d3.js中具有特定时区的时间轴 [英] Time axis in d3.js with specific time zone
问题描述
我正在使用 d3.time.scale（）（参考此处）创建时间刻度并使用 axis.tickValues（[values]）（此处）。将为[values]中提供的指定Date对象渲染刻度线。
很好，但是滴答值表示始终在浏览器的当前时区。现在，要求在特定时区（例如，亚洲/ Calcutta）显示它。有没有办法做到这一点？我看到的最大选项是设置刻度线的格式，但不能用自定义值替换它们，这无济于事。
I am using d3.time.scale()(reference here) to create time scale and providing tick values using axis.tickValues([values]) (here). The ticks are rendered for the specified Date objects provided in [values].
All fine, but the tick values representations are always in current time zone of the browser. Now comes the requirement to show it in a specific time zone (say, 'Asia/Calcutta'). Is there a way to achieve this? The max option I see is for formatting the ticks, but not replacing them with custom values, which doesn't help the case.
编辑 ：可以使用 moment.js 之类的外部库来实现，但是如果可以避免，则是首选方法。
EDIT: This might be achieved using an external library like moment.js, but it is preferred if this could be avoided.
推荐答案
时区实在是太麻烦了。但是，如果您将 d3 与出色的瞬间时区结合在一起，使用 tickformatter 函数可以轻松完成此任务：
Timezones are such a pain in the ass. But if you couple d3 with the the excellent moment timezone, this task becomes pretty easy with a tickformatter function:
// create reference to current zone
var currentTZ = "local";
// Define the axes
var xAxis = d3.svg.axis().scale(x)
.orient("bottom").ticks(10)
.tickFormat(function(d){
console.log('format');
if (currentTZ === "local")
return moment(d).format('hh:mm:ss');
else
return moment(d).tz(currentTZ).format('hh:mm:ss');
});
// when user picks a new zone, re-draw axis
...
.append("select")
.on('change', function(d){
currentTZ = this.options[ this.selectedIndex ].text;
svg.selectAll("g.x.axis")
.call(xAxis);
})
下面是一个完整的示例：
Here's a full working example:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<script data-require="moment.js@2.10.2" data-semver="2.10.2" src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.10.2/moment.min.js"></script>
<script data-require="moment-timezone-with-data@0.4.0" data-semver="0.4.0" src="http://momentjs.com/downloads/moment-timezone-with-data.js"></script>
<style>
/* set the CSS */
body {
font: 12px Arial;
}
path {
stroke: steelblue;
stroke-width: 2;
fill: none;
}
.axis path,
.axis line {
fill: none;
stroke: grey;
stroke-width: 1;
shape-rendering: crispEdges;
}
</style>
</head>
<body>
<!-- load the d3.js library -->
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>
// Set the dimensions of the canvas / graph
var margin = {
top: 30,
right: 20,
bottom: 100,
left: 50
},
width = 600 - margin.left - margin.right,
height = 270 - margin.top - margin.bottom;
var currentTZ = "local";
// Set the ranges
var x = d3.time.scale().range([0, width]);
var y = d3.scale.linear().range([height, 0]);
// Define the axes
var xAxis = d3.svg.axis().scale(x)
.orient("bottom").ticks(10)
.tickFormat(function(d){
console.log('format');
if (currentTZ === "local")
return moment(d).format('hh:mm:ss');
else
return moment(d).tz(currentTZ).format('hh:mm:ss');
});
var yAxis = d3.svg.axis().scale(y)
.orient("left").ticks(5);
// Define the line
var valueline = d3.svg.line()
.x(function(d) {
return x(d.date);
})
.y(function(d) {
return y(d.close);
});
// Adds the svg canvas
var svg = d3.select("body")
.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 + ")");
var data = [{
date: moment().add(0, 'hours').toDate(),
close: Math.random() * 100
}, {
date: moment().add(1, 'hours').toDate(),
close: Math.random() * 100
}, {
date: moment().add(2, 'hours').toDate(),
close: Math.random() * 100
}, {
date: moment().add(3, 'hours').toDate(),
close: Math.random() * 100
}, {
date: moment().add(4, 'hours').toDate(),
close: Math.random() * 100
}, {
date: moment().add(5, 'hours').toDate(),
close: Math.random() * 100
}, {
date: moment().add(6, 'hours').toDate(),
close: Math.random() * 100
}, {
date: moment().add(7, 'hours').toDate(),
close: Math.random() * 100
}]
// Scale the range of the data
x.domain(d3.extent(data, function(d) {
return d.date;
}));
y.domain([0, d3.max(data, function(d) {
return d.close;
})]);
// Add the valueline path.
svg.append("path")
.attr("class", "line")
.attr("d", valueline(data));
// Add the X Axis
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis)
.selectAll("text")
.style("text-anchor", "end")
.attr("dx", "-.8em")
.attr("dy", ".15em")
.attr("transform", function(d) {
return "rotate(-65)"
});
// Add the Y Axis
svg.append("g")
.attr("class", "y axis")
.call(yAxis);
d3.select("body")
.append("select")
.on('change', function(d){
currentTZ = this.options[ this.selectedIndex ].text;
svg.selectAll("g.x.axis")
.call(xAxis)
.selectAll("text")
.style("text-anchor", "end")
.attr("dx", "-.8em")
.attr("dy", ".15em")
.attr("transform", function(d) {
return "rotate(-65)"
});
})
.selectAll("option")
.data(['local'].concat(moment.tz.names()))
.enter()
.append("option")
.text(function(d){
return d;
});
</script>
</body>
</html>
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