带有鼠标悬停工具提示的折线图在 d3.js 中不起作用

Question

我使用此 http://bl.ocks.org/d3noob/6eb506b129f585ce5c8a 代码示例创建了折线图。我已经成功地重新创建了它。

该代码是

<!DOCTYPE html>
<meta charset="utf-8">
<style> /* set the CSS */

body { font: 12px Arial;}

path { 
    stroke: steelblue;
    stroke-width: 2;
    fill: none;
}

.axis path,
.axis line {
    fill: none;
    stroke: grey;
    stroke-width: 1;
    shape-rendering: crispEdges;
}

</style>
<body>

<!-- load the d3.js library -->    
<script src="http://d3js.org/d3.v3.min.js"></script>

<script>

// Set the dimensions of the canvas / graph
var margin = {top: 30, right: 20, bottom: 30, left: 50},
    width = 600 - margin.left - margin.right,
    height = 270 - margin.top - margin.bottom;

// Parse the date / time
var parseDate = d3.time.format("%d-%b-%y").parse,
    formatDate = d3.time.format("%d-%b"),
    bisectDate = d3.bisector(function(d) { return d.date; }).left;

// Set the ranges
// var x = d3.time.scale().range([0, width]);
var x = d3.scale.ordinal().rangePoints([0, width]);
var y = d3.scale.linear().range([height, 0]);

// Define the axes
var xAxis = d3.svg.axis().scale(x)
    .orient("bottom").ticks(5);

var yAxis = d3.svg.axis().scale(y)
    .orient("left").ticks(5);

// Define the line
var valueline = d3.svg.line()
    .interpolate('basis')
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.close); });
    
// Adds the svg canvas
var svg = d3.select("body")
    .append("svg")
        .attr("width", width + margin.left + margin.right)
        .attr("height", height + margin.top + margin.bottom)
    .append("g")
        .attr("transform", 
              "translate(" + margin.left + "," + margin.top + ")");

var lineSvg = svg.append("g"); 

var focus = svg.append("g") 
    .style("display", "none");

// Get the data
var data = [
  {
    "date": "w1",
    "close": 629.32
  },
  {
    "date": "w2",
    "close": 124.31
  },
  {
    "date": "w3",
    "close": 333.68
  },
  {
    "date": "w4",
    "close": 236.23
  }
]
    // data.forEach(function(d) {
    //     // d.date = parseDate(d.date);
    //     d.date = +d.date;
    //     d.close = +d.close;
    // });

    // Scale the range of the data
    x.domain(data.map(function(d) { return d.date; }));
    y.domain([0, d3.max(data, function(d) { return d.close; })]);

    // Add the valueline path.
    lineSvg.append("path")
        .attr("class", "line")
        .attr("d", valueline(data));

    // Add the X Axis
    svg.append("g")
        .attr("class", "x axis")
        .attr("transform", "translate(0," + height + ")")
        .call(xAxis);

    // Add the Y Axis
    svg.append("g")
        .attr("class", "y axis")
        .call(yAxis);

   // append the x line
    focus.append("line")
        .attr("class", "x")
        .style("stroke", "blue")
        .style("stroke-dasharray", "3,3")
        .style("opacity", 0.5)
        .attr("y1", 0)
        .attr("y2", height);

    // append the y line
    focus.append("line")
        .attr("class", "y")
        .style("stroke", "blue")
        .style("stroke-dasharray", "3,3")
        .style("opacity", 0.5)
        .attr("x1", width)
        .attr("x2", width);

    // append the circle at the intersection
    focus.append("circle")
        .attr("class", "y")
        .style("fill", "none")
        .style("stroke", "blue")
        .attr("r", 4);

    // place the value at the intersection
    focus.append("text")
        .attr("class", "y1")
        .style("stroke", "white")
        .style("stroke-width", "3.5px")
        .style("opacity", 0.8)
        .attr("dx", 8)
        .attr("dy", "-.3em");
    focus.append("text")
        .attr("class", "y2")
        .attr("dx", 8)
        .attr("dy", "-.3em");

