ColorMatrixUtility.as

/**
 * User: Ray Yee
 * Date: 14-3-6
 * All rights reserved.
 */
package
{
    import flash.filters.ColorMatrixFilter;

    public class ColorMatrixUtility
    {
        public function ColorMatrixUtility()
        {
        }

        /**
         * 色彩饱和度
         *
         * @param n (N取值为0到255)
         * @return
         *
         */
        public static function createSaturationFilter( n:Number ):ColorMatrixFilter
        {
            return new ColorMatrixFilter( [0.3086 * (1 - n) + n, 0.6094 * (1 - n), 0.0820 * (1 - n), 0, 0,
                0.3086 * (1 - n), 0.6094 * (1 - n) + n, 0.0820 * (1 - n), 0, 0,
                0.3086 * (1 - n), 0.6094 * (1 - n)    , 0.0820 * (1 - n) + n, 0, 0,
                0, 0, 0, 1, 0] );
        }

        /**
         * 对比度
         *
         * @param n (N取值为0到10)
         * @return
         *
         */
        public static function createContrastFilter( n:Number ):ColorMatrixFilter
        {
            return new ColorMatrixFilter( [n, 0, 0, 0, 128 * (1 - n),
                0, n, 0, 0, 128 * (1 - n),
                0, 0, n, 0, 128 * (1 - n),
                0, 0, 0, 1, 0] );
        }

        /**
         * 亮度(N取值为-255到255)
         *
         * @param n
         * @return
         *
         */
        public static function createBrightnessFilter( n:Number ):ColorMatrixFilter
        {
            return new ColorMatrixFilter( [1, 0, 0, 0, n,
                0, 1, 0, 0, n,
                0, 0, 1, 0, n,
                0, 0, 0, 1, 0] );
        }

        /**
         * 颜色反相
         *
         * @return
         *
         */
        public static function createInversionFilter():ColorMatrixFilter
        {
            return new ColorMatrixFilter( [-1, 0, 0, 0, 255,
                0, -1, 0, 0, 255,
                0, 0, -1, 0, 255,
                0, 0, 0, 1, 0] );
        }

        /**
         * 色相偏移
         * @return
         *
         */
        public static function createHueFilter( n:Number ):ColorMatrixFilter
        {
            const p1:Number = Math.cos( n * Math.PI / 180 );
            const p2:Number = Math.sin( n * Math.PI / 180 );
            const p4:Number = 0.213;
            const p5:Number = 0.715;
            const p6:Number = 0.072;
            return new ColorMatrixFilter( [p4 + p1 * (1 - p4) + p2 * (0 - p4), p5 + p1 * (0 - p5) + p2 * (0 - p5), p6 + p1 * (0 - p6) + p2 * (1 - p6), 0, 0,
                p4 + p1 * (0 - p4) + p2 * 0.143, p5 + p1 * (1 - p5) + p2 * 0.14, p6 + p1 * (0 - p6) + p2 * -0.283, 0, 0,
                p4 + p1 * (0 - p4) + p2 * (0 - (1 - p4)), p5 + p1 * (0 - p5) + p2 * p5, p6 + p1 * (1 - p6) + p2 * p6, 0, 0,
                0, 0, 0, 1, 0] );
        }

        /**
         * 阈值
         *
         * @param n(N取值为-255到255)
         * @return
         *
         */
        public static function createThresholdFilter( n:Number ):ColorMatrixFilter
        {
            return new ColorMatrixFilter( [0.3086 * 256, 0.6094 * 256, 0.0820 * 256, 0, -256 * n,
                0.3086 * 256, 0.6094 * 256, 0.0820 * 256, 0, -256 * n,
                0.3086 * 256, 0.6094 * 256, 0.0820 * 256, 0, -256 * n,
                0, 0, 0, 1, 0] );
        }
    }
}