通过canvas作图片缓存

通过canvas作图片缓存

测试环境在uniapp中

<template>
    <view class="content">
        <image class="logo" src="/static/logo.png"></image>
        <view class="text-area">
            <text class="title">{{title}}</text>
            <view class="">
                <image :src="imgSrc" mode=""></image>
            </view>
        </view>
    </view>
</template>
<script>
    export default {
        data() {
            return {
                title: 'Hello',
                imgSrc: '/static/logo.png'
            }
        },
        onLoad() {
            var that = this;
            that.loadPic();
        },
        methods: {
            loadPic(){
                var that = this;
                var url = "https://n.sinaimg.cn/spider20210721/200/w640h360/20210721/e9be-15a5a455644ce32c9bbfc8103a65ae39.jpg";
                uni.getImageInfo({  
                    src: url,  
                    success(res) {  
                        let img = new Image(); 
                        img.setAttribute("crossOrigin",'Anonymous')
                        img.src = res.path;  
                        console.log(img)  
                        let canvas = document.createElement('canvas');  
                        var ctx = canvas.getContext("2d");
                        img.onload = function(e){
                            var path = img;
                            ctx.drawImage(path, 0, 0)
                            var baseStr = canvas.toDataURL("image/jpeg", 1);
                            that.imgSrc = baseStr;
                        }
                    }  
                });  
            }
        }
    }
</script>
<style>
    .content {
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
    }
    .logo {
        height: 200rpx;
        width: 200rpx;
        margin-top: 200rpx;
        margin-left: auto;
        margin-right: auto;
        margin-bottom: 50rpx;
    }
    .text-area {
        display: flex;
        justify-content: center;
    }
    .title {
        font-size: 36rpx;
        color: #8f8f94;
    }
</style>