在D3.js v4中用轴过渡包装长标签

Question

这是原始示例：https://bl.ocks.org/mbostock/7555321。

我在x轴上添加了过渡，并做了两个小提琴，以证明在过渡上将长标签包裹在轴上的事实在版本3中有效，但在D3的版本4中无效。

svg.append("g")
    .attr("class", "x axis")
    .attr("transform", "translate(0," + height + ")")
    .transition()
    .call(xAxis)
  .selectAll(".tick text")
//  .call(wrap, x.rangeBand()); (v3)
    .call(wrap, x.bandwidth());

https://jsfiddle.net/cfwbh0st/
https://jsfiddle.net/Ls5ux9gv/

我该如何处理？谢谢。

Answer 1

当我发现问题的根本原因时，我正在重写您的逻辑。通过调用.transition()，可以将对象从选择内容更改为过渡对象。但是过渡对象don't have a .html() method。您没有意识到这一点，因为您使用了.call()。但是，该操作在过渡完成之前 执行，因此，滴答声将被默认行为覆盖。我将在下面提出两个解决方案。第一个是您的代码的改编版，第二个是我正在处理的代码。希望它将为您提供更多的指导。

尽可能接近您的代码

var margin = {top: 80, right: 180, bottom: 80, left: 180},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var x = d3.scaleBand()
    .rangeRound([0, width])
    .paddingInner(.1)
    .paddingOuter(.3);

var y = d3.scaleLinear()
    .range([height, 0]);

var xAxis = d3.axisBottom()
    .scale(x);

var yAxis = d3.axisLeft()
    .scale(y)
    .ticks(8, "%");

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 + ")");

d3.tsv("https://gist.githubusercontent.com/mbostock/7555321/raw/1b17baa35f75336a8d9f4c8292b1d1ab850f3d86/data.tsv", type, function(error, data) {
  x.domain(data.map(function(d) { return d.name; }));
  y.domain([0, d3.max(data, function(d) { return d.value; })]);

  svg.append("text")
      .attr("class", "title")
      .attr("x", x(data[0].name))
      .attr("y", -26)
      .text("Why Are We Leaving Facebook?");

  svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .transition()
      .call(xAxis)
      .on("end", function() {
        d3.select(this)
            .selectAll(".tick text")
            .call(wrap, x.bandwidth())
      });

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

  svg.selectAll(".bar")
      .data(data)
    .enter().append("rect")
      .attr("class", "bar")
      .attr("x", function(d) { return x(d.name); })
      .attr("width", x.bandwidth())
      .attr("y", function(d) { return y(d.value); })
      .attr("height", function(d) { return height - y(d.value); });
});

function wrap(textElements, width) {
  textElements.each(function() {
    var text = d3.select(this),
        words = text.text().split(/\s+/).reverse(),
        word,
        line = [],
        lineNumber = 0,
        lineHeight = 1.1, // ems
        y = text.attr("y"),
        dy = parseFloat(text.attr("dy")),
        tspan = text.text(null).append("tspan").attr("x", 0).attr("y", y).attr("dy", dy + "em");
    while (word = words.pop()) {
      
      line.push(word);
      tspan.text(line.join(" "));
      if (tspan.node().getComputedTextLength() > width) {
        line.pop();
        tspan.text(line.join(" "));
        line = [word];
        tspan = text.append("tspan").attr("x", 0).attr("y", y).attr("dy", ++lineNumber * lineHeight + dy + "em").text(word);
      }
    }
  });
}

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

.bar {
  fill: steelblue;
}

.bar:hover {
  fill: brown;
}

.title {
  font: bold 14px "Helvetica Neue", Helvetica, Arial, sans-serif;
}

.axis {
  font: 10px sans-serif;
}

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

.x.axis path {
  display: none;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.13.0/d3.min.js"></script>

var margin = {
    top: 80,
    right: 180,
    bottom: 80,
    left: 180
  },
  width = 960 - margin.left - margin.right,
  height = 500 - margin.top - margin.bottom;

var x = d3.scaleBand()
  .rangeRound([0, width])
  .paddingInner(.1)
  .paddingOuter(.3);

var y = d3.scaleLinear()
  .range([height, 0]);

var xAxis = d3.axisBottom()
  .scale(x);

var yAxis = d3.axisLeft()
  .scale(y)
  .ticks(8, "%");

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 + ")");

d3.tsv("https://gist.githubusercontent.com/mbostock/7555321/raw/1b17baa35f75336a8d9f4c8292b1d1ab850f3d86/data.tsv", type, function(error, data) {
  x.domain(data.map(function(d) {
    return d.name;
  }));
  y.domain([0, d3.max(data, function(d) {
    return d.value;
  })]);

  svg.append("text")
    .attr("class", "title")
    .attr("x", x(data[0].name))
    .attr("y", -26)
    .text("Why Are We Leaving Facebook?");

  svg.append("g")
    .attr("class", "x axis")
    .attr("transform", "translate(0," + height + ")")
    .transition()
    .call(xAxis)
    .on("end", function() {
      d3.select(this).selectAll(".tick text")
        .call(wrap, x.bandwidth())
    });

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

  svg.selectAll(".bar")
    .data(data)
    .enter().append("rect")
    .attr("class", "bar")
    .attr("x", function(d) {
      return x(d.name);
    })
    .attr("width", x.bandwidth())
    .attr("y", function(d) {
      return y(d.value);
    })
    .attr("height", function(d) {
      return height - y(d.value);
    });
});

function wrap(textElements, width) {
  textElements.each(function() {
    d3.select(this).html(function(text) {
      var words = text.split(/\s+/),
        word,
        lines = [],
        currentLine = '',
        lineNumber = 0,
        lineHeight = 1.1
      while (word = words.shift()) {
        if (getTextWidth(currentLine + word, "10px sans-serif") < width) {
          // We're safe to add the word
          currentLine += word + ' ';
        } else {
          // If we add the word, we exceed the line length
          // Trim to remove the last space
          lines.push('<tspan x="0" y="9" dy="' + (++lineNumber * lineHeight) + 'em">' + currentLine.trim() + '</tspan>')
          currentLine = word + ' ';
        }
      }

      lines.push('<tspan x="0" y="9" dy="' + (++lineNumber * lineHeight) + 'em">' + currentLine.trim() + '</tspan>')
      return lines.join('');
    });
  });
}

/**
 * Measure the width of a text were it to be rendered using a given font.
 *
 * @param {string} text the text to be measured
 * @param {string} font a valid css font value
 *
 * @returns {number} the width of the rendered text in pixels.
 */
function getTextWidth(text, font) {
  const element = document.createElement("canvas");
  const context = element.getContext("2d");
  context.font = font;

  return context.measureText(text).width;
};

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

.bar {
  fill: steelblue;
}

.bar:hover {
  fill: brown;
}

.title {
  font: bold 14px "Helvetica Neue", Helvetica, Arial, sans-serif;
}

.axis {
  font: 10px sans-serif;
}

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

.x.axis path {
  display: none;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.13.0/d3.min.js"></script>