    // place the date at the intersection
    focus.append("text")
        .attr("class", "y3")
        .style("stroke", "white")
        .style("stroke-width", "3.5px")
        .style("opacity", 0.8)
        .attr("dx", 8)
        .attr("dy", "1em");
    focus.append("text")
        .attr("class", "y4")
        .attr("dx", 8)
        .attr("dy", "1em");
    
    // append the rectangle to capture mouse
    svg.append("rect")
        .attr("width", width)
        .attr("height", height)
        .style("fill", "none")
        .style("pointer-events", "all")
        .on("mouseover", function() { focus.style("display", null); })
        .on("mouseout", function() { focus.style("display", "none"); })
        .on("mousemove", mousemove);

    function mousemove() {
        var x0 = x.invert(d3.mouse(this)[0]),
            i = bisectDate(data, x0, 1),
            d0 = data[i - 1],
            d1 = data[i],
            d = x0 - d0.date > d1.date - x0 ? d1 : d0;

        focus.select("circle.y")
            .attr("transform",
                  "translate(" + x(d.date) + "," +
                                 y(d.close) + ")");

        focus.select("text.y1")
            .attr("transform",
                  "translate(" + x(d.date) + "," +
                                 y(d.close) + ")")
            .text(d.close);

        focus.select("text.y2")
            .attr("transform",
                  "translate(" + x(d.date) + "," +
                                 y(d.close) + ")")
            .text(d.close);

        focus.select("text.y3")
            .attr("transform",
                  "translate(" + x(d.date) + "," +
                                 y(d.close) + ")")
            .text(formatDate(d.date));

        focus.select("text.y4")
            .attr("transform",
                  "translate(" + x(d.date) + "," +
                                 y(d.close) + ")")
            .text(formatDate(d.date));

        focus.select(".x")
            .attr("transform",
                  "translate(" + x(d.date) + "," +
                                 y(d.close) + ")")
                       .attr("y2", height - y(d.close));

        focus.select(".y")
            .attr("transform",
                  "translate(" + width * -1 + "," +
                                 y(d.close) + ")")
                       .attr("x2", width + width);
    }
</script>
</body>

行显示正确，但我无法像上面的示例那样设置鼠标悬停工具提示。我正面临错误，例如未定义反转功能...

Answer 1

在您链接的图表中，他使用了 x 轴的时间刻度（具有反转功能）。您正在使用序数刻度（没有反转函数）。反转函数用于计算给定鼠标位置的 x 轴上的值。

时间刻度对于每个鼠标位置总是有一个对应的 x 值（因为它是连续的，所以无论你的鼠标在哪里，你都有那个位置的日期时间）而序数刻度则没有没有所有鼠标位置的对应 x 值，因为它是离散的，即当鼠标位于中间时 x 值是多少，例如 w1 和 w2？

因此您的解决方案是更改为时间刻度（在这种情况下，您必须将 w1,w2,w3 e.t.c. 转换为日期时间对象）。

或者，如果您想坚持使用序数比例，则必须删除反转功能。由于反转函数用于计算给定鼠标位置的 x 值，因此您必须自己创建此逻辑。可以在 Inversion with ordinal scale 中找到灵感。所以将 var x0 = x.invert(d3.mouse(this)[0]) 替换为

    var xPos = d3.mouse(this)[0];
    console.log("hovering at " + xPos);
    var leftEdges = x.range();
    var width = x.rangeBand();
    var j;
    for(j=0; xPos > (leftEdges[j] + width); j++) {}
        //do nothing, just increment j until case fails
    console.log("Clicked on " + x.domain()[j]);
    var x0 = x.domain()[j];

带有鼠标悬停工具提示的折线图在 d3.js 中不起作用

line chart with mouseover tooltip is not working in d3.js

javascript

d3.js

nvd3.js