Package org.geotools.api.style

Interface ContrastEnhancement

  • All Known Implementing Classes:
    ContrastEnhancementImpl
    public interface ContrastEnhancement
    The ContrastEnhancement object defines contrast enhancement for a channel of a false-color image or for a color image.

    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)

    • Method Detail

      • getMethod

        ContrastMethod getMethod()
        We use a codeList to enable more enchancement type possibilities.

      • setMethod

        void setMethod​(ContrastMethod method)
        Used to set the contrast enhancement method used.

      • setGammaValue

        void setGammaValue​(Expression gamma)
        Parameters:
        gamma - How much to brighten (greater than 1) or dim (less than 1) this channel; use 1.0 to indicate no change.

      • 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

      • accept

        Object accept​(TraversingStyleVisitor visitor,
              Object extraData)
        calls the visit method of a StyleVisitor
        Parameters:
        visitor - the style visitor

      • getOptions

        Map<String,​Expression> getOptions()
        Return vendor options relating to the enhancement method
        Returns:
        a Map containing expressions with string keys.

      • hasOption

        boolean hasOption​(String key)
        check if vendor option key is available
        Parameters:
        key - - the name of the option to check
        Returns:
        true if present

      • addOption

        void addOption​(String key,
               Expression value)
        Store a vendor option
        Parameters:
        key - - the name of the option
        value - an expression that evaluates to it's value

      • accept

        void accept​(StyleVisitor visitor)
        Traversal of the style data structure.

      • setOptions

        void setOptions​(Map<String,​Expression> options)
        Parameters:
        options - a Map of VendorOptions

      • getOption

        Expression getOption​(String string)
        Returns:
        An expression for the matching VendorOption

      • setMethod

        void setMethod​(ContrastMethodStrategy method)
        Convenience method to allow users to pass in a ContrastEnhancementMethod to update Method and Options in one go.
        Parameters:
        method - the ContrastEnhancementMethod that underlies this enhancement