视频播放列表更新，增加分享海报生成

utils/util.js

@@ -1,3 +1,39 @@
 export function isEmpty(val){
 	return val===null||val===undefined||val===''
+}
+
+import {
+	getCurrentInstance,
+} from 'vue';
+export async function getElRect(elClass, instance,option) {
+	instance = instance ? instance : getCurrentInstance();
+	const query = uni.createSelectorQuery().in(instance.proxy);
+	try{
+		const res= await getEle(query,elClass,option)
+		return res
+	}catch(e){
+		console.log(e);
+	}
+}
+async function getEle(query,elClass,option){
+	return new Promise((resolve, reject)=>{
+		query.select('.' + elClass).fields({
+			size: true,
+			...option
+		}, res => {
+			// 如果节点尚未生成，res值为null，循环调用执行
+			if (!res) {
+				return setTimeout(() => {
+					getEle(query,elClass,option);
+				}, 10);
+			}
+			resolve(res);
+		}).exec();
+	})
+	
+}
+
+export async function getSafeBottomHeight(className, height = 16) {
+	const bottomEle = await getElRect(className)
+	return bottomEle.height + height
 }