d3.js - D3 缩放和鼠标悬停工具提示

Question

我在尝试使鼠标悬停在我的 D3 图形上时遇到问题(我不是 D3 专家)。我设法使线和点与缩放同步，但无法在点上方显示工具提示，不确定我是否遗漏了什么，如下图所示，一切正常。

你可以使用下面的按钮我的代码。谢谢您的帮助。

var data = JSON.parse('{"success":true,"response":[{"product_date":"2019-09-01","value":{"temperature":"30.6029968261719"}},{"product_date":"2019-09-02","value":{"temperature":"30.1170043945312"}},{"product_date":"2019-09-03","value":{"temperature":"30.0830078125"}},{"product_date":"2019-09-04","value":{"temperature":"30.2479858398438"}},{"product_date":"2019-09-05","value":{"temperature":"30.9110107421875"}},{"product_date":"2019-09-06","value":{"temperature":"31.3150024414062"}},{"product_date":"2019-09-07","value":{"temperature":"31.2909851074219"}},{"product_date":"2019-09-08","value":{"temperature":"30.7149963378906"}},{"product_date":"2019-09-09","value":{"temperature":"30.010009765625"}},{"product_date":"2019-09-10","value":{"temperature":"29.7990112304688"}},{"product_date":"2019-09-11","value":{"temperature":"29.6549987792969"}},{"product_date":"2019-09-12","value":{"temperature":"30.0769958496094"}},{"product_date":"2019-09-13","value":{"temperature":"30.0830078125"}},{"product_date":"2019-09-14","value":{"temperature":"29.8619995117188"}},{"product_date":"2019-09-15","value":{"temperature":"30.0029907226562"}},{"product_date":"2019-09-16","value":{"temperature":"30.1080017089844"}},{"product_date":"2019-09-17","value":{"temperature":"30.6979980469"}},{"product_date":"2019-09-18","value":{"temperature":"30.3139953613"}},{"product_date":"2019-09-19","value":{"temperature":"30.5180053710938"}},{"product_date":"2019-09-20","value":{"temperature":"30.3720092773"}},{"product_date":"2019-09-21","value":{"temperature":"29.8710021973"}},{"product_date":"2019-09-22","value":{"temperature":"29.7460021972656"}},{"product_date":"2019-09-23","value":{"temperature":"29.5769958496"}},{"product_date":"2019-09-24","value":{"temperature":"29.1159973145"}},{"product_date":"2019-09-25","value":{"temperature":"28.908996582"}}]}');

      var svg = d3.select("svg"),
          margin = {top: 20, right: 20, bottom: 110, left: 40},
          margin2 = {top: 430, right: 20, bottom: 30, left: 40},
          width = +svg.attr("width") - margin.left - margin.right,
          height = +svg.attr("height") - margin.top - margin.bottom,
          height2 = +svg.attr("height") - margin2.top - margin2.bottom;

      var parseDate = d3.timeParse("%b %Y");

      var x = d3.scaleTime().range([0, width]),
          x2 = d3.scaleTime().range([0, width]),
          y = d3.scaleLinear().range([height, 0]),
          y2 = d3.scaleLinear().range([height2, 0]);

      var xAxis = d3.axisBottom(x),
          xAxis2 = d3.axisBottom(x2),
          yAxis = d3.axisLeft(y);

      var brush = d3.brushX()
          .extent([[0, 0], [width, height2]])
          .on("brush end", brushed);

      var zoom = d3.zoom()
          .scaleExtent([1, Infinity])
          .translateExtent([[0, 0], [width, height]])
          .extent([[0, 0], [width, height]])
          .on("zoom", zoomed);

      var line1 = d3.line()
          .curve(d3.curveMonotoneX)
          .x(function(d) { return x(d.date) })
          .y(function(d) { return y(d.value) });

      var line2 = d3.line()
          .curve(d3.curveMonotoneX)
          .x(function(d) { return x2(d.date) })
          .y(function(d) { return y2(d.value) });

      svg.append("defs").append("clipPath")
          .attr("id", "clip")
        .append("rect")
          .attr("width", width)
          .attr("height", height);

      var focus = svg.append("g")
          .attr("class", "focus")
          .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

      var points = svg.append('g')
          .attr("clip-path", "url(#clip)")
          .attr("transform", "translate(" + margin.left + "," + margin.top + ")")

      var context = svg.append("g")
          .attr("class", "context")
          .attr("transform", "translate(" + margin2.left + "," + margin2.top + ")");

      var div = d3.select("body").append("div")	
          .attr("class", "tooltip")				
          .style("opacity", 0);

