我有一个设计要求，要显示带有5个趋势数据集的折线图。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。
不幸的是，我无法在Charts.js中找到满足此要求的选项。
是否有可以帮助我的解决方法？
我也将此内容张贴在小提琴上：http://jsfiddle.net/s9eannLh/
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);
我终于能够找到这个问题的解决方案。
我意识到我可以访问DOM中的图表对象：
Trends.datasets
在五个数据集中的每个数据集中都有一个包含x和y位置的点对象：
Trends.datasets[0..4].points
所以我利用Chart.js中的全局配置函数通过回调解析了所有要点：
// Function - Will fire on animation progression.
onAnimationProgress: function(){},
// Function - Will fire on animation completion.
onAnimationComplete: function(){}
[我发现我必须将onAnimationComplete与responsive: true一起使用，因为在发生调整大小事件时，点标签会消失。
一旦在回调中找到要点，我只需将想要的标签写到画布上。
我对代码的补充是：
var options = {
onAnimationProgress: function() { drawDatasetPointsLabels() },
onAnimationComplete: function() { drawDatasetPointsLabels() }
}
具有附加功能：
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);
}
});
});
}
所以这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);
}
});
});
}
这是jsfiddle上的原始有问题的版本：http://jsfiddle.net/s9eannLh
[更新链接]这是jsfiddle的更新解决方案：https://jsfiddle.net/s9eannLh/82/
谢谢大家！
这里是基于github提供的示例的方法。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);
});
}
});
}
});
来自代码：https://github.com/chartjs/Chart.js/blob/master/samples/advanced/data-labelling.html
示例：http://www.chartjs.org/samples/latest/advanced/data-labelling.html
您还可以在图表中内联而不是在全局范围内定义插件...
var chart = new Chart(ctx, {
plugins: [{
afterDatasetsDraw: ...
}]
});
如果有人像我最近一样来这里寻找这个，会有一个新的插件可用。
@ 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，这是一个更新的工作链接：