Class Contrast


  • public class Contrast
    extends LookupTableOperation
    Adjusts the contrast of an image. The amount of adjustment is given to the constructor as a percentage value between -100 and 100. -100 will make the resulting image middle-gray, 0 will leave it unchanged, 100 will map it to the eight corners of the color cube.

    Usage examples

    Both examples increase contrast by 30 percent.

    If all you want is to create a new image with adjusted contrast from the image data of an existing image, simply use the static helper method:

    PixelImage adjustedImage = Contrast.adjust(inputImage, 30);
    This leaves the original image inputImage unchanged and allocates a second image object which is here assigned to the variable adjustedImage.

    If you want more control over parameters, create your own Contrast object. You can then reuse image objects, e.g. to write the adjusted image data to the original image object:

     Contrast op = new Contrast();
     op.setInputImage(image);
     op.setOutputImage(image);
     op.setContrast(30);
     op.process();
     // at this point, image will contain the adjusted image data,
     // the original data wil be overwritten 
     
    Author:
    Marco Schmidt
    • Field Detail

      • contrast

        private int contrast
    • Constructor Detail

      • Contrast

        public Contrast()
    • Method Detail

      • adjust

        public static PixelImage adjust​(PixelImage input,
                                        int percentage)
        This static helper method is more simple to use when all you need are the standard options.
        Parameters:
        input - the image to work on
        percentage - contrast modification, from -100 to 100
        Returns:
        a new image with adjusted contrast
      • createLookupTable

        private int[] createLookupTable​(int numSamples,
                                        int contrast)
      • getContrast

        public int getContrast()
        Returns the contrast adjustment value associated with this opperation. The value lies between -100 and 100 (including both values).
        Returns:
        contrast adjustment
        See Also:
        setContrast(int)
      • setContrast

        public void setContrast​(int newContrast)
        Sets the value for contrast adjustment to be used within this operation.
        Parameters:
        newContrast - new contrast, between -100 and 100 (including both values)
        Throws:
        IllegalArgumentException - if the new contrast value is not in the above mentioned interval
        See Also:
        getContrast()