      

      let vdata = data.response;

      // format the data
      vdata.forEach((d) => {
          d.date = d3.timeParse("%Y-%m-%d")(d.product_date);
          d.value = +d.value.temperature;
      });

      x.domain(d3.extent(vdata, function(d) { return d.date; }));
      y.domain([0, d3.max(vdata, function(d) { return d.value; })]);
      x2.domain(x.domain());
      y2.domain(y.domain());

      focus.append("path")
          .datum(vdata)
          .attr("clip-path", "url(#clip)")
          .attr("class", "line")
          .attr("fill", "none")
          .attr("stroke", "steelblue")
          .attr("stroke-width", 1.5)
          .attr("d", line1);

      focus.append("g")
          .attr("class", "axis axis--x")
          .attr("transform", "translate(0," + height + ")")
          .call(xAxis);

      focus.append("g")
          .attr("class", "axis axis--y")
          .call(yAxis);

      points.selectAll(".dot")
          .data(vdata)
          .enter().append("circle")
          .attr("class", "dot")
          .attr("cx", function(d, i) { return x(d.date) })
          .attr("cy", function(d) { return y(d.value) })
          .attr("r", 3)
          .attr("pointer-events", "all")
          .on("mouseover", function(d) {
            div.transition()		
                .duration(200)		
                .style("opacity", .9);		
            div	.html(parseDate(d.date) + "<br/>"  + f(d.value))	
                .style("left", (d3.event.pageX) + "px")		
                .style("top", (d3.event.pageY - 28) + "px");
          })
          .on("mouseout", function(d) {
            div.transition()		
                .duration(500)		
                .style("opacity", 0);
          });
      
      points.append("g")
          .attr("class", "axis axis--y")
          .call(yAxis);

      context.append("path")
          .datum(vdata)
          .attr("class", "line")
          .attr("fill", "none")
          .attr("stroke", "steelblue")
          .attr("stroke-width", 1.5)
          .attr("d", line2);

      context.append("g")
          .attr("class", "axis axis--x")
          .attr("transform", "translate(0," + height2 + ")")
          .call(xAxis2);

      context.append("g")
          .attr("class", "brush")
          .call(brush)
          .call(brush.move, x.range());

      svg.append("rect")
          .attr("class", "zoom")
          .attr("width", width)
          .attr("height", height)
          .attr("transform", "translate(" + margin.left + "," + margin.top + ")")
          .call(zoom);

      function brushed() {
        if (d3.event.sourceEvent && d3.event.sourceEvent.type === "zoom") return; // ignore brush-by-zoom
        var s = d3.event.selection || x2.range();
        x.domain(s.map(x2.invert, x2));
        focus.select(".line").attr("d", d3.line()
                  .x(function(d) { return x(d.date) })
                  .y(function(d) { return y(d.value) })
                  .curve(d3.curveMonotoneX)
                );
        focus.select(".axis--x").call(xAxis);

        points.selectAll('circle')
                .attr("cx", function(d, i) { return x(d.date) })
                .attr("cy", function(d) { return y(d.value) });
        points.select(".axis--x").call(xAxis);

        svg.select(".zoom").call(zoom.transform, d3.zoomIdentity
            .scale(width / (s[1] - s[0]))
            .translate(-s[0], 0));
      }

      function zoomed() {
        if (d3.event.sourceEvent && d3.event.sourceEvent.type === "brush") return; // ignore zoom-by-brush
        var t = d3.event.transform;
        x.domain(t.rescaleX(x2).domain());
        focus.select(".line").attr("d", d3.line()
                  .x(function(d) { return x(d.date) })
                  .y(function(d) { return y(d.value) })
                  .curve(d3.curveMonotoneX)
                );

        points.selectAll('circle')
                .attr("cx", function(d, i) { return x(d.date) })
                .attr("cy", function(d) { return y(d.value) });
        points.select(".axis--x").call(xAxis);

        focus.select(".axis--x").call(xAxis);
        context.select(".brush").call(brush.move, x.range().map(t.invertX, t));
      }

      function type(d) {
        d.date = parseDate(d.date);
        d.value = +d.value;
        return d;
      }

