docs: @NonNull
      public IconicsDrawable shadowRes(
              @DimenRes int radiusRes,
              @DimenRes int dxRes,
              @DimenRes int dyRes,
              @ColorRes int colorResId) {
          return shadowPx(
                  mContext.getResources().getDimensionPixelSize(radiusRes),
                  mContext.getResources().getDimensionPixelSize(dxRes),
                  mContext.getResources().getDimensionPixelSize(dyRes),
                  ContextCompat.getColor(mContext, colorResId));
      }