d3:工具提示放在页面底部而不是数据旁边

d3: Tooltip placed on bottom of page instead of next to data

我是 d3 的新手,我一直在关注 www.d3-graph-gallery.com . These tutorials have worked very well for me, however, when it comes to displaying tooltips when hovering over data, things are weird. This tutorial 中的教程,展示了如何在热图上执行此操作。如您所见,它将工具提示创建为 div,然后将鼠标监听器添加到数据中,使工具提示 div 出现在正确的位置。这在 d3-graph-gallery 网站上运行良好。

不幸的是,它既不能在我的本地浏览器上运行,也不能在 Jsfiddle 上运行: https://jsfiddle.net/vcfhnu4q/

<!DOCTYPE html>
<meta charset="utf-8">

<!-- Load d3.js -->
<script src="https://d3js.org/d3.v6.js"></script>

<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>

<script>

// set the dimensions and margins of the graph
const margin = {top: 30, right: 30, bottom: 30, left: 30},
  width = 450 - margin.left - margin.right,
  height = 450 - margin.top - margin.bottom;

// append the svg object to the body of the page
const svg = d3.select("#my_dataviz")
.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})`);

// Labels of row and columns
const myGroups = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J"]
const myVars = ["v1", "v2", "v3", "v4", "v5", "v6", "v7", "v8", "v9", "v10"]

// Build X scales and axis:
const x = d3.scaleBand()
  .range([ 0, width ])
  .domain(myGroups)
  .padding(0.01);
svg.append("g")
  .attr("transform", `translate(0, ${height})`)
  .call(d3.axisBottom(x))

// Build X scales and axis:
const y = d3.scaleBand()
  .range([ height, 0 ])
  .domain(myVars)
  .padding(0.01);
svg.append("g")
  .call(d3.axisLeft(y));

// Build color scale
const myColor = d3.scaleLinear()
  .range(["white", "#69b3a2"])
  .domain([1,100])

//Read the data
d3.csv("https://raw.githubusercontent.com/holtzy/D3-graph-gallery/master/DATA/heatmap_data.csv").then( function(data) {

  // create a tooltip
  const tooltip = d3.select("#my_dataviz")
    .append("div")
    .style("opacity", 0)
    .attr("class", "tooltip")
    .style("background-color", "white")
    .style("border", "solid")
    .style("border-width", "2px")
    .style("border-radius", "5px")
    .style("padding", "5px")

  // Three function that change the tooltip when user hover / move / leave a cell
  const mouseover = function(event,d) {
    tooltip.style("opacity", 1)
  }
  const mousemove = function(event,d) {
    tooltip
      .html("The exact value of<br>this cell is: " + d.value)
      .style("left", (event.x)/2 + "px")
      .style("top", (event.y)/2 + "px")
  }
  const mouseleave = function(d) {
    tooltip.style("opacity", 0)
  }

  // add the squares
  svg.selectAll()
    .data(data, function(d) {return d.group+':'+d.variable;})
    .enter()
    .append("rect")
      .attr("x", function(d) { return x(d.group) })
      .attr("y", function(d) { return y(d.variable) })
      .attr("width", x.bandwidth() )
      .attr("height", y.bandwidth() )
      .style("fill", function(d) { return myColor(d.value)} )
    .on("mouseover", mouseover)
    .on("mousemove", mousemove)
    .on("mouseleave", mouseleave)
})
</script>

如果你查看 jsfiddle,你会看到工具提示位于页面底部,而不是鼠标悬停在单元格上时鼠标旁边,这对我来说很有意义,怎么可能在 svg 之上绘制 div ?它们不是分开的容器吗?

如何让它工作?

您的工具提示需要具有 position 样式。试试这个:

  // create a tooltip
  const tooltip = d3.select("#my_dataviz")
    .append("div")
    .style("opacity", 0)
    .attr("class", "tooltip")
    .style("background-color", "white")
    .style("border", "solid")
    .style("border-width", "2px")
    .style("border-radius", "5px")
    .style("padding", "5px")
    .style("position", "absolute")

<!DOCTYPE html>
<meta charset="utf-8">

<!-- Load d3.js -->
<script src="https://d3js.org/d3.v6.js"></script>

<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>

<script>

// set the dimensions and margins of the graph
const margin = {top: 30, right: 30, bottom: 30, left: 30},
  width = 450 - margin.left - margin.right,
  height = 450 - margin.top - margin.bottom;

// append the svg object to the body of the page
const svg = d3.select("#my_dataviz")
.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})`);

// Labels of row and columns
const myGroups = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J"]
const myVars = ["v1", "v2", "v3", "v4", "v5", "v6", "v7", "v8", "v9", "v10"]

// Build X scales and axis:
const x = d3.scaleBand()
  .range([ 0, width ])
  .domain(myGroups)
  .padding(0.01);
svg.append("g")
  .attr("transform", `translate(0, ${height})`)
  .call(d3.axisBottom(x))

// Build X scales and axis:
const y = d3.scaleBand()
  .range([ height, 0 ])
  .domain(myVars)
  .padding(0.01);
svg.append("g")
  .call(d3.axisLeft(y));

// Build color scale
const myColor = d3.scaleLinear()
  .range(["white", "#69b3a2"])
  .domain([1,100])

//Read the data
d3.csv("https://raw.githubusercontent.com/holtzy/D3-graph-gallery/master/DATA/heatmap_data.csv").then( function(data) {

  // create a tooltip
  const tooltip = d3.select("#my_dataviz")
    .append("div")
    .style("opacity", 0)
    .attr("class", "tooltip")
    .style("background-color", "white")
    .style("border", "solid")
    .style("border-width", "2px")
    .style("border-radius", "5px")
    .style("padding", "5px")
    .style("position", "absolute")

  // Three function that change the tooltip when user hover / move / leave a cell
  const mouseover = function(event,d) {
    tooltip.style("opacity", 1)
  }
  const mousemove = function(event,d) {
    tooltip
      .html("The exact value of<br>this cell is: " + d.value)
      .style("left", (event.x)/2 + "px")
      .style("top", (event.y)/2 + "px")
  }
  const mouseleave = function(d) {
    tooltip.style("opacity", 0)
  }

  // add the squares
  svg.selectAll()
    .data(data, function(d) {return d.group+':'+d.variable;})
    .enter()
    .append("rect")
      .attr("x", function(d) { return x(d.group) })
      .attr("y", function(d) { return y(d.variable) })
      .attr("width", x.bandwidth() )
      .attr("height", y.bandwidth() )
      .style("fill", function(d) { return myColor(d.value)} )
    .on("mouseover", mouseover)
    .on("mousemove", mousemove)
    .on("mouseleave", mouseleave)
})
</script>

编辑: 未来的建议 - 使用 Firefox Developer Edition。它有非常好的 CSS 样式检查工具,例如: