Question

我正在研究d3.js库，我正在关注这个tutorial来放大图表。我集成了所有内容并且工作得很好。这是我的最终计划：

<!DOCTYPE html>
<meta charset="utf-8">
<title>Zoom + Pan</title>
<style>

body {
  position: relative;
  width: 960px;
}

svg {
  font: 10px sans-serif;
  shape-rendering: crispEdges;
}

rect {
  fill: #ddd;
}

.axis path,
.axis line {
  fill: none;
  stroke: #fff;
  shape-rendering: crispEdges;
}

.dot {

}

button {
  position: absolute;
  right: 30px;
  top: 30px;
}

</style>
<button>Reset</button>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
<script>

var margin = {top: 40, right: 50, bottom: 60, left: 70},
    width = 1060 - margin.left - margin.right,
    height = 700 - margin.top - margin.bottom;

var zoom = d3.behavior.zoom()
    .scaleExtent([1, 10])
    .on("zoom", zoomed);

var x = d3.scale.linear()
    .domain([-width / 2, width / 2])
    .range([0, width]);

var y = d3.scale.linear()
    .domain([-height / 2, height / 2])
    .range([height, 0]);

var color = d3.scale.category10();


var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom")
    .tickSize(-height);;

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left")
    .tickSize(-width);

var kmeans = 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 + ")")
    .call(zoom);

d3.tsv("test.tsv", function(error, data) {
  if (error) throw error;

  data.forEach(function(d) {
    d.y = +d.y;
    d.x = +d.x;
  });

  x.domain(d3.extent(data, function(d) { return d.x; })).nice();
  y.domain(d3.extent(data, function(d) { return d.y; })).nice();

  kmeans.append("rect")
    .attr("width", width)
    .attr("height", height)

  kmeans.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis)
      .append("text")
      .attr("class", "label")
      .attr("x", 500)
      .attr("y", 50)
      .style("text-anchor", "end")
      .text("1° Principal Component");

  kmeans.append("g")
      .attr("class", "y axis")
      .call(yAxis)
      .append("text")
      .attr("class", "label")
      .attr("transform", "rotate(-90)")
      .attr("x", -200)
      .attr("y", -50)
      .attr("dy", ".71em")
      .style("text-anchor", "end")
      .text("2° Principal Component");

  var dot = kmeans.selectAll(".dot")
      .data(data)
    .enter().append("circle")
      .attr("class", "dot")
      .attr("r", 3.5)
      .attr("cx", function(d) { return x(d.x); })
      .attr("cy", function(d) { return y(d.y); })
      .style("fill", function(d) { return color(d.cluster); });

  var legend = kmeans.selectAll(".legend")
      .data(color.domain())
    .enter().append("g")
      .attr("class", "legend")
      .attr("transform", function(d, i) { return "translate(-100," + i * 20 + ")"; });

  legend.append("rect")
      .attr("x", width - 18)
      .attr("width", 18)
      .attr("height", 18)
      .style("fill", color);

  legend.append("text")
      .attr("x", width - 24)
      .attr("y", 9)
      .attr("dy", ".35em")
      .style("text-anchor", "end")
      .text(function(d) { return d; });

});

d3.select("button").on("click", reset);

function zoomed() {
  kmeans.select(".x.axis").call(xAxis);
  kmeans.select(".y.axis").call(yAxis);
}

function reset() {
  d3.transition().duration(750).tween("zoom", function() {
    var ix = d3.interpolate(x.domain(), [-width / 2, width / 2]),
        iy = d3.interpolate(y.domain(), [-height / 2, height / 2]);
    return function(t) {
      zoom.x(x.domain(ix(t))).y(y.domain(iy(t)));
      zoomed();
    };
  });
}

</script>

这是test.tsv：

x   y   cluster
-1.0403321821456555 -0.9975352942962847 1 Cluster
-1.0404728255519613 -1.0021499065423058 1 Cluster
-1.0405312135780753 -1.0036348433263207 1 Cluster
-1.0405417259454817 -0.9883123582794969 1 Cluster
-1.0406344016908704 -0.9988259809896288 1 Cluster
-1.0406850822323188 -1.004030268612692  1 Cluster
-1.0406958447337742 -1.0065636473623911 1 Cluster
-1.0408667295862442 -1.0046081788513885 1 Cluster
-1.0408845367165218 -0.995137367062602  1 Cluster
-1.040932294864444  -0.991519347648691  1 Cluster
-1.040976952803462  -0.9833995692226501 1 Cluster
-1.0409896369345166 -0.9951495809699621 1 Cluster
-1.0410051379794218 -0.99448305469843   1 Cluster
-1.0410265061033306 -0.9951333768928067 1 Cluster
-1.0410330574179099 -0.9949308462686461 1 Cluster
-1.0410357249485886 -1.0053243527321372 1 Cluster
-1.0410491702402065 -1.006726904241483  1 Cluster
-1.041049812593761  -0.9865506278675225 1 Cluster

如果有人运行此代码，它会显示情节，但其中的元素仍然是不可分割的。有人能告诉我什么是错的吗？

Answer 1

在zoomed()功能中，您只更新两个轴。您没有更新图表中的svg元素（在您的案例中为svg-circle元素）。

如果您将以下内容添加到zoomed()功能中，则该功能应该有效：

kmeans.selectAll(".dot")
  .attr("cx", function(d) { return x(d.x); })
  .attr("cy", function(d) { return y(d.y); })

可能值得一提的是，这显然不会扩大您的圈子。这将只调整图表的域并相应地重新定位元素。如果您正在寻找真正的缩放效果，我建议您使用以下内容：

kmeans.attr("transform", "translate(" + d3.event.translate + ")scale(" + d3.event.scale + ")");

如何使用d3.js缩放图表内的元素

1 个答案: