你好，麻烦提供出现问题的具体机型、微信版本号、系统版本号，以及能复现问题的代码片段（https://developers.weixin.qq.com/miniprogram/dev/devtools/minicode.html）

微信版本 8.0.48 ios17.4

<canvas

          class="handWriting"

          disable-scroll="true"

          @touchstart="uploadScaleStart"

          @touchmove="uploadScaleMove"

          @touchend="uploadScaleEnd"

          canvas-id="handWriting"

        >

                  </canvas

        >

 uploadScaleMove: function (e) {

      if (e.type != "touchmove") return false;

      if (e.cancelable) {

        if (!e.defaultPrevented) {

          e.preventDefault();

        }

      }

      let point = {

        x: e.touches[0].x,

        y: e.touches[0].y,

      }

      if (point.y < this.cutArea.top) {

        this.cutArea.top = point.y;

      }

      if (point.y < 0) this.cutArea.top = 0;

      if (point.x > this.cutArea.right) {

        this.cutArea.right = point.x;

      }

      if (this.canvasWidth - point.x <= 0) {

        this.cutArea.right = this.canvasWidth;

      }

      if (point.y > this.cutArea.bottom) {

        this.cutArea.bottom = point.y;

      }

      if (this.canvasHeight - point.y <= 0) {

        this.cutArea.bottom = this.canvasHeight;

      }

      if (point.x < this.cutArea.left) {

        this.cutArea.left = point.x;

      }

      if (point.x < 0) this.cutArea.left = 0;

      this.lastPoint = this.currentPoint;

      this.currentPoint = point;

      let currentLine = this.currentLine;

      currentLine.unshift({

        time: new Date().getTime(),

        dis: this.distance(this.currentPoint, this.lastPoint),

        x: point.x,

        y: point.y,

      });

      this.pointToLine(currentLine);

    },