感谢这篇文章中的白帽，我能够为面积图制作自定义注释。不知何故，它不适用于阶梯面积图。
图表首先正确绘制所有内容，但随后将阶梯面积图中的注释设置回来。在MutationObserver的帮助下，绘制图表时应覆盖设置，但这仅适用于面积图。
我该如何解决这个问题？
<html>
<head>
<script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>
<script type="text/javascript">
google.charts.load('current', {
packages: ['corechart']
}).then(function () {
var data1 = new google.visualization.DataTable();
data1.addColumn('number', 'x');
data1.addColumn('number', 'green');
data1.addRows([
[0.005, 3],
[0.006, 6],
[0.007, 5],
[0.008, 8],
[0.009, 2],
[0.010, 5],
[0.011, 5],
[0.012, 4],
[0.013, 8]
]);
var data2 = new google.visualization.DataTable();
data2.addColumn('number', 'x');
data2.addColumn('number', 'red');
data2.addRows([
[0.016, 5],
[0.017, 1],
[0.018, 3],
[0.019, 9],
[0.020, 4],
[0.021, 5],
[0.022, 7],
[0.023, 7],
[0.024, 3]
]);
var joinedData = google.visualization.data.join(data1, data2, 'full',
[[0, 0]], [1], [1]);
var options = {
annotations: {
stem: {
length: 10
}
},
title: 'Playground',
colors: ['#007f01', '#fe0002'],
interpolateNulls: true,
hAxis: {
titleTextStyle: {
color: '#333'
},
direction: 1,
format: 'decimal'
},
vAxis: {
direction: 1
},
orientation: 'horizontal',
// customize colum
series: {
0: {type: "steppedArea"},
1: {type: "area"},
},
// legend: {position : 'left'},
animation: {
startup: true,
duration: 1000,
easing: 'out',
}
};
var view = new google.visualization.DataView(joinedData);
view.setColumns([0,
1,
{
calc: "stringify",
sourceColumn: 1,
type: "string",
role: "annotation"
},
2,
{
calc: "stringify",
sourceColumn: 2,
type: "string",
role: "annotation"
}
]);
var container = document.getElementById('chart_div');
var chart = new google.visualization.ComboChart(container);
var observer = new MutationObserver(moveAnnotations);
observer.observe(container, {
childList: true,
subtree: true
});
function moveAnnotations() {
var chartLayout = chart.getChartLayoutInterface();
var chartBounds = chartLayout.getChartAreaBoundingBox();
var labels = container.getElementsByTagName('text');
var labelSize = 0;
Array.prototype.forEach.call(labels, function(label) {
if (label.getAttribute('text-anchor') === 'middle') {
if (options.colors.indexOf(label.getAttribute('fill')) > -1) {
labelSize = (parseFloat(label.getAttribute('font-size')) / 2);
label.setAttribute('y', chartBounds.top + labelSize);
}
}
});
var stems = container.getElementsByTagName('rect');
Array.prototype.forEach.call(stems, function(stem) {
if ((parseInt(stem.getAttribute('height')) === options.annotations.stem.length) && (stem.getAttribute('fill') === '#999999')) {
var height = parseFloat(stem.getAttribute('y')) - chartBounds.top;
stem.setAttribute('height', height);
stem.setAttribute('y', chartBounds.top + labelSize);
}
});
}
chart.draw(view.toDataTable(), options);
});
</script>
</head>
<body>
<div id="chart_div" style="width: 100%; height: 500px;"></div>
</body>
</html>阶梯面积图的默认注释设置与普通面积图不同
对于步进，注释显示在区域内，这会将颜色更改为白色，
这不是用于查找标签和移动标签的颜色
一个简单的解决方法是指定注释始终在区域之外...
annotations: {
alwaysOutside: true,
...
请参阅以下工作片段...
google.charts.load('current', {
packages: ['corechart']
}).then(function () {
var data1 = new google.visualization.DataTable();
data1.addColumn('number', 'x');
data1.addColumn('number', 'green');
data1.addRows([
[0.005, 3],
[0.006, 6],
[0.007, 5],
[0.008, 8],
[0.009, 2],
[0.010, 5],
[0.011, 5],
[0.012, 4],
[0.013, 8]
]);
var data2 = new google.visualization.DataTable();
data2.addColumn('number', 'x');
data2.addColumn('number', 'red');
data2.addRows([
[0.016, 5],
[0.017, 1],
[0.018, 3],
[0.019, 9],
[0.020, 4],
[0.021, 5],
[0.022, 7],
[0.023, 7],
[0.024, 3]
]);
var joinedData = google.visualization.data.join(data1, data2, 'full',
[[0, 0]], [1], [1]);
var options = {
annotations: {
alwaysOutside: true,
stem: {
length: 10
}
},
title: 'Playground',
colors: ['#007f01', '#fe0002'],
interpolateNulls: true,
hAxis: {
titleTextStyle: {
color: '#333'
},
direction: 1,
format: 'decimal'
},
vAxis: {
direction: 1
},
orientation: 'horizontal',
// customize colum
series: {
0: {type: "steppedArea"},
1: {type: "area"},
},
// legend: {position : 'left'},
animation: {
startup: true,
duration: 1000,
easing: 'out',
}
};
var view = new google.visualization.DataView(joinedData);
view.setColumns([0,
1,
{
calc: "stringify",
sourceColumn: 1,
type: "string",
role: "annotation"
},
2,
{
calc: "stringify",
sourceColumn: 2,
type: "string",
role: "annotation"
}
]);
var container = document.getElementById('chart_div');
var chart = new google.visualization.ComboChart(container);
var observer = new MutationObserver(moveAnnotations);
observer.observe(container, {
childList: true,
subtree: true
});
function moveAnnotations() {
var chartLayout = chart.getChartLayoutInterface();
var chartBounds = chartLayout.getChartAreaBoundingBox();
var labels = container.getElementsByTagName('text');
var labelSize = 0;
Array.prototype.forEach.call(labels, function(label) {
if (label.getAttribute('text-anchor') === 'middle') {
if (options.colors.indexOf(label.getAttribute('fill')) > -1) {
labelSize = (parseFloat(label.getAttribute('font-size')) / 2);
label.setAttribute('y', chartBounds.top + labelSize);
}
}
});
var stems = container.getElementsByTagName('rect');
Array.prototype.forEach.call(stems, function(stem) {
if ((parseInt(stem.getAttribute('height')) === options.annotations.stem.length) && (stem.getAttribute('fill') === '#999999')) {
var height = parseFloat(stem.getAttribute('y')) - chartBounds.top;
stem.setAttribute('height', height);
stem.setAttribute('y', chartBounds.top + labelSize);
}
});
}
chart.draw(view.toDataTable(), options);
});<script src="https://www.gstatic.com/charts/loader.js"></script>
<div id="chart_div"></div>