chart.js v3:如何将网格线与步长对齐

Question

预期：在此处输入图像描述

电流：在此处输入图像描述

我想在同一行中有步长和网格线，并添加一些填充

我如何使用chart.js v3 实现这一点

scales: {
y: {
stacked: true,
grid: {
offset: true,
display: true,
drawBorder: false,
drawOnChartArea: true,
borderDashOffset: 25,
borderColor: "#d1d2db",
borderWidth: 0.8800000000000001,
color: "#d1d2db",
},
min: 0,
max: max,
ticks: {
// forces step size to be 25 units
stepSize: 25,
beginAtZero: true,
callback: callback,
max: max,
},
title: {
display: false,
text: "Y axis title",
},
},
x: {
grid: {
offset: true,
display: true,
drawBorder: false,
drawOnChartArea: false,
drawTicks: false,
tickLength: 0,
// borderDash: [0, 1],
// borderDashOffset: 0,
borderColor: "#d1d2db",
// borderWidth: 0.8800000000000001,
color: "#d1d2db",
},
},
},

顺便说一句，是否也可以如预期设计中所示，从数据点到x轴有垂线？

Answer 1

要使水平grid行与y标签对齐，请定义options.scales.y.grid.offset: false或省略该选项。

对于从图表底部到各个数据点的垂直线，您可以使用插件核心API。例如，在afterDraw挂钩中，可以使用CanvasRenderingContext2D直接在canvas上绘制线。

请看一下您修改后的可运行代码，看看它是如何工作的。

new Chart('chart', {
type: 'line',
plugins: [{
afterDraw: chart => {
var ctx = chart.ctx;
ctx.save();
var xAxis = chart.scales.x;
var yAxis = chart.scales.y;
const data = chart.data.datasets[0].data;
xAxis.ticks.forEach((v, i) => {
var x = xAxis.getPixelForTick(i);
var yTop = yAxis.getPixelForValue(data[i]);        
ctx.strokeStyle = '#aaaaaa';
ctx.beginPath();
ctx.moveTo(x, yAxis.bottom);
ctx.lineTo(x, yTop);
ctx.stroke();        
});
ctx.restore();
}
}],
data: {
labels: [1, 2, 3, 4, 5, 6, 7],
datasets: [{
label: 'My Data',
data: [65, 59, 80, 81, 56, 55, 68],
borderColor: '#0a0'
}]
},
options: {
scales: {
y: {
stacked: true,
grid: {
display: true,
drawBorder: false,
drawOnChartArea: true,
borderDashOffset: 25,
borderColor: "#d1d2db",
borderWidth: 0.8800000000000001,
color: "#d1d2db",
},
min: 0,
ticks: {
stepSize: 25,
beginAtZero: true,
},
title: {
display: false,
text: "Y axis title",
},
},
x: {
grid: {
offset: true,
display: true,
drawBorder: false,
drawOnChartArea: false,
drawTicks: false,
tickLength: 0,
borderColor: "#d1d2db",
color: "#d1d2db",
},
},
}
}
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.8.0/chart.min.js"></script>
<canvas id="chart" width="400" height="95"></canvas>