D3.js:根据值更改条形的颜色

Question

我一直在试验d3.js条形图,我想根据y轴的值改变颜色,我该如何实现.我尝试添加线性渐变,但后来我失去了对它的控制.

我正在处理的代码基于:http://bost.ocks.org/mike/bar/

Answer 1

添加以下属性以适应颜色:

var data = [4, 8, 15, 16, 23, 42];

var width = 420,
  barHeight = 20;

var x = d3.scale.linear()
  .domain([0, d3.max(data)])
  .range([0, width]);

var chart = d3.select(".chart")
  .attr("width", width)
  .attr("height", barHeight * data.length);

var bar = chart.selectAll("g")
  .data(data)
  .enter().append("g")
  .attr("transform", function(d, i) {
    return "translate(0," + i * barHeight + ")";
  });

bar.append("rect")
  .attr("width", x)
  // add this attribute to change the color of the rect
  .attr("fill", function(d) {
    if (d > 25) {
      return "red";
    } else if (d > 10) {
      return "orange";
    }
    return "yellow";
  })
  .attr("height", barHeight - 1);

bar.append("text")
  .attr("x", function(d) {
    return x(d) - 3;
  })
  .attr("y", barHeight / 2)
  .attr("dy", ".35em")
  // add this attribute to change the color of the text
  .attr("fill", function(d) {
    if (d > 10) {
      return "white";
    }
    return "black";
  })
  .text(function(d) {
    return d;
  });

.chart text {
  font: 10px sans-serif;
  text-anchor: end;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>

<svg class="chart"></svg>