org.apache.pdfbox.pdmodel.common.function

Class PDFunction

java.lang.Object

org.apache.pdfbox.pdmodel.common.function.PDFunction

All Implemented Interfaces:

COSObjectable

Direct Known Subclasses:

PDFunctionType0, PDFunctionType2, PDFunctionType3, PDFunctionType4, PDFunctionTypeIdentity

public abstract class PDFunction
extends Object
implements COSObjectable

This class represents a function in a PDF document.

Author:

Ben Litchfield

Constructor Summary

Constructors

Constructor and Description
PDFunction(COSBase function) Constructor.

Method Summary

Modifier and Type	Method and Description
protected float[]	clipToRange(float[] inputValues) Clip the given input values to the ranges.
protected float	clipToRange(float x, float rangeMin, float rangeMax) Clip the given input value to the given range.
static PDFunction	create(COSBase function) Create the correct PD Model function based on the COS base function.
COSArray	eval(COSArray input) Deprecated. Replaced by eval(float[] input)
abstract float[]	eval(float[] input) Evaluates the function at the given input.
COSDictionary	getCOSObject() Returns the stream.
PDRange	getDomainForInput(int n) This will get the range for a certain input parameter.
abstract int	getFunctionType() Returns the function type.
int	getNumberOfInputParameters() This will get the number of input parameters that have a domain specified.
int	getNumberOfOutputParameters() This will get the number of output parameters that have a range specified.
protected PDStream	getPDStream() Returns the underlying PDStream.
PDRange	getRangeForOutput(int n) This will get the range for a certain output parameters.
protected COSArray	getRangeValues() Returns all ranges for the output values as COSArray .
protected float	interpolate(float x, float xRangeMin, float xRangeMax, float yRangeMin, float yRangeMax) For a given value of x, interpolate calculates the y value on the line defined by the two points (xRangeMin , xRangeMax ) and (yRangeMin , yRangeMax ).
void	setDomainValues(COSArray domainValues) This will set the domain values.
void	setRangeValues(COSArray rangeValues) This will set the range values.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

PDFunction

public PDFunction(COSBase function)

Constructor.

Parameters:

function - The function stream.

Method Detail

getFunctionType

public abstract int getFunctionType()

Returns the function type. Possible values are: 0 - Sampled function 2 - Exponential interpolation function 3 - Stitching function 4 - PostScript calculator function

Returns:

the function type.

getCOSObject

public COSDictionary getCOSObject()

Returns the stream.

Specified by:

getCOSObject in interface COSObjectable

Returns:

The stream for this object.

getPDStream

protected PDStream getPDStream()

Returns the underlying PDStream.

Returns:

The stream.

create

public static PDFunction create(COSBase function)
                         throws IOException

Create the correct PD Model function based on the COS base function.

Parameters:

function - The COS function dictionary.

Returns:

The PDModel Function object.

Throws:

IOException - If we are unable to create the PDFunction object.

getNumberOfOutputParameters

public int getNumberOfOutputParameters()

This will get the number of output parameters that have a range specified. A range for output parameters is optional so this may return zero for a function that does have output parameters, this will simply return the number that have the range specified.

Returns:

The number of output parameters that have a range specified.

getRangeForOutput

public PDRange getRangeForOutput(int n)

This will get the range for a certain output parameters. This is will never return null. If it is not present then the range 0 to 0 will be returned.

Parameters:

n - The output parameter number to get the range for.

Returns:

The range for this component.

setRangeValues

public void setRangeValues(COSArray rangeValues)

This will set the range values.

Parameters:

rangeValues - The new range values.

getNumberOfInputParameters

public int getNumberOfInputParameters()

This will get the number of input parameters that have a domain specified.

Returns:

The number of input parameters that have a domain specified.

getDomainForInput

public PDRange getDomainForInput(int n)

This will get the range for a certain input parameter. This is will never return null. If it is not present then the range 0 to 0 will be returned.

Parameters:

n - The parameter number to get the domain for.

Returns:

The domain range for this component.

setDomainValues

public void setDomainValues(COSArray domainValues)

This will set the domain values.

Parameters:

domainValues - The new domain values.

eval

@Deprecated
public COSArray eval(COSArray input)
                          throws IOException

Deprecated. Replaced by eval(float[] input)

Parameters:

input - The array of input values for the function.

Returns:

The of outputs the function returns based on those inputs.

Throws:

IOException - if something went wrong.

eval

public abstract float[] eval(float[] input)
                      throws IOException

Evaluates the function at the given input. ReturnValue = f(input)

Parameters:

input - The array of input values for the function. In many cases will be an array of a single value, but not always.

Returns:

The of outputs the function returns based on those inputs. In many cases will be an array of a single value, but not always.

Throws:

IOException - an IOExcpetion is thrown if something went wrong processing the function.

getRangeValues

protected COSArray getRangeValues()

Returns all ranges for the output values as COSArray . Required for type 0 and type 4 functions

Returns:

the ranges array.

clipToRange

protected float[] clipToRange(float[] inputValues)

Clip the given input values to the ranges.

Parameters:

inputValues - the input values

Returns:

the clipped values

clipToRange

protected float clipToRange(float x,
                            float rangeMin,
                            float rangeMax)

Clip the given input value to the given range.

Parameters:

x - the input value

rangeMin - the min value of the range

rangeMax - the max value of the range

Returns:

the clipped value

interpolate

protected float interpolate(float x,
                            float xRangeMin,
                            float xRangeMax,
                            float yRangeMin,
                            float yRangeMax)

For a given value of x, interpolate calculates the y value on the line defined by the two points (xRangeMin , xRangeMax ) and (yRangeMin , yRangeMax ).

Parameters:

x - the to be interpolated value.

xRangeMin - the min value of the x range

xRangeMax - the max value of the x range

yRangeMin - the min value of the y range

yRangeMax - the max value of the y range

Returns:

the interpolated y value

toString

public String toString()

Overrides:

toString in class Object