设置 d3 图表的 y 轴以适合最宽的标签?

2022-01-25 00:00:00 label d3.js linechart javascript

我正在用 d3 绘制折线图，​​一切正常.但是，我必须在图表区域的左侧留出足够的边距，以适应我认为可能是最宽 y 轴文本标签的任何内容.我想根据最宽的标签调整每个图表的空间.

I'm drawing line charts with d3 and it all works fine. However, I have to leave enough margin on the left of the chart area to fit whatever I think might be the widest y-axis text label. I'd like to adjust this space for each chart, depending on the widest label.

最初我以为我可以找到最大 y 值，创建一个隐藏的文本对象，计算出它的宽度，然后在创建图表时将该值用作左边距.有点讨厌，但它给了我一个价值.

Initially I thought I could find the maximum y value, create a hidden text object, work out how wide that is, and use that value for the left margin when creating the chart. A bit nasty, but it gets me a value.

但是，如果最大 y 值是1598.538"，那么最顶部的 y 轴标签可能是1500"……也就是说，要窄得多.

However, if the maximum y value is, say "1598.538" the top-most y-axis label might be "1500"... ie, a lot narrower.

所以我想我想找到实际上是最顶层标签的宽度.但是如果不绘制图表和轴，测量宽度并再次真实绘制，我无法想到如何做到这一点.听起来很恶心！有没有一种不讨厌的方法来做到这一点?

So I guess I want to find the width of whatever will actually be the top-most label. But I can't think how to do that without drawing the chart and axis, measuring that width, and drawing it again for real. Which sounds nasty! Is there a non-nasty way to do this?

更新

这是我的代码的一部分，使用了 Lars 的建议，只是为了显示它适合的位置:

Here's part of my code, using Lars' suggestion, just to show where it fits in:

// I did have
// `.attr("transform", "translate(" + margin.left + "," + margin.top ")")`
// on the end of this line, but I've now moved that to the bottom.
var g = svg.select("g");

// Add line paths.
g.selectAll(".line").data(data)
    .enter()
    .append("path")
    .attr("d", line);

// Update the previously-created axes.
g.select(".axis-x")
    .attr("transform", "translate(0," + yScale.range()[0] + ")"))
    .call(xAxis);
g.select(".axis-y")
    .call(yAxis);

// Lars's suggestion for finding the maximum width of a y-axis label:
var maxw = 0;
d3.select(this).select('.axis-y').selectAll('text').each(function(){
  if (this.getBBox().width > maxw) maxw = this.getBBox().width;
});

// Now update inner dimensions of the chart.
g.attr("transform", "translate(" + (maxw + margin.left) + "," + margin.top + ")");

推荐答案

您可以将所有内容放在 g 元素中，并根据最大宽度设置 transform.类似于

You can put everything inside a g element and set transform based on the max width. Something along the lines of

var maxw = 0;
yAxisContainer.selectAll("text").each(function() {
    if(this.getBBox().width > maxw) maxw = this.getBBox().width;
});
graphContainer.attr("transform", "translate(" + maxw + ",0)");

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