flutter 高斯实现模糊

flutter的高斯模糊其实是一个模糊化处理的Container元素块 定位在图片的上层

 ClipRRect( //切割很重要
            child: Stack(
              overflow: Overflow.clip,
              alignment: Alignment.center,
              children: <Widget>[
                Container(

                  width:double.infinity,
                  child:Container(//用那好种图片组件随便
                     width:double.infinity,

                    height:ScreenUtil.instance.setHeight(200),
                      decoration:BoxDecoration(
                        color:Color.fromRGBO(124, 127,115, .3),
                        borderRadius: BorderRadius.circular(20),
                        image:DecorationImage(
                          image: NetworkImage("${图片链接 ?? ''}"),
                          fit: BoxFit.cover,

                        )
                      ),

                    ),
                ),
                Positioned.fill(
                  child: BackdropFilter(
                    filter:ImageFilter.blur(sigmaX:3, sigmaY:3),//可以看源码
                    child:Container(
                      decoration:BoxDecoration(
                        color:(Color.fromRGBO(225, 225,225, 1)).withOpacity(0.06),
                        borderRadius: BorderRadius.circular(20),
                      ),

                    ),
                  ),
                )
              ],