我在Vis JS 时间轴中使用以下选项在时间轴顶部生成带有时间标签的水平轴：
orientation: {
axis: 'both'
},
水平轴如下所示：
我的时间线有很多行，所以用户需要垂直向下滚动页面才能看到所有内容。问题是向下滚动页面时顶部的水平轴不会留在视图中。
问题：如何冻结顶部的水平轴，以便在向下滚动时保持时间标签？
以下代码片段或jsfiddle.net/nj1647tb是我的时间线：
const seed = '11';
Math.seedrandom(seed);
const nGroups = 40;
const maxSubGroups = 2;
const maxItemsPerSubGroup = 1;
const metaEventCount = 2;
const itemLengthScale = 200;
let now = moment().minutes(0).seconds(0).milliseconds(0);
var groupCount = 12;
var itemCount = 70;
var tcCrashProbability = 0.2;
function randInt(min, max) {
return Math.round(min + Math.random() * (max - min));
}
function getStartEnd(earliestStart) {
if (earliestStart === undefined) {
earliestStart = 0;
}
let startAdd = earliestStart + Math.random() * 200;
let length = Math.random() * itemLengthScale;
let endAdd = startAdd + length;
return {
startAdd: startAdd,
endAdd: endAdd
}
}
const stackTrace = `Traceback (most recent call last):
File "/usr/local/lib/python3.6/site-packages/requests/adapters.py", line 449, in send
timeout=timeout
File "/usr/local/lib/python3.6/site-packages/urllib3/connectionpool.py", line 756, in urlopen
method, url, error=e, _pool=self, _stacktrace=sys.exc_info()[2]
File "/usr/local/lib/python3.6/site-packages/urllib3/util/retry.py", line 532, in increment
raise six.reraise(type(error), error, _stacktrace)
File "/usr/local/lib/python3.6/site-packages/urllib3/packages/six.py", line 769, in reraise
raise value.with_traceback(tb)
File "/usr/local/lib/python3.6/site-packages/urllib3/connectionpool.py", line 706, in urlopen
chunked=chunked,
File "/usr/local/lib/python3.6/site-packages/urllib3/connectionpool.py", line 445, in _make_request
six.raise_from(e, None)
File "<string>", line 3, in raise_from
File "/usr/local/lib/python3.6/site-packages/urllib3/connectionpool.py", line 440, in _make_request
httplib_response = conn.getresponse()
File "/usr/lib64/python3.6/http/client.py", line 1346, in getresponse
response.begin()
File "/usr/lib64/python3.6/http/client.py", line 307, in begin
version, status, reason = self._read_status()
File "/usr/lib64/python3.6/http/client.py", line 268, in _read_status
line = str(self.fp.readline(_MAXLINE + 1), "iso-8859-1")
File "/usr/lib64/python3.6/socket.py", line 586, in readinto
return self._sock.recv_into(b)
File "/usr/lib64/python3.6/ssl.py", line 971, in recv_into
`;
// create a data set with groups
var group_names = [];
var groups = new vis.DataSet();
for (let i = 0; i < nGroups; i++) {
group_names.push('GROUP_' + i);
groups.add({
id: group_names[i],
content: group_names[i]
});
}
// add meta group
groups.add({
id: -1,
content: ' '
});
// create a dataset with items
let items = new vis.DataSet();
for (let i = 0; i < nGroups; i++) {
let nSubGroups = randInt(1, maxSubGroups);
//console.log('group='+i+' nSubGroups='+nSubGroups);
let lastStartAdd = 0;
for (let sg = 0; sg < nSubGroups; sg++) {
let start_end = getStartEnd(lastStartAdd);
let start = now.clone().add(start_end['startAdd'], 'hours');
let end = now.clone().add(start_end['endAdd'], 'hours');
let itemID = 'G' + i + '_S' + sg + '_item';
let subgroupID = 'G' + i + '_S' + sg;
let subgroupOrder = sg;
let newItem = {
id: itemID,
group: group_names[i],
subgroup: subgroupID,
subgroupOrder: subgroupOrder,
content: 'ITEM_DU_' + 'G' + i + '_S' + sg,
start: start,
end: end,
title: 'ITEM_DU_' + 'G' + i + '_S' + sg
};
//console.log(group_names[i] + ', ' + 'S' + sg + ', ' +start_end['startAdd'] + ', ' + start_end['endAdd']);
items.add(newItem);
lastStartAdd = start_end['startAdd'];
// random crashes
if(Math.random() <= tcCrashProbability) {
let crashStart = now.clone().add(randInt(start_end['startAdd'], start_end['endAdd']), 'hours');
let newCrashItem = {
id: 'crash_' + itemID,
group: group_names[i],
subgroup: subgroupID,
subgroupOrder: subgroupOrder,
content: 'Crash',
start: crashStart,
type: 'box',
className: 'timeline-tc-crash',
title: '<pre>' + stackTrace + '</pre>'
};
items.add(newCrashItem);
}
}
}
// generate some meta events
for (let i = 0; i < metaEventCount; i++) {
let start = now.clone().add(Math.random() * 200, 'hours');
items.add({
id: 'M' + i,
group: -1,
content: 'Crash',
title: '<pre>' + stackTrace + '</pre>',
className: 'timeline-event-crash',
start: start,
type: 'box'
});
}
// create visualization
var container = document.getElementById('visualization');
var options = {
groupOrder: 'content',
stack: false,
stackSubgroups: true,
orientation: {
axis: 'both'
},
showCurrentTime: false
};
var timeline = new vis.Timeline(container);
timeline.setOptions(options);
timeline.setGroups(groups);
timeline.setItems(items);#visualization {
box-sizing: border-box;
width: 100%;
height: 300px;
}
.timeline-event-crash {
background-color: red !important;
border-color: darkred !important;
color: white !important;
font-family: monospace;
box-shadow: 0 0 10px gray;
}
.timeline-tc-crash {
color: red !important;
border-color: red !important;
background-color: #F4BBB5 !important;
}<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/seedrandom/2.3.10/seedrandom.min.js"></script>
<link href="https://visjs.github.io/vis-timeline/styles/vis-timeline-graph2d.min.css" rel="stylesheet" />
<script src="https://visjs.github.io/vis-timeline/standalone/umd/vis-timeline-graph2d.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.min.js"></script>
<html>
<head>
<title>Timeline</title>
</head>
<body>
<div id="visualization"></div>
</body>
</html>