konva/src/filters/Sepia.js

(function() {
    /**
     * Sepia Filter
     * Based on: Pixastic Lib - Sepia filter - v0.1.0
     * Copyright (c) 2008 Jacob Seidelin, jseidelin@nihilogic.dk, http://blog.nihilogic.dk/
     * @function
     * @memberof Kinetic.Filters
     * @param {Object} imageData
     * @author Jacob Seidelin <jseidelin@nihilogic.dk>
     * @license MPL v1.1 [http://www.pixastic.com/lib/license.txt]
     */
     
    var Sepia = function (src, dst, opt) {
        var data = src.data,
            w = src.width,
            y = src.height,
            dstData = dst.data,
            w4 = w*4,
            offsetY,
            x,
            offset,
            or,
            og,
            ob,
            r,
            g,
            b;
        
        do {
            offsetY = (y-1)*w4;
            x = w;
            do {
                offset = offsetY + (x-1)*4;
                
                or = data[offset];
                og = data[offset+1];
                ob = data[offset+2];

                r = or * 0.393 + og * 0.769 + ob * 0.189;
                g = or * 0.349 + og * 0.686 + ob * 0.168;
                b = or * 0.272 + og * 0.534 + ob * 0.131;

                dstData[offset] = r > 255 ? 255 : r;
                dstData[offset+1] = g > 255 ? 255 : g;
                dstData[offset+2] = b > 255 ? 255 : b;
                dstData[offset+3] = data[offset+3];
            } while (--x);
        } while (--y);
    };

  Kinetic.Filters.Sepia = function(src,dst,opt){
    if( this === Kinetic.Filters ){
      Sepia(src, dst||src, opt );
    }else{
      Sepia.call(this, src, dst||src, {} );
    }
  };

})();