多线图表 d3 工具提示

Question

我正在尝试向多折线图添加工具提示，但无法按照我想要的方式对其进行格式化。目前我在连接点获得工具提示文本，但我想在顶部的 rect 中获取所有点数据，如示例图像 我正在使用 d3 作为图表。这是关于 mousemove 的一段代码。

.on('mousemove', function (e) { // mouse moving over canvas
  const mouse = e.clientX;
  d3.select(".mouse-line-" + chart_sel)
    .attr("d", function () {
      var d = "M" + mouse + "," + height;
      d += " " + mouse + "," + 0;
      return d;
    });

  d3.selectAll(".mouse-per-line-" + chart_sel)
    .attr("transform", function (d, i) {
      var xDate = x.invert(mouse),
        bisect = d3.bisector(function (d) { return d.date; }).right;
      idx = bisect(d.values, xDate);
      d3.select(".mouse-line-" + chart_sel)
        .attr("d", function () {
          var data = "M " + x(d.values[idx].date) + "," + (height);
     data += "L " + x(d.values[idx].date) + "," + 0;
          return data;
        });
      var beginning = 0,
        end = lines[i].getTotalLength(),
        target = null;

      while (true) {
        target = Math.floor((beginning + end) / 2);
        pos = lines[i].getPointAtLength(target);
        if ((target === end || target === beginning) && pos.x !== mouse[0]) {
          break;
        }
        if (pos.x > mouse[0]) end = target;
        else if (pos.x < mouse[0]) beginning = target;
        else break; //position found
      }
      d3.select(this).select('text')
        .text(Math.round(y.invert(pos.y)))
        .style("text-anchor", "start")
      return "translate(" + x(d.values[idx].date) + "," + y(d.values[idx].value) + ")";

    });
 })

这是 codepen 中代码的链接。

这是工具提示的示例

提前致谢！

Answer 1

我发现你的笔有一些错误：

您不能在 D3.V6 中使用 d3.pointer(this)。相反，从 mousemove 回调参数中获取指针位置：

.on('mousemove', e => {
  const x = e.clientX; // instead of mouse[0]
  ...
}

你格式化的路径字符串有'M'（移动到）但没有'L'（行到）指令，应该是'M x,y L x,y':

var data = "M " + x(d.values[idx].date) + "," + (height);
data += "L " + x(d.values[idx].date) + "," + 0;