canvas在 vue3 环境保存为图片到相册报错

这段代码在 vue2 中能够正常运行，也能保存为图片到相册，但是 vue3 环境报错：

"canvasToTempFilePath:fail Failed to execute 'drawImage' on 'CanvasRenderingContext2D': The provided value is not of type '(CSSImageValue or HTMLImageElement or SVGImageElement or HTMLVideoElement or HTMLCanvasElement or ImageBitmap or OffscreenCanvas or VideoFrame)'"

是在微信小程序模拟器中出现的

代码如下：

<template>  
    <view>  
        <canvas style="width: 300px; height: 400px;"  
            canvas-id="firstCanvas" id="firstCanvas"></canvas>  

        <button @click="saveImage11">保存</button>  
    </view>  

</template>  

<script>  
    export default {  
        data() {  
            return {  
                selectId: 'firstCanvas',  
                scrollLeft: 0,  
                canvas: null  
            }  
        },  
        props: ['content'],  
        watch: {  
            content(value) {  
                if (value) {  
                    this.createCanvas11()  
                }  
            }  
        },  
        methods: {  
            // 生成canvas  
            createCanvas11() {  
                const ctx = uni.createCanvasContext('firstCanvas', this);  
                ctx.clearRect(0, 0, 300, 400)  
                ctx.fillStyle = "#FFFFFF";  
                ctx.fillRect(0, 0, 300, 400);  

                function findBreakPoint(text, width, context) {  
                    var min = 0;  
                    var max = text.length - 1;  
                    while (min <= max) {  
                        var middle = Math.floor((min   max) / 2);  
                        var middleWidth = context.measureText(text.substr(0, middle)).width;  
                        var oneCharWiderThanMiddleWidth = context.measureText(text.substr(0, middle   1)).width;  
                        if (middleWidth <= width