javascript - 在动态生成的图表中为最大值添加颜色？

Question

jsfiddle 链接在这里 http://jsfiddle.net/MzQE8/110/

我觉得这里的问题出在我的 JavaScript 中。

我将值从数组输入到 HighChart 中的系列对象。在数组上，我试图找到索引和最大元素的值，然后通过此修改将最大数组元素保存回来

                        yArr[index] = {
                            y: value,
                            color: '#aaff99'
                        };

因此它显示为与动态图上其余点不同的颜色。这是它的滑动部分。

这是我的代码

$(function () {
 $(document).ready(function () {
    Highcharts.setOptions({
        global: {
            useUTC: false
        }
    });

    var chart;

    $('#container').highcharts({
        chart: {
            type: 'spline',
            animation: Highcharts.svg, // don't animate in old IE
            marginRight: 10,
            events: {
                load: function () {

                    // set up the updating of the chart each second
                    var series = this.series[0];
                   //As this graph is generated due to random values. I am creating an Array with random values.
                    var yArr = [];
                    yArr[0] = Math.random();

                    yArr[1] = Math.random();

                    yArr[2] = Math.random();

                    yArr[3] = Math.random();



                    setInterval(function () {
                        console.log(yArr.length);
                        var x = (new Date()).getTime(), // current time
                            y = Math.random();
                        var index = findIndexOfGreatest(yArr);
                        var value = yArr[index];
                        yArr[index] = {
                            y: value,
                            color: '#aaff99'
                        };
                        series.addPoint([x, yArr.shift()], true, true);
                        yArr.push(Math.random());

                    }, 1000);
                }
            }
        },
        title: {
            text: 'Live random data'
        },
        xAxis: {
            type: 'datetime',
            tickPixelInterval: 450
        },
        yAxis: {
            title: {
                text: 'Value'
            },
            plotLines: [{
                value: 0,
                width: 1,
                color: '#808080'
            }]
        },
        plotOptions: {

            series: {
                lineWidth: 1
            }
        },
        tooltip: {
            formatter: function () {
                return '<b>' + this.series.name + '</b><br/>' + Highcharts.dateFormat('%Y-%m-%d %H:%M:%S', this.x) + '<br/>' + Highcharts.numberFormat(this.y, 2);
            }
        },
        legend: {
            enabled: false
        },
        exporting: {
            enabled: false
        },
        series: [{
            name: 'Random Data',
            data: (function () {
                // generate an array of random data
                var data = [],
                    time = (new Date()).getTime(),
                    i;

                for (i = -19; i <= 0; i++) {
                    data.push({
                        x: time + i * 1000,
                        y: yArr.shift()
                    });
                }
                return data;
            })(),
            color: 'red'
        }]
    });
});

function findIndexOfGreatest(array) {
    var greatest;
    var indexOfGreatest;
    for (var i = 0; i < array.length; i++) {
        if (!greatest || array[i] > greatest) {
            greatest = array[i];
            indexOfGreatest = i;
        }
    }
    return indexOfGreatest;
}

});

我觉得我的想法是正确的，但我的实现有很大的漏洞。我猜。

谢谢

Answer 1

查看演示:http://jsfiddle.net/MzQE8/350/

所有 y 值都存储在 series.yData 中，因此您不必为此创建另一个数组。现在只需更新最高点，并添加新点。类似于上面的演示，代码:

            events: {
                load: function () {

                    // set up the updating of the chart each second
                    var series = this.series[0],
                        index = series.yData.indexOf(series.yData.max());

                    // mark first max points
                    this.series[0].prevMax = this.series[0].data[index];
                    this.series[0].prevMax.update({
                        color: '#aaff99'
                    });

                    setInterval(function () {
                        var x = (new Date()).getTime(), // current time
                            y = Math.random(),
                            color = null,
                            index, max;
                        if (series.prevMax && series.prevMax.update) {
                            // remove previously colored point
                            if (y > series.prevMax.y) {
                                series.prevMax.update({
                                    color: null
                                }, false);
                                color = '#aaff99';

                                // store max, which is last point
                                series.prevMax = series.data[series.yData.length]; 
                            }
                        } else {
                            max = series.yData.max();
                            index = series.yData.indexOf(max);

                            if(y > max) {
                               color = '#aaff99'; 
                               series.prevMax = series.data[series.yData.length];     
                            } else {
                                series.prevMax = series.data[index]; 
                                series.prevMax.update({
                                    color: '#aaff99'
                                }, false)
                            }
                        }

                        // add new point
                        series.addPoint({
                            x: x,
                            y: y,
                            color: color
                        }, true, true);

                    }, 1000);
                }
            }