docs: public static int filterColor(int color, Filter filter) {
          if (filter == Filter.NONE) {
              return color;
          }
          int a = color >>> 24;
          int r = (color >> 16) & 0xFF;
          int g = (color >> 8) & 0xFF;
          int b = color & 0xFF;
          switch (filter) {
              case GRAYSCALE:
                  r = g = b = (int) (0.213f * r + 0.715f * g + 0.072f * b);
                  break;
              case GRAYSCALE_INVERT:
                  r = g = b = 255 - (int) (0.213f * r + 0.715f * g + 0.072f * b);
                  break;
              case INVERT:
                  r = 255 - r;
                  g = 255 - g;
                  b = 255 - b;
                  break;
          }
          return (a << 24) | (r << 16) | (g << 8) | b;
      }