我创建了两个 x,y 数组,然后使用它们执行了两个图表。我只想在红色图表中写一些文字。我想使用 (x,y) 坐标来确定文本区域。 我尝试使用 Chartjs Global 插件,但它会导致在所有图表中写入文本。我要求只发短信给一张图表。 我无法在脚本中的 Chartjs mono 插件中取得成功。 请帮助我。
这是我的代码:
<!DOCTYPE html>
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<html>
<head>
<meta name="viewport" content="width=device-width" />
<title>Index</title>
</head>
<body>
<div class="w3-row">
<div class="w3-col s3"><p></p></div>
<div class="w3-col s6" align="center"><canvas id="myChart" height="120"></canvas></div>
<div class="w3-col s3"><p></p></div>
</div>
<div class="w3-row">
<div class="w3-col s3"><p></p></div>
<div class="w3-col s6" align="center"><canvas id="myTau" height="120"></canvas></div>
<div class="w3-col s3"><p></p></div>
</div>
</body>
</html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.2/Chart.bundle.min.js"></script>
<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="03606b6271772d697043312d3b2d33" rel="noreferrer noopener nofollow">[email protected]</a>"></script>
<script type="text/javascript">
var xCoord = new Array(1997, 2003, 2005, 2009, 2014, 2018, 2019);
var yCoord = new Array(1, 3, 5, 3, 6, 10, 9);
var c = [];
for (var i = 0; i < xCoord.length; i++) {
var obj = { x: xCoord[i], y: yCoord[i] };
c.push(obj);
}
var ctx = document.getElementById('myChart').getContext('2d');
var myChart = new Chart(ctx, {
type: 'line',
data: {
datasets: [{
label: 'None',
data: c,
borderWidth: 1,
borderColor: "#3e95cd",
fill: false,
cubicInterpolationMode: 'monotone'
}
]
},
options: {
title: {
display: true,
text: 'My Chart'
},
tooltips: {
mode: 'nearest',
intersect: true
},
scales: {
xAxes: [{
type: 'linear',
position: 'bottom',
scaleLabel: {
display: true,
labelString: 'Year Assembly',
fontSize: 14
}
}],
yAxes: [{
scaleLabel: {
display: true,
labelString: 'Aquifer Values',
fontSize: 15
}
}]
}
}
});
</script>
<script type="text/javascript">
var xCoord = new Array(1997, 2003, 2005, 2009, 2014, 2018, 2019);
var yCoord = new Array(41, 31, 11, 31, 88, 101, 91);
var c = [];
for (var i = 0; i < xCoord.length; i++) {
var obj = { x: xCoord[i], y: yCoord[i] };
c.push(obj);
}
var ctx = document.getElementById('myTau').getContext('2d');
var myTau = new Chart(ctx, {
type: 'line',
data: {
datasets: [{
label: 'None',
data: c,
borderWidth: 1,
borderColor: "#ef1414",
fill: false,
cubicInterpolationMode: 'monotone'
}
]
},
options: {
title: {
display: true,
text: 'My Chart 2'
},
tooltips: {
mode: 'nearest',
intersect: true
},
scales: {
xAxes: [{
type: 'linear',
position: 'bottom',
scaleLabel: {
display: true,
labelString: 'Year Assembly',
fontSize: 14
}
}],
yAxes: [{
scaleLabel: {
display: true,
labelString: 'Aquifer Values Corresponding',
fontSize: 15
}
}]
}
}
});
</script>
更新:
这是另一个问题:
有没有办法通过chartjs坐标系来指定文本位置,而不是“宽度。,高度。”?
比如根据xCoord & yCoord数组,是否可以设置ctx.fillText x,y坐标的位置:
而不是 ctx.fillText("s(A)", 宽度 * .28, 高度 * .70);可以是这样的: ctx.fillText("s(A)", 2005, 3); (2015,9)属于chartjs坐标系。
我的目标: s(A) 可以在 Chartjs 区域的 (2005,3) 处看到 s(A)可以在chartjs区域上看到(2015,9)
这是最后一个问题代码:
<!DOCTYPE html>
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<html>
<head>
<meta name="viewport" content="width=device-width" />
<title>Index</title>
</head>
<body>
<div class="w3-row">
<div class="w3-col s3"><p></p></div>
<div class="w3-col s6" align="center"><canvas id="myChart" height="120"></canvas></div>
<div class="w3-col s3"><p></p></div>
</div>
<div class="w3-row">
<div class="w3-col s3"><p></p></div>
<div class="w3-col s6" align="center"><canvas id="myTau" height="120"></canvas></div>
<div class="w3-col s3"><p></p></div>
</div>
</body>
</html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.2/Chart.bundle.min.js"></script>
<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="c2a1aaa3b0b6eca8b182f0ecfaecf2" rel="noreferrer noopener nofollow">[email protected]</a>"></script>
<script type="text/javascript">
var plugin = {
beforeDraw: function (chart) {
var width = chart.chart.width,
height = chart.chart.height,
ctx = chart.chart.ctx;
ctx.restore();
ctx.font = "1em sans-serif";
ctx.textAlign = "center";
