jQuery 如何使用 Chart.js 显示折线图数据集点标签？
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How to display Line Chart dataset point labels with Chart.js?
提问by JBMcClure
I have a design requirement to display a line chart with 5 datasets of trends data. Each data value along the stroke lines need to be showing a data value label at its respective data point.
我有一个设计要求来显示带有 5 个趋势数据数据集的折线图。沿着笔划线的每个数据值都需要在其各自的数据点处显示一个数据值标签。
Unfortunately, I cannot find an option within Charts.js that will satisfy this requirement.
不幸的是，我在 Charts.js 中找不到满足此要求的选项。
Is there a workaround that can help me out?
有没有可以帮助我的解决方法？
I've posted this on fiddle too: http://jsfiddle.net/s9eannLh/
我也在小提琴上发布了这个：http: //jsfiddle.net/s9eannLh/
Thanks so much!
非常感谢！
var data = {
labels: ["","Jun 2013","Jul 2013","Aug 2013","Sep 2013","Oct 2013","Nov 2013","Dec 2013","Jan 2014","Feb 2014","Mar 2014","Apr 2014","May 2014"],
datasets: [
{
label: "hemoglobin_1",
title: "test",
fillColor: "transparent",
strokeColor: "#65204c",
pointColor: "#65204c",
pointHighlightStroke: "#FFF",
data: [null,5.7,5.7,5.8,5.7,5.8,5.7,5.9,6.7,6.7,6.5,6.4,6.4]
},
{
label: "hemoglobin_2",
fillColor: "transparent",
strokeColor: "#ed7141",
pointColor: "#ed7141",
pointHighlightStroke: "#FFF",
data: [null,15.5,15.5,15.6,15.2,15.6,15.1,15.8,17,17.4,16.8,16.4,16.4]
},
{
label: "hemoglobin_3",
fillColor: "transparent",
strokeColor: "#de4760",
pointColor: "#de4760",
pointHighlightStroke: "#FFF",
data: [null,37.1,37,37.2,37.6,36.9,37.6,36.8,37.6,38,37.5,39.1,37.5]
},
{
label: "hemoglobin_4",
fillColor: "transparent",
strokeColor: "#fdcf7e",
pointColor: "#fdcf7e",
pointHighlightStroke: "#FFF",
data: [null,29.9,30.4,29.5,29.6,30.2,29.4,29.8,26.9,27,28.5,26.8,28.5]
},
{
label: "hemoglobin_5",
fillColor: "transparent",
strokeColor: "#a33a59",
pointColor: "#a33a59",
pointHighlightStroke: "#FFF",
data: [null,11.8,11.4,11.9,11.9,11.5,12.2,11.7,11.8,10.9,10.7,11.3,11.3]
}
]
};
var options = {
responsive: true,
scaleOverride: true,
scaleSteps: 10,
scaleStepWidth: 5,
scaleStartValue: 0,
showTooltips: false,
pointDot: true,
pointDotRadius : 6,
datasetStrokeWidth : 3,
bezierCurve : false,
scaleShowHorizontalLines: false,
scaleGridLineWidth : 2,
scaleGridLineColor : "#EEEEEE",
scaleLineWidth: 3,
scaleLineColor: "#000000",
scaleFontFamily: '"Gotham Book",sans-serif',
scaleFontSize: 18
}
var ctx = $("#myChart").get(0).getContext("2d");
var Trends = new Chart(ctx).Line(data, options);
采纳答案by JBMcClure
I was able to finally find the solution to this question.
我终于找到了这个问题的解决方案。
I realized I had access to the chart object within the DOM:
我意识到我可以访问 DOM 中的图表对象：
Trends.datasets
Within each of the five datasets there was a points object containing x & y positions:
在五个数据集中的每一个中，都有一个包含 x 和 y 位置的点对象：
Trends.datasets[0..4].points
So I parsed through the points with a callback utilizing the global configuration functions in Chart.js:
所以我使用 Chart.js 中的全局配置函数通过回调解析这些点：
// Function - Will fire on animation progression.
onAnimationProgress: function(){},
// Function - Will fire on animation completion.
onAnimationComplete: function(){}
I found that I had to use onAnimationCompletewith responsive: truebecause the point labels would get wiped out on a resize event.
我发现我必须使用onAnimationCompletewithresponsive: true因为点标签会在调整大小事件中被清除。
Once I found the points within the callback, I simply wrote the labels I wanted onto the canvas.
一旦我在回调中找到了点，我只需在画布上写下我想要的标签。
My additions to the code were:
我对代码的补充是：
var options = {
onAnimationProgress: function() { drawDatasetPointsLabels() },
onAnimationComplete: function() { drawDatasetPointsLabels() }
}
With the added function:
使用附加功能：
function drawDatasetPointsLabels() {
ctx.font = '.9rem "Gotham Book",sans-serif';
ctx.fillStyle = '#AAA';
ctx.textAlign="center";
$(Trends.datasets).each(function(idx,dataset){
$(dataset.points).each(function(pdx,pointinfo){
// First dataset is shifted off the scale line.
