Question

我正在使用以下链接中找到的代码：

https://www.d3-graph-gallery.com/graph/heatmap_tooltip.html

如果下载此代码然后在浏览器中查看，您将注意到鼠标悬停时工具提示的位置不再相对于热图中的单元，而是朝着底部的长矩形显示。在将此代码与自己的代码集成之后，我注意到了同样的情况。

我必须添加什么以强制工具提示出现在相对于热图单元的位置上？任何帮助将不胜感激。

Answer 1

您可能会从该页面下载红色（“编辑我” ）左侧的框（即HTML）和其下方的框（即JavaScript）。如果单击下载代码按钮，也会发生同样的情况，下载的文件仅包含HTML和JavaScript。

那么，这就是你得到的：

// set the dimensions and margins of the graph
var 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
var 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
var myGroups = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J"]
var myVars = ["v1", "v2", "v3", "v4", "v5", "v6", "v7", "v8", "v9", "v10"]

// Build X scales and axis:
var 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:
var y = d3.scaleBand()
  .range([ height, 0 ])
  .domain(myVars)
  .padding(0.01);
svg.append("g")
  .call(d3.axisLeft(y));

// Build color scale
var 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", function(data) {

  // create a tooltip
  var 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
  var mouseover = function(d) {
    tooltip.style("opacity", 1)
  }
  var mousemove = function(d) {
    tooltip
      .html("The exact value of<br>this cell is: " + d.value)
      .style("left", (d3.mouse(this)[0]+70) + "px")
      .style("top", (d3.mouse(this)[1]) + "px")
  }
  var 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)
})

<!DOCTYPE html>
<meta charset="utf-8">

<!-- Load d3.js -->
<script src="https://d3js.org/d3.v4.js"></script>

<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>

如您所见，工具提示显示在SVG下方，正如您在问题中所描述的（如果您单击“整页” ，则可以更好地看到它）。

因此，您在该示例中缺少第三个组件： CSS！

您可以根据需要设置工具提示的样式，但这是CSS中定位工具提示的基本信息，给出了该链接中的代码：

.tooltip {
    position: absolute;
}

以下是与CSS相同的代码段：

// set the dimensions and margins of the graph
var 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
var 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
var myGroups = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J"]
var myVars = ["v1", "v2", "v3", "v4", "v5", "v6", "v7", "v8", "v9", "v10"]

// Build X scales and axis:
var 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:
var y = d3.scaleBand()
  .range([height, 0])
  .domain(myVars)
  .padding(0.01);
svg.append("g")
  .call(d3.axisLeft(y));

// Build color scale
var 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", function(data) {

  // create a tooltip
  var 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
  var mouseover = function(d) {
    tooltip.style("opacity", 1)
  }
  var mousemove = function(d) {
    tooltip
      .html("The exact value of<br>this cell is: " + d.value)
      .style("left", (d3.mouse(this)[0] + 70) + "px")
      .style("top", (d3.mouse(this)[1]) + "px")
  }
  var 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)
})

.tooltip {
  position: absolute;
}

<!DOCTYPE html>
<meta charset="utf-8">

<!-- Load d3.js -->
<script src="https://d3js.org/d3.v4.js"></script>

<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>

如您所见，工具提示现在已正确放置。

最后，仅出于完整性考虑，这是该页面中工具提示的真实CSS（请注意position）：

.tooltip {
  position: absolute;
  z-index: $zindex-tooltip;
  display: block;
  margin: $tooltip-margin;
  // Our parent element can be arbitrary since tooltips are by default inserted as a sibling of their target element.
  // So reset our font and text properties to avoid inheriting weird values.
  @include reset-text();
  font-size: $tooltip-font-size;
  // Allow breaking very long words so they don't overflow the tooltip's bounds
  word-wrap: break-word;
  opacity: 0;

  &.show { opacity: $tooltip-opacity; }

  .arrow {
    position: absolute;
    display: block;
    width: $tooltip-arrow-width;
    height: $tooltip-arrow-height;

    &::before {
      position: absolute;
      content: "";
      border-color: transparent;
      border-style: solid;
    }
  }
}

鼠标悬停定位工具提示

1 个答案: