【报Bug】uni.canvasPutImageData在IOS上执行失败

测试canvasPutImageData方法时，在H5端正常，在IOS端失败，代码如下

<template>  
    <div>  
        <canvas style="width: 170px; height: 170px;" canvas-id="canvasId"></canvas>  
    </div>  
</template>  

<script>  
    export default {  
        data() {  
            return {  
            };  
        },  
        onReady() {  
            const imagedata = []  
            for (let i = 0; i < 170 * 170; i++) {  
                imagedata.push(255)  
                imagedata.push(0)  
                imagedata.push(0)  
                imagedata.push(255)  
            }  
            const data = new Uint8ClampedArray(imagedata)  
            uni.canvasPutImageData({  
                canvasId: "canvasId",  
                x: 0,  
                y: 0,  
                width: 170,  
                height: 170,  
                data: data,  
                success(res) {  
                    console.log(123)  
                }  
            })  
        }  
    }  
</script>  

错误信息

22:00:34.469 [ERROR] : appServiceSDKScriptError  
22:00:34.469 undefined is not an object (evaluating 'window["__global"]["btoa"]'); at wx.canvasPutImageData  
22:00:34.469 H8o@__uniappservice.html:1:328367  
22:00:34.469 h5B@__uniappservice.html:1:297559  
22:00:34.469 R5B@__uniappservice.html:1:297956  
22:00:34.469 __uniappservice.html:1:239265  
22:00:34.469 onReady  
22:00:34.469 callHook$1  
22:00:34.469 onReady  
22:00:34.469 onReady@[native code]  
22:00:34.469 __uniappservice.html:1:790548  
22:00:34.469 [native code]  
22:00:34.469 __uniappservice.html:1:775658  
22:00:34.469 __uniappservice.html:1:785686  
22:00:34.469 __uniappservice.html:1:340663  
22:00:34.469 __uniappservice.html:1:233200  
22:00:34.469 S5d@__uniappservice.html:1:99298  
22:00:34.469 O9@__uniappservice.html:1:96124  
22:00:34.469 __uniappservice.html:1:273  
22:00:34.469 __uniappservice.html:1:205288  
22:00:34.469 __uniappservice.html:1:410978