https://developers.weixin.qq.com/miniprogram/dev/devtools/minicode.html         wx.createSelectorQuery().select('#canvas')             .fields({                 node: true,                 size: true,             })             .exec((res) => {                 let canvas = res[0].node                 const width = res[0].width                 const height = res[0].height                 ctx = canvas.getContext('2d')                 const dpr = wx.getSystemInfoSync().pixelRatio                 canvas.width = width * dpr                 canvas.height = height * dpr                 ctx.scale(dpr, dpr)                 // ctx.globalAlpha(1);                 this.bigCircle(0,0);             }) -------         ctx.beginPath();         ctx.arc(x, y, 130, Math.PI, 2 * Math.PI);         ctx.lineWidth = 25;         ctx.strokeStyle="#E5E5E5";         ctx.stroke();         ctx.closePath();