// Don't write to the canvas for the null placeholder.
if ( pointinfo.value !== null ) {
ctx.fillText(pointinfo.value,pointinfo.x,pointinfo.y - 15);
}
});
});
}
So here is the entire code source along with the new code providing the solution:
所以这里是整个代码源以及提供解决方案的新代码：
var data = {
labels: ["","Jun 2013","Jul 2013","Aug 2013","Sep 2013","Oct 2013","Nov 2013","Dec 2013","Jan 2014","Feb 2014","Mar 2014","Apr 2014","May 2014"],
datasets: [
{
label: "hemoglobin_1",
fillColor: "transparent",
strokeColor: "#65204c",
pointColor: "#65204c",
pointHighlightStroke: "#FFF",
data: [null,5.7,5.7,5.8,5.7,5.8,5.7,5.9,6.7,6.7,6.5,6.4,6.4]
},
{
label: "hemoglobin_2",
fillColor: "transparent",
strokeColor: "#ed7141",
pointColor: "#ed7141",
pointHighlightStroke: "#FFF",
data: [null,15.5,15.5,15.6,15.2,15.6,15.1,15.8,17,17.4,16.8,16.4,16.4]
},
{
label: "hemoglobin_3",
fillColor: "transparent",
strokeColor: "#de4760",
pointColor: "#de4760",
pointHighlightStroke: "#FFF",
data: [null,37.1,37,37.2,37.6,36.9,37.6,36.8,37.6,38,37.5,39.1,37.5]
},
{
label: "hemoglobin_4",
fillColor: "transparent",
strokeColor: "#fdcf7e",
pointColor: "#fdcf7e",
pointHighlightStroke: "#FFF",
data: [null,29.9,30.4,29.5,29.6,30.2,29.4,29.8,26.9,27,28.5,26.8,28.5]
},
{
label: "hemoglobin_5",
fillColor: "transparent",
strokeColor: "#a33a59",
pointColor: "#a33a59",
pointHighlightStroke: "#FFF",
data: [null,11.8,11.4,11.9,11.9,11.5,12.2,11.7,11.8,10.9,10.7,11.3,11.3]
}
]
};
var options = {
responsive: true,
scaleOverride: true,
scaleSteps: 10,
scaleStepWidth: 5,
scaleStartValue: 0,
showTooltips: false,
pointDot: true,
pointDotRadius : 6,
datasetStrokeWidth : 3,
bezierCurve : false,
scaleShowHorizontalLines: false,
scaleGridLineWidth : 2,
scaleGridLineColor : "#EEEEEE",
scaleLineWidth: 3,
scaleLineColor: "#000000",
scaleFontFamily: '"Gotham Book",sans-serif',
scaleFontSize: 18,
onAnimationProgress: function() { drawDatasetPointsLabels() },
onAnimationComplete: function() { drawDatasetPointsLabels() }
}
var ctx = $("#myChart").get(0).getContext("2d");
var Trends = new Chart(ctx).Line(data, options);
function drawDatasetPointsLabels() {
ctx.font = '.9rem "Gotham Book",sans-serif';
ctx.fillStyle = '#AAA';
ctx.textAlign="center";
$(Trends.datasets).each(function(idx,dataset){
// First dataset is shifted off the scale line.
// Don't write to the canvas for the null placeholder.
$(dataset.points).each(function(pdx,pointinfo){
if ( pointinfo.value !== null ) {
ctx.fillText(pointinfo.value,pointinfo.x,pointinfo.y - 15);
}
});
});
}
Here is the original problematic version on jsfiddle: http://jsfiddle.net/s9eannLh
这是 jsfiddle 上有问题的原始版本：http: //jsfiddle.net/s9eannLh
[Updated link]And here is the updated solution on jsfiddle: https://jsfiddle.net/s9eannLh/82/
[更新链接]这里是 jsfiddle 的更新解决方案：https://jsfiddle.net/s9eannLh/82/
Thanks all!
谢谢大家！
回答by Cal
Here's how to do it based on the example provided on github. It looks similar to your solution...
以下是根据github上提供的示例进行操作的方法。它看起来类似于您的解决方案...
// Define a plugin to provide data labels
Chart.plugins.register({
afterDatasetsDraw: function(chart, easing) {
// To only draw at the end of animation, check for easing === 1
var ctx = chart.ctx;
chart.data.datasets.forEach(function (dataset, i) {
var meta = chart.getDatasetMeta(i);
if (!meta.hidden) {
meta.data.forEach(function(element, index) {
// Draw the text in black, with the specified font
ctx.fillStyle = 'rgb(0, 0, 0)';
var fontSize = 16;
var fontStyle = 'normal';
var fontFamily = 'Helvetica Neue';
ctx.font = Chart.helpers.fontString(fontSize, fontStyle, fontFamily);
// Just naively convert to string for now
var dataString = dataset.data[index].toString();
// Make sure alignment settings are correct
ctx.textAlign = 'center';
ctx.textBaseline = 'middle';
var padding = 5;
var position = element.tooltipPosition();
ctx.fillText(dataString, position.x, position.y - (fontSize / 2) - padding);
});
}
});
}
});
From Code: https://github.com/chartjs/Chart.js/blob/master/samples/advanced/data-labelling.html
来自代码：https: //github.com/chartjs/Chart.js/blob/master/samples/advanced/data-labelling.html
Example: http://www.chartjs.org/samples/latest/advanced/data-labelling.html
示例：http: //www.chartjs.org/samples/latest/advanced/data-labelling.html
You can also define plugins inline to the chart instead of globally...
您还可以将插件定义为内嵌到图表而不是全局...
var chart = new Chart(ctx, {
plugins: [{
afterDatasetsDraw: ...
}]
});
回答by daprezjer
In case anyone comes here looking for this as I did recently, there's a new plug in available.
如果有人像我最近一样来这里寻找这个，有一个新的插件可用。
回答by roni_eliav
Updated code for @JBMcClure solution:
@JBMcClure 解决方案的更新代码：
var data = {
labels: ["","Jun 2013","Jul 2013","Aug 2013","Sep 2013","Oct 2013","Nov 2013","Dec 2013","Jan 2014","Feb 2014","Mar 2014","Apr 2014","May 2014"],
datasets: [
{
label: "hemoglobin_1",
fillColor: "transparent",
strokeColor: "#65204c",
pointColor: "#65204c",
pointHighlightStroke: "#FFF",
data: [null,5.7,5.7,5.8,5.7,5.8,5.7,5.9,6.7,6.7,6.5,6.4,6.4]
},
{
label: "hemoglobin_2",
fillColor: "transparent",
strokeColor: "#ed7141",
pointColor: "#ed7141",
pointHighlightStroke: "#FFF",
data: [null,15.5,15.5,15.6,15.2,15.6,15.1,15.8,17,17.4,16.8,16.4,16.4]
},
{
label: "hemoglobin_3",
fillColor: "transparent",
strokeColor: "#de4760",
pointColor: "#de4760",
pointHighlightStroke: "#FFF",
data: [null,37.1,37,37.2,37.6,36.9,37.6,36.8,37.6,38,37.5,39.1,37.5]
},
{
label: "hemoglobin_4",
fillColor: "transparent",
strokeColor: "#fdcf7e",
pointColor: "#fdcf7e",
pointHighlightStroke: "#FFF",
data: [null,29.9,30.4,29.5,29.6,30.2,29.4,29.8,26.9,27,28.5,26.8,28.5]
},
{
label: "hemoglobin_5",
fillColor: "transparent",
strokeColor: "#a33a59",
pointColor: "#a33a59",
pointHighlightStroke: "#FFF",
data: [null,11.8,11.4,11.9,11.9,11.5,12.2,11.7,11.8,10.9,10.7,11.3,11.3]
}
]
};
var options = {
type: 'line',
data: data,
options: {
responsive: true,
scaleOverride: true,
scaleSteps: 10,
scaleStepWidth: 5,
scaleStartValue: 0,
showTooltips: false,
pointDot: true,
pointDotRadius : 6,
datasetStrokeWidth : 3,
bezierCurve : false,
scaleShowHorizontalLines: false,
scaleGridLineWidth : 2,
scaleGridLineColor : "#EEEEEE",
scaleLineWidth: 3,
scaleLineColor: "#000000",
scaleFontFamily: '"Gotham Book",sans-serif',
scaleFontSize: 18,
onAnimationProgress: function() { drawDatasetPointsLabels() },
onAnimationComplete: function() { drawDatasetPointsLabels() }
}
};
var ctx = document.getElementById('myChart').getContext('2d');
var Trends = new Chart(ctx, options);
function drawDatasetPointsLabels() {
ctx.font = '.9rem "Gotham Book",sans-serif';
ctx.fontWeight = 'bold';
ctx.fillStyle = '#AAA';
ctx.textAlign="center";
$(Trends.datasets).each(function(idx,dataset){
$(dataset.points).each(function(pdx,pointinfo){
if ( pointinfo.value !== null ) {
ctx.fillText(pointinfo.value,pointinfo.x,pointinfo.y - 15);
}
});
});
}
@JBMcClure Here is an updated working link:
@JBMcClure 这是一个更新的工作链接：
