当我用'line-dasharray'属性绘制虚线时，它的行为很奇怪-缩放时线和间隙的长度会改变。参见示例。问题：如何绘制具有恒定线和间隙长度且在放大/缩小时不会改变的虚线？
//这个愚蠢的机器人说我的帖子主要是代码。不知道里面有什么问题
//但必须添加一些愚蠢的文本行
<!DOCTYPE html>
<html>
<head>
<meta charset='utf-8' />
<title>Add a GeoJSON line</title>
<meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no' />
<script src='https://api.tiles.mapbox.com/mapbox-gl-js/v0.44.1/mapbox-gl.js'></script>
<link href='https://api.tiles.mapbox.com/mapbox-gl-js/v0.44.1/mapbox-gl.css' rel='stylesheet' />
<style>
body { margin:0; padding:0; }
#map { position:absolute; top:0; bottom:0; width:100%; }
</style>
</head>
<body>
<div id='map'></div>
<script>
mapboxgl.accessToken = 'pk.eyJ1IjoibHVjYXN3b2oiLCJhIjoiY2l5Nmg4cWU1MDA0ejMzcDJtNHJmZzJkcyJ9.WhcEdTYQH6sSw2pm0RSP9Q';
var map = new mapboxgl.Map({
container: 'map',
style: 'mapbox://styles/mapbox/streets-v9',
center: [-122.486052, 37.830348],
zoom: 15
});
map.on('load', function () {
map.addLayer({
"id": "route",
"type": "line",
"source": {
"type": "geojson",
"data": {
"type": "Feature",
"properties": {},
"geometry": {
"type": "LineString",
"coordinates": [
[-122.48369693756104, 37.83381888486939],
[-122.48348236083984, 37.83317489144141],
[-122.48339653015138, 37.83270036637107],
[-122.48356819152832, 37.832056363179625],
[-122.48404026031496, 37.83114119107971],
[-122.48404026031496, 37.83049717427869],
[-122.48348236083984, 37.829920943955045],
[-122.48356819152832, 37.82954808664175],
[-122.48507022857666, 37.82944639795659],
[-122.48610019683838, 37.82880236636284],
[-122.48695850372314, 37.82931081282506],
[-122.48700141906738, 37.83080223556934],
[-122.48751640319824, 37.83168351665737],
[-122.48803138732912, 37.832158048267786],
[-122.48888969421387, 37.83297152392784],
[-122.48987674713133, 37.83263257682617],
[-122.49043464660643, 37.832937629287755],
[-122.49125003814696, 37.832429207817725],
[-122.49163627624512, 37.832564787218985],
[-122.49223709106445, 37.83337825839438],
[-122.49378204345702, 37.83368330777276]
]
}
}
},
"paint": {
"line-color": "#888",
"line-width": 8,
"line-dasharray": [5, 5]
}
});
});
</script>
</body>
</html>好吧，我发现了一些使它变得更好的东西，但是由于虚线随着比例的变化而不断变化，它仍然不是完美的。
答案的一部分是，线之间的间隙以线宽单位而不是像素指定。当线宽恒定（以像素为单位）且不取决于缩放比例时，缩放级别更改时，线的大小（例如，以米为单位）将变得更大或更小。这也会导致线之间的间隙也发生变化。在这里，您可以找到有关如何制作可变宽度线的说明，该宽度将取决于缩放级别并保持其相对大小。
这是我在示例中采用的方法（它变得更好了，但是当我放大/缩小时仍然会改变行）：
<!DOCTYPE html>
<html>
<head>
<meta charset='utf-8' />
<title>Add a GeoJSON line</title>
<meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no' />
<script src='https://api.tiles.mapbox.com/mapbox-gl-js/v0.44.1/mapbox-gl.js'></script>
<link href='https://api.tiles.mapbox.com/mapbox-gl-js/v0.44.1/mapbox-gl.css' rel='stylesheet' />
<style>
body { margin:0; padding:0; }
#map { position:absolute; top:0; bottom:0; width:100%; }
</style>
</head>
<body>
<div id='map'></div>
<script>
mapboxgl.accessToken = 'pk.eyJ1IjoibHVjYXN3b2oiLCJhIjoiY2l5Nmg4cWU1MDA0ejMzcDJtNHJmZzJkcyJ9.WhcEdTYQH6sSw2pm0RSP9Q';
var map = new mapboxgl.Map({
container: 'map',
style: 'mapbox://styles/mapbox/streets-v9',
center: [-122.486052, 37.830348],
zoom: 15
});
map.on('load', function () {
let baseWidth = 5;
let baseZoom = 15;
map.addLayer({
"id": "route",
"type": "line",
"source": {
"type": "geojson",
"data": {
"type": "Feature",
"properties": {},
"geometry": {
"type": "LineString",
"coordinates": [
[-122.48369693756104, 37.83381888486939],
[-122.48348236083984, 37.83317489144141],
[-122.48339653015138, 37.83270036637107],
[-122.48356819152832, 37.832056363179625],
[-122.48404026031496, 37.83114119107971],
[-122.48404026031496, 37.83049717427869],
[-122.48348236083984, 37.829920943955045],
[-122.48356819152832, 37.82954808664175],
[-122.48507022857666, 37.82944639795659],
[-122.48610019683838, 37.82880236636284],
[-122.48695850372314, 37.82931081282506],
[-122.48700141906738, 37.83080223556934],
[-122.48751640319824, 37.83168351665737],
[-122.48803138732912, 37.832158048267786],
[-122.48888969421387, 37.83297152392784],
[-122.48987674713133, 37.83263257682617],
[-122.49043464660643, 37.832937629287755],
[-122.49125003814696, 37.832429207817725],
[-122.49163627624512, 37.832564787218985],
[-122.49223709106445, 37.83337825839438],
[-122.49378204345702, 37.83368330777276]
]
}
}
},
"paint": {
"line-color": "#888",
"line-width":
{
'type': 'exponential',
'base': 2,
'stops': [
[0, baseWidth * Math.pow(2, (0 - baseZoom))],
[22, baseWidth * Math.pow(2, (22 - baseZoom))]
]
},
"line-dasharray": [5, 5]
}
});
});
</script>
</body>
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