javascript - d3 中的条形位置与轴不匹配

Question

我有一个使用 d3js 制作的条形图，但我无法沿 x 轴正确定位条形。条形图未相对于轴抽动定位。

以下是相同的片段。

var width = 216;
var height = 200;
var barPadding = 18;
var barWidth = 58;
var dataSize = d3.selectAll(dataset).size();
var margin = { top: 10, right: 0, bottom: 58, left: 30 };
var width_box_sizing_border_box = width + margin.left + margin.right;
var height_box_sizing_border_box = height + margin.bottom + margin.top;
//var start = (width - margin.left - margin.right - (dataSize * barWidth) + barPadding) / 2;

var graph;
var xScale;
var yScale;
var dataset;

var xTicks = 6;
var yTicks = 6;

dataset = [{ desc: 'test1', val: 40 }, { desc: 'some dummy text here', val: 120 }];

xScale = d3.scaleBand()
    .domain(dataset.map(function (d) {
        return d.desc;
    }))
    .range([margin.left, width-margin.right]);

yScale = d3.scaleLinear()
    .range([height, 0])
    .domain([0, 350]);

graph = d3.select("#graph")
    .append("svg")
    .attr("class", "bar-chart")
    .attr("width", width_box_sizing_border_box)
    .attr("height", height_box_sizing_border_box)

graph.append("g")
    .attr("class", "x-scale")
    .attr("transform", "translate(0," + (height + margin.top) + ")")
    .call(d3.axisBottom(xScale).ticks(xTicks))
    .selectAll(".tick text")
    .call(wrap, xScale.bandwidth());

graph.append("g")
    .attr("class", "y-scale")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")")
    .call(d3.axisLeft(yScale).ticks(yTicks).tickPadding(10));

graph
    .append("g")
    .attr("transform", "translate(0," + margin.top + ")")
    .attr('class', 'graph-placeholder')
    .selectAll("rect")
    .data(dataset)
    .enter()
    .append("rect")
    .attr("class", "bar1")
    .attr("height", height)
    .attr("width", barWidth - barPadding)
    .attr('x', d => xScale(d.desc));

graph
    .append("g")
    .attr("transform", "translate(0," + margin.top + ")")
    .attr('class', 'graph-main')
    .selectAll("bar1")
    .data(dataset)
    .enter()
    .append("rect")
    .attr("class", "bar2")
    .attr('x', d => xScale(d.desc))
    .attr("y", function (d) {
        return yScale(d.val);
    })
    .attr("height", function (d) {
        return height - yScale(d.val);
    })
    .attr("width", barWidth - barPadding);


graph
    .append("g")
    .attr("transform", "translate(0," + margin.top + ")")
    .attr('class', 'bar-label')
    .selectAll("text")
    .data(dataset)
    .enter()
    .append("text")
    .text(d => d.val + '%')
    .attr('x', d => xScale(d.desc))
    .attr("y", function (d) {
        return yScale(d.val) - 5;
    })

function wrap(text, width) {
    text.each(function () {
        var text = d3.select(this),
            words = text.text().split(/\s+/).reverse(),
            word,
            line = [],
            lineNumber = 0,
            lineHeight = 1,
            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);
            }
        }
    });
}

.bar-chart {
  background-color: #ccc;
}

.bar2 {
  fill: steelblue;
}

.bar1 {
  fill: #f2f2f2;
}

text {
  font-size: 12px;
  text-anchor: middle;
}

.bar-label text {
  text-anchor: start;
}
path.domain {
  stroke-width: 0;
  display: none;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
<div class="container">
  <div id="graph"></div>
</div>

Answer 1

这是计算中心点以放置条形图/文本的方法

栏和文本: xScale.bandwidth()/2 - barWidth/2

文本的额外偏移以使其在条形内居中: 分配文本属性后，根据 barWidth 和此特定文本宽度定位文本(即 x)。

简而言之:barWidth/2 - textWidth/2 为此，您可以使用 getBBox方法。方法如下:

