uniapp开发微信，要把页面的一部分内容生成图片，保存到手机

<movable-area class="hnb" :style="{width:screenWidth+'px',height:screenWidth+'px'}" >  
                <image :src="path" class="pbg" :style="{width:screenWidth+'px',height:screenWidth+'px'}"  
                    mode="aspectFit" >  
                </image>  

                <movable-view :x="x" :y="y" direction="all" @change="onChange" class="mvv"  
                    :style="{width:screenWidth/3+'px',height:screenWidth/3+'px'}">  

                    <image :src="thtp" class="pbg2" :style="{width:screenWidth/3+'px',height:screenWidth/3+'px'}"  
                        mode="aspectFit" @click="choosepic(0)" >  
                    </image>  

                </movable-view>  

                <image :src="path1" class="pbg2"  
                    :style="{bottom:0+'px',right:0+'px',width:screenWidth/2+'px',height:screenWidth/2+'px'}"  
                    mode="aspectFit" ></image>  

</movable-area>

要把movable-area 包裹的内容保存成图片，请问怎么处理