对图片进行画圆裁剪 超过两个 ios 显示不出来 但是开发工具和安卓正常

* 如何复现？

const ctx = wx.createCanvasContext('myCanvas');

ctx.drawImage(that.data.back, 0, 0, that.data.windowWidth, that.data.contentHeight);

ctx.save()

ctx.beginPath()

ctx.arc(30, 30, 25, 0, 2 * Math.PI)

ctx.clip()

ctx.drawImage(that.data.image, 30-25, 30-25, 50, 50)

ctx.restore()

ctx.save()

ctx.beginPath()

ctx.arc(100, 30, 25, 0, 2 * Math.PI)

ctx.clip()

ctx.drawImage(that.data.image, 100 - 25, 30 - 25, 50, 50)

ctx.restore()

ctx.save()

ctx.beginPath()

ctx.arc(160, 30, 25, 0, 2 * Math.PI)

ctx.clip()

ctx.drawImage(that.data.image, 160 - 25, 30 - 25, 50, 50)

ctx.restore()

ctx.draw(true)