var dataColorFunction = function(x, y)
        {
                var T=x / xMax;
                var L=LastBright/100;
                var C=0.0;

                LastBright=1-LastBright

                if(T>0.5) {
                        T=1-T;
                        C=0.15;
                }

                var R1=0.1+C;
                var R2=0.5;
                var R=R1+(R2-R1)*T*2;

                var G1=0.25;
                var G2=0.25;
                var G=G1+(G2-G1)*T;

                var B1=0.5;
                var B2=0.0;
                var B=B1+(B2-B1)*T*2;

                var r = R-L;
                var g = G-L;
                var b = B-L;
                return "rgb(" + Math.floor(r * 255) + ", " + Math.floor(g * 255) + ", " + Math.floor(b * 255) + ")";
        };