.area {
      fill: steelblue;
      clip-path: url(#clip);
    }

    .zoom {
      cursor: move;
      fill: none;
      pointer-events: all;
    }

    .dot {
      fill: steelblue;
      stroke: #fff;
    }

    div.tooltip {	
      position: absolute;			
      text-align: left;			
      width: 70px;					
      height: 28px;					
      padding: 3px;				
      font: 11px sans-serif;		
      background: lightsteelblue;	
      border: 0px;		
      border-radius: 3px;			
      pointer-events: none;			
    }

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.13.0/d3.min.js"></script>
<svg width="960" height="500"></svg>

Answer 1

为了进行缩放交互，您在绘图区域上放置了一个不可见的矩形:

  svg.append("rect")
      .attr("class", "zoom")
      .attr("width", width)
      .attr("height", height)
      .attr("transform", "translate(" + margin.left + "," + margin.top + ")")
      .call(zoom);

在附加 g 后执行此操作保存绘图，因此矩形位于点上方。

指针事件在与点交互之前被这个矩形拦截。

您可以做的是将矩形附加到 g被选为 focus然后用 selection.lower() 降低它(这只是移动它，所以它是 g 的第一个 child ，它具有首先或在绘图下方绘制它的效果):

  focus.append("rect")
      .attr("class", "zoom")
      .attr("width", width)
      .attr("height", height)
      .lower();
      .call(zoom);

但是现在我们遇到了相反的问题(尽管它很轻微):绘图会拦截鼠标事件，这意味着如果鼠标悬停在绘图上就无法缩放，因此我们可以稍微修改一下:

  focus.append("rect")
      .attr("class", "zoom")
      .attr("width", width)
      .attr("height", height)
      .lower();

      focus.call(zoom);

但是，如 focus不是 g的精选保存点，当鼠标悬停在一个点上时，图形不会缩放(当鼠标悬停在线上时，它会缩放)。同样，由于轴是 g 的一部分在 focus 中选择, 当鼠标悬停在轴上时可以进行缩放。

这可能是一个问题，也许不是，但为了解决这个问题，我们可以稍微调整 DOM 结构以确保绘图区域中的所有内容(底部轴上方和垂直轴右侧)与缩放交互，但是没有其他的。

为此，我们将点添加为焦点的子级 g ，并在不同的 g 上调用轴(我为你添加了一个新的):

      var axes = svg.append("g")
         .attr("transform", "translate(" + margin.left + "," + margin.top + ")")

      var points = focus.append('g')  // no need to add a transform, focus already has one.
          .attr("clip-path", "url(#clip)")

当然，我们需要更新我们调用轴的所有位置以在新的 g 上调用它。 .我们总共得到:

