sets the user exponent to a given value . the exponent must be positive . if not , an illegalargumentexception will be thrown . the output image pixels will be placed through a transformation of the form : sample = integer_sample / 2 ^ bitdepth - 1.0 decoding_exponent = user_exponent / gamma_from_file display_exponent output = sample ^ decoding_exponent where gamma_from_file is the gamma of the file data , as determined by the gama , srgb , and/or iccp chunks , and display_exponent is the exponent of the intrinsic transfer curve of the display , generally 2.2 . input files which do not specify any gamma are assumed to have a gamma of 1/2 .2 ; such images may be displayed on a crt with an exponent of 2.2 using the default user exponent of 1.0 . the user exponent may be used in order to change the effective gamma of a file . if a file has a stored gamma of x , but the decoder believes that the true file gamma is y , setting a user exponent of y/x will produce the same result as changing the file gamma . this parameter affects the decoding of all image types . concode_field_sep boolean suppressAlpha concode_elem_sep boolean expandPalette concode_elem_sep boolean performGammaCorrection concode_elem_sep PNGEncodeParam encodeParam concode_elem_sep boolean expandGrayAlpha concode_elem_sep boolean generateEncodeParam concode_elem_sep boolean output8BitGray concode_elem_sep float userExponent concode_elem_sep float displayExponent concode_field_sep void setDisplayExponent concode_elem_sep void setPerformGammaCorrection concode_elem_sep void setEncodeParam concode_elem_sep void setExpandGrayAlpha concode_elem_sep float getUserExponent concode_elem_sep float getDisplayExponent concode_elem_sep boolean getSuppressAlpha concode_elem_sep boolean getPerformGammaCorrection concode_elem_sep void setOutput8BitGray concode_elem_sep void setSuppressAlpha concode_elem_sep boolean getExpandGrayAlpha concode_elem_sep void setGenerateEncodeParam concode_elem_sep PNGEncodeParam getEncodeParam concode_elem_sep void setExpandPalette concode_elem_sep boolean getExpandPalette concode_elem_sep boolean getOutput8BitGray concode_elem_sep boolean getGenerateEncodeParam
void function ( float arg0 ) { if ( arg0 <= 0.0F ) { throw new IllegalArgumentException ( PropertyUtil . getString ( "srini_string" ) ) ; } this . userExponent = arg0 ; }