.attr('x', function (d) {
    return xScale(d.desc) + ((barWidth - barPadding)/2 - d3.select(this).node().getBBox().width/2);
});

将上述 2 项更改应用到您的图表，这是您的 fiddle 的一个分支(和一个内联代码段)

var width = 216;
var height = 200;
var barPadding = 18;
var barWidth = 58;
var dataSize = d3.selectAll(dataset).size();
var margin = { top: 10, right: 0, bottom: 58, left: 30 };
var width_box_sizing_border_box = width + margin.left + margin.right;
var height_box_sizing_border_box = height + margin.bottom + margin.top;
//var start = (width - margin.left - margin.right - (dataSize * barWidth) + barPadding) / 2;

var graph;
var xScale;
var yScale;
var dataset;

var xTicks = 6;
var yTicks = 6;

dataset = [{ desc: 'test1', val: 40 }, { desc: 'some dummy text here', val: 120 }];

xScale = d3.scaleBand()
    .domain(dataset.map(function (d) {
        return d.desc;
    }))
    .range([margin.left, width-margin.right]);

yScale = d3.scaleLinear()
    .range([height, 0])
    .domain([0, 350]);

graph = d3.select("#graph")
    .append("svg")
    .attr("class", "bar-chart")
    .attr("width", width_box_sizing_border_box)
    .attr("height", height_box_sizing_border_box)

graph.append("g")
    .attr("class", "x-scale")
    .attr("transform", "translate(0," + (height + margin.top) + ")")
    .call(d3.axisBottom(xScale).ticks(xTicks))
    .selectAll(".tick text")
    .call(wrap, xScale.bandwidth());

graph.append("g")
    .attr("class", "y-scale")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")")
    .call(d3.axisLeft(yScale).ticks(yTicks).tickPadding(10));

graph
    .append("g")
    .attr("transform", "translate(" + (xScale.bandwidth()/2 - (barWidth - barPadding)/2) + "," + margin.top + ")")
    .attr('class', 'graph-placeholder')
    .selectAll("rect")
    .data(dataset)
    .enter()
    .append("rect")
    .attr("class", "bar1")
    .attr("height", height)
    .attr("width", barWidth - barPadding)
    .attr('x', d => xScale(d.desc));

graph
    .append("g")
    .attr("transform", "translate(" + (xScale.bandwidth()/2 - (barWidth - barPadding)/2) + "," + margin.top + ")")
    .attr('class', 'graph-main')
    .selectAll("bar1")
    .data(dataset)
    .enter()
    .append("rect")
    .attr("class", "bar2")
    .attr('x', d => xScale(d.desc))
    .attr("y", function (d) {
        return yScale(d.val);
    })
    .attr("height", function (d) {
        return height - yScale(d.val);
    })
    .attr("width", barWidth - barPadding);


graph
    .append("g")
    .attr("transform", "translate(" + (xScale.bandwidth()/2 - (barWidth - barPadding)/2) + "," + margin.top + ")")
    .attr('class', 'bar-label')
    .selectAll("text")
    .data(dataset)
    .enter()
    .append("text")
    .text(d => d.val + '%')
    .attr("y", function (d) {
        return yScale(d.val) - 5;
    }).attr('x', function (d) {
    	return xScale(d.desc) + ((barWidth - barPadding)/2 - d3.select(this).node().getBBox().width/2);
    });

function wrap(text, width) {
    text.each(function () {
        var text = d3.select(this),
            words = text.text().split(/\s+/).reverse(),
            word,
            line = [],
            lineNumber = 0,
            lineHeight = 1,
            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);
            }
        }
    });
}

.bar-chart {
  background-color: #ccc;
}

.bar2 {
  fill: steelblue;
}

.bar1 {
  fill: #f2f2f2;
}

text {
  font-size: 12px;
  text-anchor: middle;
}

.bar-label text {
  text-anchor: start;
}
path.domain {
  stroke-width: 0;
  display: none;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
<div class="container">
  <div id="graph"></div>
</div>

fiddle 链接:http://jsfiddle.net/xsuL8q4j/

希望这对您有所帮助。