如何在OpenLayers-3上将SVG图像用作图层

Question

如何通过OpenLayers-3将SVG图像用作图层(因此不能用作地图标记

在使用任何ol.source.Vector和ol.format.Feature实例时，我无法获得我的SVG图像的任何输出。

小示例：

var mapLayer = new ol.layer.Vector({
    source: new ol.source.Vector({
        url: 'image.svg',
        format: new ol.format.Feature() // http://openlayers.org/en/v3.12.1/apidoc/ol.format.Feature.html
    }),
}); 

我可以在使用ImageStatic层时获得输出，但这里使用/generates(？)一个静态的图像，所以SVG的优势消失了。

示例：

// Not sure if I need this for SVG, but is is required for an image
var extent = [0, 0, 1000, 1000]; // random image size
var projection = new ol.proj.Projection({
    code: 'test',
    units: 'pixels',
    extent: extent
});

var mapLayer = new ol.layer.Image({
    source: new ol.source.ImageStatic({
        url: 'image.svg',
        projection: projection,
        imageExtent: extent
    })
});

我已经尝试过将Content-type:设置为image/svg+xml，但这对我一点帮助都没有。

所以，再说一次:我如何(如果可能)在OpenLayers-3中使用SVG图像a层？

Answer 1

不能将ol.source.Vector与svg文件一起使用，但OL3可以将svg文件显示为图像。

图像在缩放时仍保持清晰。

我修改了官方的static image example，并将png文件替换为svg文件。请参阅下面的runnable示例。

​

var extent = [0, 0, 512, 512];
var projection = new ol.proj.Projection({
  code: 'static-image',
  units: 'pixels',
  extent: extent
});

var map = new ol.Map({
  layers: [
    new ol.layer.Image({
      source: new ol.source.ImageStatic({
        url: 'https://upload.wikimedia.org/wikipedia/commons/f/fd/Ghostscript_Tiger.svg',
        projection: projection,
        imageExtent: extent
      })
    })
  ],
  target: 'map',
  view: new ol.View({
    projection: projection,
    center: ol.extent.getCenter(extent),
    zoom: 0
  })
});

<script src="https://cdn.rawgit.com/openlayers/openlayers.github.io/master/en/v5.3.0/build/ol.js"></script>
<link href="https://cdn.rawgit.com/openlayers/openlayers.github.io/master/en/v5.3.0/css/ol.css" rel="stylesheet"/>
<div id="map" class="map"></div>

​

Answer 2

目前，2018是开放式第4层的示例

​

var svgComment = '<svg width="160" height="160" version="1.1" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 160 160" viewPort="0 0 160 160" class="svgClass">'
    + '<circle cx="30" cy="30" r="10" stroke="rgb(0, 191, 255)" stroke-width="1" fill="none" opacity="0.8">'
    + '<animate attributeType="CSS" attributeName="stroke-width" from="1" to="30" dur="0.5s" begin="0s" repeatCount="indefinite" />'
    + '<animate attributeType="CSS" attributeName="opacity" from="0.8" to="0.2" dur="0.5s" begin="0s" repeatCount="indefinite" />'
    + '</circle>'
    + '<circle cx="30" cy="30" r="10" fill="rgba(0,0,0,0.8)">'
    + '</circle>'
    + '</svg>';


//Test SVG
//var img = document.createElement('img');
//img.src=src;
//document.body.append(img);

 var commentStyle =  new ol.style.Style({
    image: new ol.style.Icon({
      src: 'data:image/svg+xml;charset=utf-8,' + encodeURIComponent(svgComment)
    })
  });

var vectorSource = new ol.source.Vector({
  features: [
      new ol.Feature({
        geometry: new ol.geom.Point([0, 0])
      }) 
  ]
});

var vectorLayer = new ol.layer.Vector({
  name: 'Comments',
  style: commentStyle,
  source: vectorSource
});

//display the map
var rasterLayer = new ol.layer.Tile({
  source: new ol.source.TileJSON({
    url: 'https://api.tiles.mapbox.com/v3/mapbox.geography-class.json?secure',
    crossOrigin: ''
  })
});

var map = new ol.Map({
  layers: [rasterLayer, vectorLayer],
  target: document.getElementById('map'),
  view: new ol.View({
    center: [0, 0],
    zoom: 3
  })
});

<script src="https://openlayers.org/en/v4.6.4/build/ol.js"></script>
<div id="map" class="map"></div>

​

请参阅原文：

https://stackoverflow.com/a/48232790/2797243

Answer 3

@Alvin Lindstam的答案几乎就在那里，但在Chrome (或IE)上没有显示完整的图像。因为SVG没有固定的大小，所以需要在imageLoadFunction中设置宽度和高度

​

var extent = [0, 0, 512, 512];
var projection = new ol.proj.Projection({
  code: 'static-image',
  units: 'pixels',
  extent: extent
});

var map = new ol.Map({
  layers: [
    new ol.layer.Image({
      source: new ol.source.ImageStatic({
        url: 'https://upload.wikimedia.org/wikipedia/commons/f/fd/Ghostscript_Tiger.svg',
        projection: projection,
        imageExtent: extent,
        imageLoadFunction: function (image, src) {
           image.getImage().src = src;
           image.getImage().width = ol.extent.getWidth(extent);
           image.getImage().height = ol.extent.getHeight(extent);
        }
      })
    })
  ],
  target: 'map',
  view: new ol.View({
    projection: projection,
    center: ol.extent.getCenter(extent),
    zoom: 0
  })
});

<script src="https://cdn.rawgit.com/openlayers/openlayers.github.io/master/en/v5.3.0/build/ol.js"></script>
<link href="https://cdn.rawgit.com/openlayers/openlayers.github.io/master/en/v5.3.0/css/ol.css" rel="stylesheet"/>
<div id="map" class="map"></div>

​