var data = JSON.parse('{"success":true,"response":[{"product_date":"2019-09-01","value":{"temperature":"30.6029968261719"}},{"product_date":"2019-09-02","value":{"temperature":"30.1170043945312"}},{"product_date":"2019-09-03","value":{"temperature":"30.0830078125"}},{"product_date":"2019-09-04","value":{"temperature":"30.2479858398438"}},{"product_date":"2019-09-05","value":{"temperature":"30.9110107421875"}},{"product_date":"2019-09-06","value":{"temperature":"31.3150024414062"}},{"product_date":"2019-09-07","value":{"temperature":"31.2909851074219"}},{"product_date":"2019-09-08","value":{"temperature":"30.7149963378906"}},{"product_date":"2019-09-09","value":{"temperature":"30.010009765625"}},{"product_date":"2019-09-10","value":{"temperature":"29.7990112304688"}},{"product_date":"2019-09-11","value":{"temperature":"29.6549987792969"}},{"product_date":"2019-09-12","value":{"temperature":"30.0769958496094"}},{"product_date":"2019-09-13","value":{"temperature":"30.0830078125"}},{"product_date":"2019-09-14","value":{"temperature":"29.8619995117188"}},{"product_date":"2019-09-15","value":{"temperature":"30.0029907226562"}},{"product_date":"2019-09-16","value":{"temperature":"30.1080017089844"}},{"product_date":"2019-09-17","value":{"temperature":"30.6979980469"}},{"product_date":"2019-09-18","value":{"temperature":"30.3139953613"}},{"product_date":"2019-09-19","value":{"temperature":"30.5180053710938"}},{"product_date":"2019-09-20","value":{"temperature":"30.3720092773"}},{"product_date":"2019-09-21","value":{"temperature":"29.8710021973"}},{"product_date":"2019-09-22","value":{"temperature":"29.7460021972656"}},{"product_date":"2019-09-23","value":{"temperature":"29.5769958496"}},{"product_date":"2019-09-24","value":{"temperature":"29.1159973145"}},{"product_date":"2019-09-25","value":{"temperature":"28.908996582"}}]}');

      var svg = d3.select("svg"),
          margin = {top: 20, right: 20, bottom: 110, left: 40},
          margin2 = {top: 430, right: 20, bottom: 30, left: 40},
          width = +svg.attr("width") - margin.left - margin.right,
          height = +svg.attr("height") - margin.top - margin.bottom,
          height2 = +svg.attr("height") - margin2.top - margin2.bottom;

      var parseDate = d3.timeParse("%b %Y");

      var x = d3.scaleTime().range([0, width]),
          x2 = d3.scaleTime().range([0, width]),
          y = d3.scaleLinear().range([height, 0]),
          y2 = d3.scaleLinear().range([height2, 0]);

      var xAxis = d3.axisBottom(x),
          xAxis2 = d3.axisBottom(x2),
          yAxis = d3.axisLeft(y);

      var brush = d3.brushX()
          .extent([[0, 0], [width, height2]])
          .on("brush end", brushed);

      var zoom = d3.zoom()
          .scaleExtent([1, Infinity])
          .translateExtent([[0, 0], [width, height]])
          .extent([[0, 0], [width, height]])
          .on("zoom", zoomed);

      var line1 = d3.line()
          .curve(d3.curveMonotoneX)
          .x(function(d) { return x(d.date) })
          .y(function(d) { return y(d.value) });

      var line2 = d3.line()
          .curve(d3.curveMonotoneX)
          .x(function(d) { return x2(d.date) })
          .y(function(d) { return y2(d.value) });

      svg.append("defs").append("clipPath")
          .attr("id", "clip")
        .append("rect")
          .attr("width", width)
          .attr("height", height);

      var focus = svg.append("g")
          .attr("class", "focus")
          .attr("transform", "translate(" + margin.left + "," + margin.top + ")");
          
      var axes = svg.append("g")
         .attr("transform", "translate(" + margin.left + "," + margin.top + ")")

      var points = focus.append('g')
          .attr("clip-path", "url(#clip)")


      var context = svg.append("g")
          .attr("class", "context")
          .attr("transform", "translate(" + margin2.left + "," + margin2.top + ")");

      var div = d3.select("body").append("div")	
          .attr("class", "tooltip")				
          .style("opacity", 0);

      

      let vdata = data.response;

