/*
     跳过java层直接从C/C++层返回Bitmap，节省了在java层的内存.
    相比较BitmapFactory.decodeResource方法，更高效

    @param resId
     @return
    */
    private Bitmap createBitmapFormNative(int resId)
    {
    Options options = new Options();
    options.inPreferredConfig = Bitmap.Config.RGB_565;
    options.inPurgeable = true;
    options.inInputShareable = true;
    InputStream is = mContext.getResources().openRawResource(resId);
    return BitmapFactory.decodeStream(is, null, options);
    }