javascript - 实时更新人力车图

Question

我正在尝试使用 Rickshaw 创建一个漂亮的占位符图表，显示随机数据的实时更新，如下所示:

var series = [[], []];
var random = new Rickshaw.Fixtures.RandomData(150);

for(var i = 0; i < 80; i++) {
    random.addData(series);
}

var throughput = new Rickshaw.Graph( {
    element: document.querySelector("#throughput_chart"),
    width: "300",
    height: "200",
    renderer: "line",
    series: [{
        color: "gold",
        data: series[0]
    }]
});

var alerts = new Rickshaw.Graph( {
    element: document.querySelector("#alerts_chart"),
    width: "300",
    height: "200",
    renderer: "line",
    series: [{
        color: "red",
        data: series[1]
    }]
});

throughput.render();
alerts.render();

setInterval(function() {
    random.addData(series);
    throughput.update();
    alerts.update();
    /* XXX: This causes the data to stop drawing properly
    series.forEach(function(s) {
        s.shift();
    });
    */
}, 1000);

这有效，除了注释掉的部分。事实上，它不断添加数据，这意味着图表变得越来越拥挤。我希望每次在末尾添加一个新项目时都能够删除第一个项目，以便使图形具有相同数量的数据点，但是当我将该代码放入其中时，很快就会导致图形不显示任何数据，即使 console.log 显示数组仍然充满数据。

我怎样才能让它工作，以便我一次只显示固定数量的数据点？

Answer 1

在 Rickshaw ( http://code.shutterstock.com/rickshaw/examples/fixed.html ) 文档中的例子的引导下，我拼凑了一些与您需要的类似的东西:

JS FIDDLE

var tv = 50;

var throughput = new Rickshaw.Graph({
    element: document.querySelector("#throughput_chart"),
    width: "300",
    height: "200",
    renderer: "line",
    series: new Rickshaw.Series.FixedDuration([{
        name: 'one', color: 'gold'
    }], undefined, {
        timeInterval: tv,
        maxDataPoints: 100,
        timeBase: new Date().getTime() / 1000
    })
});

var alerts = new Rickshaw.Graph({
    element: document.querySelector("#alerts_chart"),
    width: "300",
    height: "200",
    renderer: "line",
    series: new Rickshaw.Series.FixedDuration([{
        name: 'one', color: 'red'
    }], undefined, {
        timeInterval: tv,
        maxDataPoints: 100,
        timeBase: new Date().getTime() / 1000
    })
});

for(var i = 0; i < 100; i++){
    addRandomData(throughput);
    addRandomData(alerts);
}

throughput.render();
alerts.render();

setInterval(function () {

    addRandomData(throughput);
    addRandomData(alerts);
    throughput.render();
    alerts.render();

}, tv);

function addRandomData(chart) {
    var data = {
        one: Math.floor(Math.random() * 40) + 120
    };
    chart.series.addData(data);
}