D3.js：折线图 - 工具提示和悬停的垂直线 [英] D3.js: Line chart - tooltip and vertical line of hover
问题描述
我一直在研究使用D3.js构建的交互式折线图。一个悬停我想要一个工具提示显示垂直线。垂直线很好，但是，我有与工具提示有关的问题。工具提示位置不在图表上，我只获得第一个数据元素。
I have been working on an interactive line chart built using D3.js. One hover I would like a tool tip to be displayed with a vertical line. The vertical line comes out fine, however, I have problems related to the tool tip. The tool tip position is not on the graph and I am only getting the first data element.
这是我的代码：
margin = {
top: 20,
right: 20,
bottom: 20,
left: 50
};
var width = Math.max(250, Math.min(700, d3.select("#content").width- margin.left - margin.right)),
height = 500;
var vis = d3.select("#line_chart").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom);
max_x = 0, max_y = 0, min = 100;
d3.csv("line.csv", function(error, data) {
for(i=0; i < data.length; i++){
max_y = Math.max(max_y, data[i].number);
max_x = Math.max(max_x, data[i].class);
min = Math.min(min, data[i].class);
}
xScale = d3.scale.linear().range([margin.left, width - margin.right]).domain([min, max_x]),
yScale = d3.scale.linear().range([height - margin.top, margin.bottom]).domain([0, max_y]),
xAxis = d3.svg.axis()
.scale(xScale),
yAxis = d3.svg.axis()
.scale(yScale)
.orient("left");
vis.append("svg:g")
.attr("class", "x axis")
.attr("transform", "translate(0," + (height - margin.bottom) + ")")
.call(xAxis);
vis.append("svg:g")
.attr("class", "y axis")
.attr("transform", "translate(" + (margin.left) + ",0)")
.call(yAxis);
var lineGen = d3.svg.line()
.x(function(d) {
return xScale(d.class);
})
.y(function(d) {
return yScale(d.number);
})
.interpolate("basis");
var pth = vis.append('svg:path')
.attr('d', lineGen(data))
.attr('stroke', '#000')
.attr('stroke-width', 3.5)
.attr('fill', 'none');
var totalLength = pth.node().getTotalLength();
pth
.attr("stroke-dasharray", totalLength + " " + totalLength)
.attr("stroke-dashoffset", totalLength)
.transition()
.duration(2400)
.ease("linear")
.attr("stroke-dashoffset", 0);
//Line chart mouse over
var hoverLineGroup = vis.append("g")
.attr("class", "hover-line");
var hoverLine = hoverLineGroup
.append("line")
.attr("stroke", "#000")
.attr("x1", 10).attr("x2", 10)
.attr("y1", 0).attr("y2", height);
var hoverTT = hoverLineGroup.append('text')
.attr("class", "hover-tex capo")
.attr('dy', "0.35em");
var cle = hoverLineGroup.append("circle")
.attr("r", 4.5);
var hoverTT2 = hoverLineGroup.append('text')
.attr("class", "hover-text capo")
.attr('dy', "0.35em");
hoverLineGroup.style("opacity", 1e-6);
var rectHover = vis.append("rect")
.data(data)
.attr("class", "overlay")
.attr("width", width)
.attr("height", height);
rectHover
.on("mouseout", hoverMouseOff)
.on("mousemove", hoverMouseOn);
function hoverMouseOn(d) {
var mouse_x = d3.mouse(this)[0];
var mouse_y = d3.mouse(this)[1];
var graph_y = yScale.invert(mouse_y);
var graph_x = xScale.invert(mouse_x);
hoverTT.text("Marks: " + Math.round(graph_x * 100)/100);
hoverTT.attr('x', mouse_x + 10);
hoverTT.attr('y', yScale(d.class));
hoverTT2.text("Frequency: " + Math.round(d.number * 100)/100)
.attr('x', mouse_x + 10)
.attr('y', yScale(d.class) +15);
cle
.attr('x', mouse_x)
.attr('y', mouse_y);
hoverLine.attr("x1", mouse_x).attr("x2", mouse_x)
hoverLineGroup.style("opacity", 1);
}
function hoverMouseOff() {
hoverLineGroup.style("opacity", 1e-6);
};
});
}
数据：
class,number
25,1
30,7
35,11
45,13
50,21
55,23
60,30
65,41
75,39
80,24
85,14
90,4
95,8
100,2
我无法弄清楚是什么问题是。
I am not able to figure out what the issue is.
我该如何解决这个问题？
How can I solve this?
提前致谢。
编辑：以下是工作代码： https://jsfiddle.net/kan83q0m/ 1 /
Here is the working code: https://jsfiddle.net/kan83q0m/1/
推荐答案
在hoverMouseOn方法中，变量d未定义。您需要使用d3.bisector查找最接近的数据点，如下所示：
In your hoverMouseOn method, the variable d is undefined. You'll need to use d3.bisector to find the closest data point, like this:
var bisectDate = d3.bisector(function(d) { return d.class; }).left;
var mouseDate = xScale.invert(mouse_x);
var i = bisectDate(data, mouseDate);
var d0 = data[i - 1]
var d1 = data[i];
var d = mouseDate - d0[0] > d1[0] - mouseDate ? d1 : d0;
另外，我把mousemove监听器放在'vis'而不是'rectHover'上：
Also, I put the mousemove listener on 'vis' instead of 'rectHover':
vis
.on("mouseout", hoverMouseOff)
.on("mousemove", hoverMouseOn);
并使用d.number而不是d.class作为y值。如果您希望工具提示始终在线上变得有点复杂。 这是一个工作小提琴。
and used d.number instead of d.class for the y values. If you want the tooltip to always be on the line it gets a bit more complicated. Here's a working fiddle.
可以更轻松地将工具提示放在您的鼠标坐标上就像这个小提琴一样。
Might be easier to just put the tooltip at your mouse coordinates like in this fiddle.
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