NewTOAPIA.Drawing.span_image_filter_rgba_bilinear.generate C# (CSharp) Method

            public void generate(out RGBA_Bytes destPixel, int x, int y)
            {
                base.interpolator().begin(x + base.filter_dx_dbl(), y + base.filter_dy_dbl(), 1);

                int* fg = stackalloc int[4];

                byte* fg_ptr;

                IImage imageSource = base.source().DestImage;
                int maxx = (int)imageSource.Width() - 1;
                int maxy = (int)imageSource.Height() - 1;
                ISpanInterpolator spanInterpolator = base.interpolator();

                unchecked
                {
                    int x_hr;
                    int y_hr;

                    spanInterpolator.coordinates(out x_hr, out y_hr);

                    x_hr -= base.filter_dx_int();
                    y_hr -= base.filter_dy_int();

                    int x_lr = x_hr >> (int)image_subpixel_scale_e.image_subpixel_shift;
                    int y_lr = y_hr >> (int)image_subpixel_scale_e.image_subpixel_shift;

                    int weight;

                    fg[0] = fg[1] = fg[2] = fg[3] = (int)image_subpixel_scale_e.image_subpixel_scale * (int)image_subpixel_scale_e.image_subpixel_scale / 2;

                    x_hr &= (int)image_subpixel_scale_e.image_subpixel_mask;
                    y_hr &= (int)image_subpixel_scale_e.image_subpixel_mask;

                    fg_ptr = imageSource.GetPixelPointerY(y_lr) + (x_lr * 4);

                    weight = (int)(((int)image_subpixel_scale_e.image_subpixel_scale - x_hr) *
                             ((int)image_subpixel_scale_e.image_subpixel_scale - y_hr));
                    fg[0] += weight * fg_ptr[0];
                    fg[1] += weight * fg_ptr[1];
                    fg[2] += weight * fg_ptr[2];
                    fg[3] += weight * fg_ptr[3];

                    weight = (int)(x_hr * ((int)image_subpixel_scale_e.image_subpixel_scale - y_hr));
                    fg[0] += weight * fg_ptr[4];
                    fg[1] += weight * fg_ptr[5];
                    fg[2] += weight * fg_ptr[6];
                    fg[3] += weight * fg_ptr[7];

                    ++y_lr;
                    fg_ptr = imageSource.GetPixelPointerY(y_lr) + (x_lr * 4);

                    weight = (int)(((int)image_subpixel_scale_e.image_subpixel_scale - x_hr) * y_hr);
                    fg[0] += weight * fg_ptr[0];
                    fg[1] += weight * fg_ptr[1];
                    fg[2] += weight * fg_ptr[2];
                    fg[3] += weight * fg_ptr[3];

                    weight = (int)(x_hr * y_hr);
                    fg[0] += weight * fg_ptr[4];
                    fg[1] += weight * fg_ptr[5];
                    fg[2] += weight * fg_ptr[6];
                    fg[3] += weight * fg_ptr[7];

                    fg[0] >>= (int)image_subpixel_scale_e.image_subpixel_shift * 2;
                    fg[1] >>= (int)image_subpixel_scale_e.image_subpixel_shift * 2;
                    fg[2] >>= (int)image_subpixel_scale_e.image_subpixel_shift * 2;
                    fg[3] >>= (int)image_subpixel_scale_e.image_subpixel_shift * 2;

                    destPixel.m_R = (byte)fg[OrderR];
                    destPixel.m_G = (byte)fg[OrderG];
                    destPixel.m_B = (byte)fg[ImageBuffer.OrderB];
                    destPixel.m_A = (byte)fg[OrderA];
                }
            }
#endif