Package org.geotools.styling

Class ContrastEnhancementImpl

Object

ContrastEnhancementImpl

All Implemented Interfaces:

ContrastEnhancement

public class ContrastEnhancementImpl
extends Object
implements ContrastEnhancement

The ContrastEnhancement object defines contrast enhancement for a channel of a false-color image or for a color image. Its format is:

 <xs:element name="ContrastEnhancement">
   <xs:complexType>
     <xs:sequence>
       <xs:choice minOccurs="0">
         <xs:element ref="sld:Normalize"/>
         <xs:element ref="sld:Histogram"/>
       </xs:choice>
       <xs:element ref="sld:GammaValue" minOccurs="0"/>
     </xs:sequence>
   </xs:complexType>
 </xs:element>
 <xs:element name="Normalize">
   <xs:complexType/>
 </xs:element>
 <xs:element name="Histogram">
   <xs:complexType/>
 </xs:element>
 <xs:element name="GammaValue" type="xs:double"/>
 

In the case of a color image, the relative grayscale brightness of a pixel color is used. ?Normalize? means to stretch the contrast so that the dimmest color is stretched to black and the brightest color is stretched to white, with all colors in between stretched out linearly. ?Histogram? means to stretch the contrast based on a histogram of how many colors are at each brightness level on input, with the goal of producing equal number of pixels in the image at each brightness level on output. This has the effect of revealing many subtle ground features. A ?GammaValue? tells how much to brighten (value greater than 1.0) or dim (value less than 1.0) an image. The default GammaValue is 1.0 (no change). If none of Normalize, Histogram, or GammaValue are selected in a ContrastEnhancement, then no enhancement is performed.

Author:

iant

Constructor Summary

Constructors

Constructor	Description
ContrastEnhancementImpl()
ContrastEnhancementImpl(FilterFactory factory)
ContrastEnhancementImpl(FilterFactory factory, Expression gamma, ContrastMethod method)
ContrastEnhancementImpl(FilterFactory factory, ContrastMethod method)
ContrastEnhancementImpl(ContrastEnhancement contrastEnhancement)

Method Summary

Modifier and Type	Method	Description
void	accept(StyleVisitor visitor)	Traversal of the style data structure.
Object	accept(TraversingStyleVisitor visitor, Object extraData)	calls the visit method of a StyleVisitor
void	addOption(String key, Expression value)	Store a vendor option
boolean	equals(Object obj)
Expression	getGammaValue()	How much to brighten (values greater than 1.0) or dim (values less than 1.0) an image.
ContrastMethod	getMethod()	We use a codeList to enable more enchancement type possibilities.
Expression	getOption(String key)
Map<String,Expression>	getOptions()	Return vendor options relating to the enhancement method
int	hashCode()
boolean	hasOption(String key)	check if vendor option key is available
void	setFilterFactory(FilterFactory factory)
void	setGammaValue(Expression gamma)
void	setMethod(ContrastMethod method)	Used to set the contrast enhancement method used.
void	setMethod(ContrastMethodStrategy method)	Convenience method to allow users to pass in a ContrastEnhancementMethod to update Method and Options in one go.
void	setOptions(Map<String,Expression> options)

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ContrastEnhancementImpl

public ContrastEnhancementImpl()

ContrastEnhancementImpl

public ContrastEnhancementImpl(FilterFactory factory)

ContrastEnhancementImpl

public ContrastEnhancementImpl(FilterFactory factory,
                               ContrastMethod method)

ContrastEnhancementImpl

public ContrastEnhancementImpl(ContrastEnhancement contrastEnhancement)

ContrastEnhancementImpl

public ContrastEnhancementImpl(FilterFactory factory,
                               Expression gamma,
                               ContrastMethod method)

Method Detail

setFilterFactory

public void setFilterFactory(FilterFactory factory)

getGammaValue

public Expression getGammaValue()

Description copied from interface: ContrastEnhancement

How much to brighten (values greater than 1.0) or dim (values less than 1.0) an image. The default GammaValue is 1.0 (no change).

Specified by:

getGammaValue in interface ContrastEnhancement

Returns:

Expression, if null a value of 1.0 is assumed indicating no change

setGammaValue

public void setGammaValue(Expression gamma)

Specified by:

setGammaValue in interface ContrastEnhancement

Parameters:

gamma - How much to brighten (greater than 1) or dim (less than 1) this channel; use 1.0 to indicate no change.

getMethod

public ContrastMethod getMethod()

Description copied from interface: ContrastEnhancement

We use a codeList to enable more enchancement type possibilities.

Specified by:

getMethod in interface ContrastEnhancement

accept

public Object accept(TraversingStyleVisitor visitor,
                     Object extraData)

Description copied from interface: ContrastEnhancement

calls the visit method of a StyleVisitor

Specified by:

accept in interface ContrastEnhancement

Parameters:

visitor - the style visitor

accept

public void accept(StyleVisitor visitor)

Description copied from interface: ContrastEnhancement

Traversal of the style data structure.

Specified by:

accept in interface ContrastEnhancement

setMethod

public void setMethod(ContrastMethod method)

Description copied from interface: ContrastEnhancement

Used to set the contrast enhancement method used.

Specified by:

setMethod in interface ContrastEnhancement

getOptions

public Map<String,Expression> getOptions()

Description copied from interface: ContrastEnhancement

Return vendor options relating to the enhancement method

Specified by:

getOptions in interface ContrastEnhancement

Returns:

a Map containing expressions with string keys.

hasOption

public boolean hasOption(String key)

Description copied from interface: ContrastEnhancement

check if vendor option key is available

Specified by:

hasOption in interface ContrastEnhancement

Parameters:

key - - the name of the option to check

Returns:

true if present

getOption

public Expression getOption(String key)

Specified by:

getOption in interface ContrastEnhancement

Returns:

An expression for the matching VendorOption

addOption

public void addOption(String key,
                      Expression value)

Description copied from interface: ContrastEnhancement

Store a vendor option

Specified by:

addOption in interface ContrastEnhancement

Parameters:

key - - the name of the option

value - an expression that evaluates to it's value

setOptions

public void setOptions(Map<String,Expression> options)

Specified by:

setOptions in interface ContrastEnhancement

Parameters:

options - a Map of VendorOptions

setMethod

public void setMethod(ContrastMethodStrategy method)

Description copied from interface: ContrastEnhancement

Convenience method to allow users to pass in a ContrastEnhancementMethod to update Method and Options in one go.

Specified by:

setMethod in interface ContrastEnhancement

Parameters:

method - the ContrastEnhancementMethod that underlies this enhancement

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object