Groovy source for rgb to hsv conversion since groovy doesn't have a properly working modulo operator.

rgbtohsv.groovy

def rgbToHSV(red, green, blue) {
    float r = red / 255f
    float g = green / 255f
    float b = blue / 255f
    float max = [r, g, b].max()
    float min = [r, g, b].min()
    float delta = max - min
    def hue = 0
    def saturation = 0
    if (max == min) {
        hue = 0
    } else if (max == r) {
        def h1 = (g - b) / delta / 6
        def h2 = h1.asType(int)
        if (h1 < 0) {
            hue = (360 * (1 + h1 - h2)).round()
        } else {
            hue = (360 * (h1 - h2)).round()
        }
        log.trace("rgbToHSV: red max=${max} min=${min} delta=${delta} h1=${h1} h2=${h2} hue=${hue}")
    } else if (max == g) {
        hue = 60 * ((b - r) / delta + 2)
        log.trace("rgbToHSV: green hue=${hue}")
    } else {
        hue = 60 * ((r - g) / (max - min) + 4)
        log.trace("rgbToHSV: blue hue=${hue}")
    }
    
    if (max == 0) {
        saturation = 0
    } else {
        saturation = delta / max * 100
    }
    
    def value = max * 100
    
    return [
        "red": red.asType(int),
        "green": green.asType(int),
        "blue": blue.asType(int),
        "hue": hue.asType(int),
        "saturation": saturation.asType(int),
        "value": value.asType(int),
    ]
}