ctx.textBaseline = "middle";
ctx.fillText("s(A)", width * .28, height * .70);
ctx.fillText("s(B)", width * .75, height * .55);
//These section were set according to canvas width and height
//I want to set coordinates chartjs coordinates like in data {x:1993,y:70}
// Doesnt Work Like This: ctx.fillText("s(A)", 2005, 2);
//Doesnt Work Like This: ctx.fillText("s(B)", 2015, 9);
ctx.save();
}
};
Chart.plugins.register(plugin);
var xCoord = new Array(1997, 2003, 2005, 2009, 2014, 2018, 2019);
var yCoord = new Array(1, 3, 5, 3, 6, 10, 9);
var c = [];
for (var i = 0; i < xCoord.length; i++) {
var obj = { x: xCoord[i], y: yCoord[i] };
c.push(obj);
}
var ctx = document.getElementById('myChart').getContext('2d');
var myChart = new Chart(ctx, {
type: 'line',
data: {
datasets: [{
label: 'None',
data: c,
borderWidth: 1,
borderColor: "#3e95cd",
fill: false,
cubicInterpolationMode: 'monotone'
}
]
},
options: {
plugins: [plugin],
title: {
display: true,
text: 'My Chart'
},
tooltips: {
mode: 'nearest',
intersect: true
},
scales: {
xAxes: [{
type: 'linear',
position: 'bottom',
scaleLabel: {
display: true,
labelString: 'Year Assembly',
fontSize: 14
}
}],
yAxes: [{
scaleLabel: {
display: true,
labelString: 'Aquifer Values',
fontSize: 15
}
}]
}
}
});
</script>
最佳答案
一个工作示例:
var plugin = {
id: 'plugin',
beforeDraw: function(chart) {
var width = chart.chart.width,
height = chart.chart.height,
ctx = chart.chart.ctx,
xScale = chart.scales['x-axis-0'],
yScale = chart.scales['y-axis-0'];
ctx.restore();
ctx.font = "1em sans-serif";
ctx.textAlign = "center";
ctx.textBaseline = "middle";
// ctx.fillText("s(A)", width * .28, height * .70);
ctx.fillText(
"s(A)",
xScale.getPixelForValue('2005'),
yScale.getPixelForValue(3)
);
ctx.fillText(
"s(B)",
xScale.getPixelForValue('2015'),
yScale.getPixelForValue(9)
);
ctx.save();
}
};
var xCoord = new Array(1997, 2003, 2005, 2009, 2014, 2018, 2019);
var yCoord = new Array(1, 3, 5, 3, 6, 10, 9);
var c = [];
for (var i = 0; i < xCoord.length; i++) {
var obj = {
x: xCoord[i],
y: yCoord[i]
};
c.push(obj);
}
var ctx = document.getElementById('myTau').getContext('2d');
var myTau = new Chart(ctx, {
type: 'line',
data: {
datasets: [{
label: 'None',
data: c,
borderWidth: 1,
borderColor: "#ef1414",
fill: false,
cubicInterpolationMode: 'monotone'
}]
},
plugins: [plugin],
options: {
title: {
display: true,
text: 'My Chart 2'
},
tooltips: {
mode: 'nearest',
intersect: true
},
scales: {
xAxes: [{
type: 'linear',
position: 'bottom',
scaleLabel: {
display: true,
labelString: 'Year Assembly',
fontSize: 14
}
}],
yAxes: [{
scaleLabel: {
display: true,
labelString: 'Aquifer Values Corresponding',
fontSize: 15
}
}]
}
}
});
var ctx = document.getElementById('myTax').getContext('2d');
var myTau = new Chart(ctx, {
type: 'line',
data: {
datasets: [{
label: 'None',
data: c,
borderWidth: 1,
borderColor: "#ef1414",
fill: false,
cubicInterpolationMode: 'monotone'
}]
},
options: {
title: {
display: true,
text: 'My Chart 2'
},
tooltips: {
mode: 'nearest',
intersect: true
},
scales: {
xAxes: [{
type: 'linear',
position: 'bottom',
scaleLabel: {
display: true,
labelString: 'Year Assembly',
fontSize: 14
}
}],
yAxes: [{
scaleLabel: {
display: true,
labelString: 'Aquifer Values Corresponding',
fontSize: 15
}
}]
}
}
});
<canvas id="myTau" height="120"></canvas>
<canvas id="myTax" height="120"></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.8.0/Chart.bundle.min.js"></script>
<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
创建并注册一个新的插件
来绘制文本,然后仅在第二个图表上调用它,您也可以传递数据(例如标签数组和每个标签的位置) .
更新:(注册插件)
如果您全局注册一个插件,则必须在此处禁用您不希望其运行的每个图表中的插件。
options: {
plugins: {
plugin: false
}
}
- 或 -
如果您没有全局注册插件,则在需要添加标签的每个图表中添加以下内容:
{
plugins: [plugin]
}
注意:在第二个代码片段中,plugin
未嵌套在options
下。已看过 here .
更新:(使用 x,y
数据集显示文本)
为了使用 x,y
值,您需要使用其 id 来识别该值的轴,默认值为 x-axis-0
和y-axis-0
,如果添加更多轴,该值就会递增。或者使用自定义轴 ID。
之后,在 chart
实例中,有一个代表轴的比例对象,使用 chart.scales['x-axis-0']
您可以访问一个名为 getPixelForValue
的函数,它将把给定值从该轴转换为其像素位置。
关于asp.net-core - 将文本放置在 ChartJS 的图表 Canvas 区域中,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/55950872/