iphone12 微信浏览器 wxCanvasToTempFilePath 生成图片白屏

测试机型：iphone12，ios版本14.2，微信版本7.0.20

问题：安卓canvas图片生成正常,IOS出现白屏

async creatPic(){  
    const ctx = uni.createCanvasContext('shareCanvas');  
    // 绘制背景  
    ctx.setFillStyle('#FFFFFF');  
    ctx.fillRect(0, 0, createRpx2px(600)*4,createRpx2px(857)*4);  

    ctx.setTextAlign('left');  
    ctx.setFillStyle('#333333');  
    ctx.font = '60px Arial';  
    ctx.setTextBaseline('middle');  
    ctx.fillText('测试测试测试测试测试测试测试', 100, 100);   
    ctx.draw();  
       setTimeout(()=>{  
            const wxCanvasToTempFilePath = uni.canvasToTempFilePath;  
        wxCanvasToTempFilePath({  
            x: 0,  
            y: 0,  
            width: createRpx2px(600)*4,  
            height: createRpx2px(857)*4,  
            destWidth: createRpx2px(600)*4,  
            destHeight: createRpx2px(857)*4,  
            canvasId: 'shareCanvas',  
            success: (res) => {  
                this.sharePic = res.tempFilePath;  
                uni.hideLoading();  
            },  
            fail: (res) => {  
                console.log(res);  
                uni.hideLoading();  
                uni.showToast({  
                    title: '生成图片失败',  
                    icon: 'none'  
                })  
            }  
        });  
    },500);  

},