如何强制我的 ChartJS 画布图例留在单个列中？
Posted
技术标签:
【中文标题】如何强制我的 ChartJS 画布图例留在单个列中？【英文标题】：How can I force my ChartJS canvas legend to stay in a single column? 【发布时间】：2019-06-09 15:52:06 【问题描述】：我检查了一些不同的来源并查看了选项，但我似乎无法让我的图例留在一栏中。例如，
在上图中，您会注意到图例的一部分被切掉并放在一边。这发生在 https://jsfiddle.net/lochrine/02yrpcxg/
这里是相关的JS：
//Line Graph Script
$('.line-graph').each(function ()
var legendlabels = $(this).data('legendlabels');
var datapoints = $(this).data('datapoints');
var suppliers = $(this).data('suppliers');
var datatype = $(this).data('datatype');
var yAxisString = "Amounts";
if (datatype == "units") yAxisString = "Units Sold";
else if (datatype == "money") yAxisString = "Amount (Dollars)";
console.log(datatype);
new Chart($(this).get(0).getContext('2d'),
type: 'line',
data:
labels: legendlabels,
datasets: $.map(datapoints, function (e, i)
return
backgroundColor: lineChartColors[i],
borderColor: lineChartColors[i],
fill: false,
data: e,
label: suppliers[i],
lineTension: 0.2,
)
,
options:
layout:
padding:
left: 20,
right: 40,
top: 20,
bottom: 20
,
legend:
display: true,
position: 'left'
,
scales:
xAxes: [
scaleLabel:
display: true,
labelString: 'Month'
],
yAxes: [
ticks:
beginAtZero: true,
callback: function (value, index, values)
return addCommas(value);
,
scaleLabel:
display: true,
labelString: yAxisString
]
,
plugins:
datalabels:
display: false
,
tooltips:
callbacks:
label: function (tooltipItem, data)
var datasetLabel = data.datasets[tooltipItem.datasetIndex].data[tooltipItem.index].toString();
var label = data.datasets[tooltipItem.datasetIndex].label + ': ';
var formattedReturnLabel;
if (datatype == "money")
formattedReturnLabel = label + '$' + addCommas(datasetLabel);
else
formattedReturnLabel = label + addCommas(datasetLabel);
return formattedReturnLabel;
);
)
以及相关的html：
<div class="widget widget-double">
<div class="m-3 border">
<table style="cursor: pointer !important;" onclick="window.location.href='@Url.Action("SupplierUnitsByMonth", "Reports")'" class="table mb-0"><thead><tr><th class="text-center">@ViewBag.widgetName</th></tr></thead></table>
<div class="w-100 aspect-ratio-50 p-2">
<canvas id="chart-units-history" data-legendlabels="[@ViewBag.Months]" data-suppliers= "[@ViewBag.suppliers]" data-datapoints="[@ViewBag.supplierTotals]" data-datatype="units" class="line-graph w-100 aspect-ratio-50"></canvas>
</div>
</div>
</div>
【问题讨论】：
【参考方案1】：您可以使用legendCallback 和一些CSS 生成自定义HTML legend。
legendCallback: chart =>
let html = '<ul>';
chart.data.datasets.forEach((ds, i) =>
html += '<li>' +
'<span style="width: 36px; height: 14px; background-color:' + ds.backgroundColor + '; border:' + ds.borderWidth + 'px solid ' + ds.borderColor + '" onclick="onLegendClicked(event, \'' + i + '\')"> </span>' +
'<span id="legend-label-' + i + '" onclick="onLegendClicked(event, \'' + i + '\')">' +
ds.label + '</span>' +
'</li>';
);
return html + '</ul>';
,
为了使其行为与标准 Chart.js 图表相同，当鼠标单击图例标签时会调用函数
onLegendClicked。此功能切换单个数据集的隐藏状态，并在正常和删除线之间更改标签文本样式。
function onLegendClicked(e, i)
const hidden = !chart.data.datasets[i].hidden;
chart.data.datasets[i].hidden = hidden;
const legendLabelSpan = document.getElementById("legend-label-" + i);
legendLabelSpan.style.textDecoration = hidden ? 'line-through' : '';
chart.update();
;
请查看您修改后的代码，看看它是如何工作的。
const lineChartColors = ["#000000", "#fd7730", "#ffd35c", "#3fc6f3", "#28a745", "#488cf2", "#4755d3", "#9768c9", "#f2748d", "#f287e7", '#992499', '#6BD69E'];
const legendlabels = ['Aug', 'Sep', 'Oct', 'Nov', 'Dec', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul'];
const datapoints = [
[205, 275, 359, 329, 262, 302, 290, 323, 279, 238, 307, 245],
[16, 13, 14, 11, 23, 11, 24, 23, 15, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 53, 0],
[169, 194, 261, 193, 151, 158, 128, 143, 163, 173, 139, 208],
[8, 5, 8, 2, 4, 4, 0, 0, 0, 0, 0, 0],
[0, 0, 19, 36, 7, 35, 27, 30, 13, 0, 0, 0],
[0, 47, 30, 54, 59, 48, 41, 38, 65, 24, 44, 37],
[12, 16, 27, 33, 18, 46, 70, 89, 23, 41, 71, 0]
];
var suppliers = ["Total", "Starkey", "Resound", "Widex", "Rexton", "Unitron", "Phonak", "Signia"];
function onLegendClicked(e, i)
const hidden = !chart.data.datasets[i].hidden;
chart.data.datasets[i].hidden = hidden;
const legendLabelSpan = document.getElementById("legend-label-" + i);
legendLabelSpan.style.textDecoration = hidden ? 'line-through' : '';
chart.update();
;
const chart = new Chart('myChart',
type: 'line',
data:
labels: legendlabels,
datasets: datapoints.map((e, i) => (
backgroundColor: lineChartColors[i],
borderColor: lineChartColors[i],
fill: false,
data: e,
label: suppliers[i],
lineTension: 0.2,
))
,
options:
legend:
display: false
,
legendCallback: chart =>
let html = '<ul>';
chart.data.datasets.forEach((ds, i) =>
html += '<li>' +
'<span style="width: 36px; height: 14px; background-color:' + ds.backgroundColor + '; border:' + ds.borderWidth + 'px solid ' + ds.borderColor + '" onclick="onLegendClicked(event, \'' + i + '\')"> </span>' +
'<span id="legend-label-' + i + '" onclick="onLegendClicked(event, \'' + i + '\')">' +
ds.label + '</span>' +
'</li>';
);
return html + '</ul>';
,
scales:
xAxes: [
scaleLabel:
display: true,
labelString: 'Month'
],
yAxes: [
ticks:
beginAtZero: true
,
scaleLabel:
display: true,
labelString: "Units Sold"
]
,
plugins:
datalabels:
display: false
);
document.getElementById("legend").innerHTML = chart.generateLegend();#chart-wrapper
display: flex;
ul
list-style-type: none;
margin: 0;
padding: 0;
#legend li
cursor: pointer;
display: flex;
padding: 0 10px 5px 0;
#legend li span
padding-left: 8px;
font-family: Arial, Helvetica, sans-serif;
font-size: 12px;
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<div id="chart-wrapper">
<div id="legend"></div>
<canvas id="myChart" ></canvas>
</div>【讨论】：
以上是关于如何强制我的 ChartJS 画布图例留在单个列中？的主要内容，如果未能解决你的问题，请参考以下文章
如何通过画布外的按钮（ChartJs）控制画布图像的可见性？