Javascript 使用焦点内插时，D3图形线重叠+；上下文图示例

我用一些排序数据尝试了D3 focus+上下文图，但路径线本身重叠。如果我使用线性插值，它可以正常工作，但是当我尝试使用单调或基数插值平滑图形时，它会重叠。有什么线索吗

代码：

JSFiddle：

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与基插值配合得相当好——在基插值中，直线不会通过所有点。如果你检查你的小提琴，路径根本不会通过5。我想让它通过这个点，这样我以后就可以在这些点上提供悬停功能。

var margin = {top: 10, right: 10, bottom: 100, left: 40},
    margin2 = {top: 430, right: 10, bottom: 20, left: 40},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom,
    height2 = 500 - margin2.top - margin2.bottom;

var parseDate = function(d){return new Date(d);};

var x = d3.time.scale().range([0, width]),
    x2 = d3.time.scale().range([0, width]),
    y = d3.scale.linear().range([height, 0]),
    y2 = d3.scale.linear().range([height2, 0]);

var xAxis = d3.svg.axis().scale(x).orient("bottom"),
    xAxis2 = d3.svg.axis().scale(x2).orient("bottom"),
    yAxis = d3.svg.axis().scale(y).orient("left");

var brush = d3.svg.brush()
    .x(x2)
    .on("brush", brushed);

var area = d3.svg.area()
    .interpolate("monotone")
    .x(function(d) { return x(d.date); })
    .y0(height)
    .y1(function(d) { return y(d.price); });

var area2 = d3.svg.area()
    .interpolate("monotone")
    .x(function(d) { return x2(d.date); })
    .y0(height2)
    .y1(function(d) { return y2(d.price); });

var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom);

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

function check(data) {
  x.domain(d3.extent(data.map(function(d) { return d.date; })));
  y.domain([0, d3.max(data.map(function(d) { return d.price; }))]);
  x2.domain(x.domain());
  y2.domain(y.domain());

  focus.append("path")
      .datum(data)
      .attr("class", "area")
      .attr("d", area);

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

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

  context.append("path")
      .datum(data)
      .attr("class", "area")
      .attr("d", area2);

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

  context.append("g")
      .attr("class", "x brush")
      .call(brush)
    .selectAll("rect")
      .attr("y", -6)
      .attr("height", height2 + 7);
};

function brushed() {
  x.domain(brush.empty() ? x2.domain() : brush.extent());
  focus.select(".area").attr("d", area);
  focus.select(".x.axis").call(xAxis);
}

function type(d) {
  d.date = parseDate(d.time);
  d.price = +d.count;
  return d;
}
data = [ 
                {
                    "count": 1, 
                    "time": 1387152000000
                }, 
                {
                    "count": 1, 
                    "time": 1390780800000
                }, 
                {
                    "count": 5, 
                    "time": 1390867200000
                }, 
                {
                    "count": 2, 
                    "time": 1390953600000
                }, 
                {
                    "count": 1, 
                    "time": 1391040000000
                }];
check(data.map(function(r){return type(r);}));