Pinta.ImageManipulation.ColorBgra.BlendColors4W16IP C# (CSharp) Method

        public static ColorBgra BlendColors4W16IP(ColorBgra c1, uint w1, ColorBgra c2, uint w2, ColorBgra c3, uint w3, ColorBgra c4, uint w4)
        {
#if DEBUG
            if ((w1 + w2 + w3 + w4) != 65536)
            {
                throw new ArgumentOutOfRangeException("w1 + w2 + w3 + w4 must equal 65536!");
            }
#endif

            const uint ww = 32768;
            uint af = (c1.A * w1) + (c2.A * w2) + (c3.A * w3) + (c4.A * w4);
            uint a = (af + ww) >> 16;

            uint b;
            uint g;
            uint r;

            if (a == 0)
            {
                b = 0;
                g = 0;
                r = 0;
            }
            else
            {
                b = (uint)((((long)c1.A * c1.B * w1) + ((long)c2.A * c2.B * w2) + ((long)c3.A * c3.B * w3) + ((long)c4.A * c4.B * w4)) / af);
                g = (uint)((((long)c1.A * c1.G * w1) + ((long)c2.A * c2.G * w2) + ((long)c3.A * c3.G * w3) + ((long)c4.A * c4.G * w4)) / af);
                r = (uint)((((long)c1.A * c1.R * w1) + ((long)c2.A * c2.R * w2) + ((long)c3.A * c3.R * w3) + ((long)c4.A * c4.R * w4)) / af);
            }

            return ColorBgra.FromBgra((byte)b, (byte)g, (byte)r, (byte)a);
        }

        public static unsafe ColorBgra GetBilinearSampleWrapped(ISurface src, ColorBgra *srcDataPtr, int srcWidth, int srcHeight, float x, float y)
        {
            if (!Utility.IsNumber(x) || !Utility.IsNumber(y))
            {
                return(ColorBgra.Transparent);
            }

            float u = x;
            float v = y;

            unchecked {
                int  iu        = (int)Math.Floor(u);
                uint sxfrac    = (uint)(256 * (u - (float)iu));
                uint sxfracinv = 256 - sxfrac;

                int  iv        = (int)Math.Floor(v);
                uint syfrac    = (uint)(256 * (v - (float)iv));
                uint syfracinv = 256 - syfrac;

                uint wul = (uint)(sxfracinv * syfracinv);
                uint wur = (uint)(sxfrac * syfracinv);
                uint wll = (uint)(sxfracinv * syfrac);
                uint wlr = (uint)(sxfrac * syfrac);

                int sx = iu;
                if (sx < 0)
                {
                    sx = (srcWidth - 1) + ((sx + 1) % srcWidth);
                }
                else if (sx > (srcWidth - 1))
                {
                    sx = sx % srcWidth;
                }

                int sy = iv;
                if (sy < 0)
                {
                    sy = (srcHeight - 1) + ((sy + 1) % srcHeight);
                }
                else if (sy > (srcHeight - 1))
                {
                    sy = sy % srcHeight;
                }

                int sleft = sx;
                int sright;

                if (sleft == (srcWidth - 1))
                {
                    sright = 0;
                }
                else
                {
                    sright = sleft + 1;
                }

                int stop = sy;
                int sbottom;

                if (stop == (srcHeight - 1))
                {
                    sbottom = 0;
                }
                else
                {
                    sbottom = stop + 1;
                }

                ColorBgra cul = src.GetPoint(sleft, stop);
                ColorBgra cur = src.GetPoint(sright, stop);
                ColorBgra cll = src.GetPoint(sleft, sbottom);
                ColorBgra clr = src.GetPoint(sright, sbottom);

                ColorBgra c = ColorBgra.BlendColors4W16IP(cul, wul, cur, wur, cll, wll, clr, wlr);

                return(c);
            }
        }