that this is sometimes used, even if we may never
use it in FOP. It is added for completeness sake.
PDFFunction
public PDFFunction(int theFunctionType,
List theDomain,
List theRange,
StringBuffer theFunctionDataStream)
create an complete Function object of Type 4, a postscript calculator function.
Use null for an optional object parameter if you choose not to use it.
For optional int parameters, pass the default.
theFunctionType
- The type of function which should be 4, as this is
a Postscript calculator functiontheDomain
- List object of Double objects.
This is the domain of the function.
See page 264 of the PDF 1.3 Spec.theRange
- List object of Double objects.
This is the Range of the function.
See page 264 of the PDF 1.3 Spec.theFunctionDataStream
- This is a stream of arithmetic,
boolean, and stack operators and boolean constants.
I end up enclosing it in the '{' and '}' braces for you, so don't do it
yourself.
This attribute is required.
It's described on page 269 of the PDF 1.3 spec.
equals
public boolean equals(Object obj)
Check if this function is equal to another object.
This is used to find if a particular function already exists
in a document.
- true if the functions are equal
toPDF
public byte[] toPDF()
represent as PDF. Whatever the FunctionType is, the correct
representation spits out. The sets of required and optional
attributes are different for each type, but if a required
attribute's object was constructed as null, then no error
is raised. Instead, the malformed PDF that was requested
by the construction is dutifully output.
This policy should be reviewed.
- toPDF in interface PDFObject
Copyright 1999-2007 The Apache Software Foundation. All Rights Reserved.