我设置了一个chart.js图表,它使用mysql数据库中的数据。我已经建立了一个rest服务来提供tha数据,具有定义分组IE的能力。数据每隔5分钟测量一次,但我将其分组为3小时段,使用我的SQL语句select(75-round(avg(sensorValue),0))作为值,从sensorpi.rawdata组按UNIX_TIMESTAMP(Time)DIV$default_interval顺序按Time asc
我希望能够通过定义一个新的粒度来改变数据的粒度。
我创建了一个更新函数来将请求发送到后端,并更新图表。
图表已更新,但默认值有61个条目(目前),最细粒度的数据有180个条目。所发生的情况是,数据只是减少到数据集中的前61项。
我的直觉是X轴的日期标签造成了麻烦。但我不知如何解决。
下面是一个MVE(也在jsfiddle:https://jsfidle.net/0agcu3ps/2/)
var data05 = [1, 2, 5, 7, 16];
var data10 = [1,2,3,4,5,6,7,8,12,16];
var labels05 = [
"Mon Nov 12 2018 02:00:00 GMT+0100",
"Mon Nov 12 2018 12:00:00 GMT+0100",
"Tue Nov 13 2018 18:00:00 GMT+0100",
"Wed Nov 14 2018 02:00:00 GMT+0100",
"Thu Nov 15 2018 14:00:00 GMT+0100"];
var labels10 = [
"Tue Nov 12 2018 02:00:00 GMT+0100",
"Mon Nov 12 2018 10:00:00 GMT+0100",
"Mon Nov 12 2018 12:00:00 GMT+0100",
"Tue Nov 13 2018 14:00:00 GMT+0100",
"Tue Nov 13 2018 18:00:00 GMT+0100",
"Tue Nov 13 2018 20:00:00 GMT+0100",
"Wed Nov 14 2018 02:00:00 GMT+0100",
"Wed Nov 14 2018 10:00:00 GMT+0100",
"Thu Nov 15 2018 12:00:00 GMT+0100",
"Thu Nov 15 2018 14:00:00 GMT+0100"];
window.updateChartData = function() {
var newData = [];
var newLabels =[];
var intrval = document.getElementById("interval").value;
if(intrval == 5){
newData = data05;
}else if (intrval == 10) {
newData = data10;
}
pilleChart.data.datasets[0].data = newData;
pilleChart.data.datasets[0].labels = newLabels;
console.log("updating chart");
pilleChart.update();
}
function drawLineChart() {
// Create the chart.js data structure using 'labels' and 'data'
var pilleData = {
labels: labels05,
datasets: [{
fillColor: "rgba(151,187,205,0.2)",
strokeColor: "rgba(200,200,205,0.7)",
borderColor: "rgba(151,187,205,0.9)",
borderWidth: 1,
fill: false,
label: 'Pilleniveau',
data: data05
}
]
};
var options = {
showLines: true,
responsive: true,
title: {
display: true,
text: 'Pilleniveau i beholder'
},
legend: {
display: false
},
tooltips: {
mode: 'index',
intersect: true
},
annotation: {
annotations: [{
type: 'line',
mode: 'horizontal',
scaleID: 'y-axis-0',
value: 2,
borderColor: "rgba(200,170,150,1)",
borderWidth: 2,
label: {
enabled: false,
content: 'Test label'
}
}
]
},
scales: {
yAxes: [{
ticks: {
beginAtZero: true
}
}
],
//Set X-Axis to date instead of labels
xAxes: [{
type: 'time',
time: {
unit: 'day'
}
}
]
}
}
var ctx = document.getElementById("pilleChart").getContext("2d");
// Instantiate a new chart
pilleChart = new Chart(ctx, {
type: 'line',
data: pilleData,
options: options
});
}
drawLineChart();
编辑:我一直在阅读chart.js--Update()与时间刻度数据集,并与发帖人进行了交流,发帖人分享了他的解决方案,该方案本质上是销毁图表并重新绘制它。我对这种方法不满意...
似乎有一种黑客手段:
pilleChart.config.data.labels = newLabels
参见:https://jsfidle.net/0agcu3ps/3/
ps:您的演示有一个bug,var labels10=[“Tue Nov 13 2018 02:00:00 GMT+0100”,
第一项错误,应该是Nov 12
:d