      // format the data
      vdata.forEach((d) => {
          d.date = d3.timeParse("%Y-%m-%d")(d.product_date);
          d.value = +d.value.temperature;
      });

      x.domain(d3.extent(vdata, function(d) { return d.date; }));
      y.domain([0, d3.max(vdata, function(d) { return d.value; })]);
      x2.domain(x.domain());
      y2.domain(y.domain());

      focus.append("path")
          .datum(vdata)
          .attr("clip-path", "url(#clip)")
          .attr("class", "line")
          .attr("fill", "none")
          .attr("stroke", "steelblue")
          .attr("stroke-width", 1.5)
          .attr("d", line1);

      axes.append("g")
          .attr("class", "axis axis--x")
          .attr("transform", "translate(0," + height + ")")
          .call(xAxis);

      axes.append("g")
          .attr("class", "axis axis--y")
          .call(yAxis);

      points.selectAll(".dot")
          .data(vdata)
          .enter().append("circle")
          .attr("class", "dot")
          .attr("cx", function(d, i) { return x(d.date) })
          .attr("cy", function(d) { return y(d.value) })
          .attr("r", 3)
          .attr("pointer-events", "all")
          .on("mouseover", function(d) {
            div.transition()		
                .duration(200)		
                .style("opacity", .9);		
            div	.html(parseDate(d.date) + "<br/>"  + (d.value))	
                .style("left", (d3.event.pageX) + "px")		
                .style("top", (d3.event.pageY - 28) + "px");
          })
          .on("mouseout", function(d) {
            div.transition()		
                .duration(500)		
                .style("opacity", 0);
          });
      
      points.append("g")
          .attr("class", "axis axis--y")
          .call(yAxis);

      context.append("path")
          .datum(vdata)
          .attr("class", "line")
          .attr("fill", "none")
          .attr("stroke", "steelblue")
          .attr("stroke-width", 1.5)
          .attr("d", line2);

      context.append("g")
          .attr("class", "axis axis--x")
          .attr("transform", "translate(0," + height2 + ")")
          .call(xAxis2);

      context.append("g")
          .attr("class", "brush")
          .call(brush)
          .call(brush.move, x.range());

      focus.append("rect")
          .attr("class", "zoom")
          .attr("width", width)
          .attr("height", height)
          .lower();
          
      focus.call(zoom);

      function brushed() {
        if (d3.event.sourceEvent && d3.event.sourceEvent.type === "zoom") return; // ignore brush-by-zoom
        var s = d3.event.selection || x2.range();
        x.domain(s.map(x2.invert, x2));
        focus.select(".line").attr("d", d3.line()
                  .x(function(d) { return x(d.date) })
                  .y(function(d) { return y(d.value) })
                  .curve(d3.curveMonotoneX)
                );
        axes.select(".axis--x").call(xAxis);

        points.selectAll('circle')
                .attr("cx", function(d, i) { return x(d.date) })
                .attr("cy", function(d) { return y(d.value) });
        points.select(".axis--x").call(xAxis);

        svg.select(".zoom").call(zoom.transform, d3.zoomIdentity
            .scale(width / (s[1] - s[0]))
            .translate(-s[0], 0));
      }

      function zoomed() {
        if (d3.event.sourceEvent && d3.event.sourceEvent.type === "brush") return; // ignore zoom-by-brush
        var t = d3.event.transform;
        x.domain(t.rescaleX(x2).domain());
        focus.select(".line").attr("d", d3.line()
                  .x(function(d) { return x(d.date) })
                  .y(function(d) { return y(d.value) })
                  .curve(d3.curveMonotoneX)
                );

        points.selectAll('circle')
                .attr("cx", function(d, i) { return x(d.date) })
                .attr("cy", function(d) { return y(d.value) });
        points.select(".axis--x").call(xAxis);

        axes.select(".axis--x").call(xAxis);
        context.select(".brush").call(brush.move, x.range().map(t.invertX, t));
      }

      function type(d) {
        d.date = parseDate(d.date);
        d.value = +d.value;
        return d;
      }

.area {
      fill: steelblue;
      clip-path: url(#clip);
    }

    .zoom {
      cursor: move;
      fill: none;
      pointer-events: all;
    }

    .dot {
      fill: steelblue;
      stroke: #fff;
    }

    div.tooltip {	
      position: absolute;			
      text-align: left;			
      width: 70px;					
      height: 28px;					
      padding: 3px;				
      font: 11px sans-serif;		
      background: lightsteelblue;	
      border: 0px;		
      border-radius: 3px;			
      pointer-events: none;			
    }

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.13.0/d3.min.js"></script>
<svg width="960" height="500"></svg>