Interface ContrastEnhancement
- All Known Implementing Classes:
ContrastEnhancementImpl
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.
- Since:
- GeoAPI 2.2
- Author:
- Open Geospatial Consortium, Ian Turton, CCG, Johann Sorel (Geomatys)
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Method Summary
Modifier and TypeMethodDescriptionvoid
accept
(StyleVisitor visitor) Traversal of the style data structure.accept
(TraversingStyleVisitor visitor, Object extraData) calls the visit method of a StyleVisitorvoid
addOption
(String key, Expression value) Store a vendor optionHow much to brighten (values greater than 1.0) or dim (values less than 1.0) an image.We use a codeList to enable more enchancement type possibilities.Return vendor options relating to the enhancement methodboolean
check if vendor option key is availablevoid
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 aContrastMethodStrategy
to updatesetMethod(org.geotools.api.style.ContrastMethod)
andsetOptions(java.util.Map<java.lang.String, org.geotools.api.filter.expression.Expression>)
in one go.void
setOptions
(Map<String, Expression> options)
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Method Details
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getMethod
ContrastMethod getMethod()We use a codeList to enable more enchancement type possibilities. -
setMethod
Used to set the contrast enhancement method used. -
setGammaValue
- Parameters:
gamma
- How much to brighten (greater than 1) or dim (less than 1) this channel; use 1.0 to indicate no change.
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getGammaValue
Expression getGammaValue()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).- Returns:
- Expression, if
null
a value of 1.0 is assumed indicating no change
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accept
calls the visit method of a StyleVisitor- Parameters:
visitor
- the style visitor
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getOptions
Map<String,Expression> getOptions()Return vendor options relating to the enhancement method- Returns:
- a Map containing expressions with string keys.
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hasOption
check if vendor option key is available- Parameters:
key
- - the name of the option to check- Returns:
- true if present
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addOption
Store a vendor option- Parameters:
key
- - the name of the optionvalue
- an expression that evaluates to it's value
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accept
Traversal of the style data structure. -
setOptions
- Parameters:
options
- a Map of VendorOptions
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getOption
- Returns:
- An expression for the matching VendorOption
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setMethod
Convenience method to allow users to pass in aContrastMethodStrategy
to updatesetMethod(org.geotools.api.style.ContrastMethod)
andsetOptions(java.util.Map<java.lang.String, org.geotools.api.filter.expression.Expression>)
in one go.- Parameters:
method
- theContrastMethodStrategy
that underlies this enhancement
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