在OpenLayers中为每个组件绘制具有不同样式的MultiPolygon

2 回答

• 2

  据我所知，要获得此功能，您需要使用自己的类扩展类 .

  首先创建OpenLayers.Feature.Vector的扩展，将其命名为YourApp.Feature.MultiVector . 您可以通过查看OpenLayers代码来查看有关如何扩展类的示例 . 该类应该接受样式数组和multiPolygon . 它应该有一个方法，它将返回一个OpenLayers.Feature.Vectors列表，每个都有自己的样式 .

  第二步创建OpenLayers.Layer.Vector的扩展，将其命名为YourApp.Layer.VectorSupportingMultiStyledFeatures . 您需要覆盖“drawFeature”方法 . 在drawFeature方法测试中，查看特征的类型是否为MultiVector . 如果是，则遍历MultiVector中的每个要素并调用renderer.drawFeature（feature） . 否则调用super.drawFeature方法 .

  所以你调用它的代码看起来像这样：

  var multiPol = new YourApp.Feature.MultiVector(
      new OpenLayers.Geometry.MultiPolygon([polygonGeometry1,polygonGeometry2]),
      [style1,style2,style3,style4]);
  
  var layer = new YourApp.Layer.VectorSupportingMultiStyledFeatures("polygonLayer");
  layer.addFeatures([multiPol]);
  

  回复于 2024-05-03T17:27:20+08:00
• 1

  Jon Snyder提出的解决方案为我们提供了一个总体思路，但最终没有完全发挥作用（特别是基于OpenLayers 2.1x，此任务不需要扩展 OpenLayers.Layer.Vector ） .

  我们创建了一个类 YourApp.Handler.EndPointsPath （扩展 OpenLayers.Handler.Path ），其中函数 geometryClone() 返回一个类型为 YourApp.Geometry.EndPointsPath 的新几何 .

  然后，我们修补 OpenLayers.Renderer.Elements 中的函数 drawGeometry() 来绘制这个新几何：

  OpenLayers.Util.extend(OpenLayers.Renderer.Elements.prototype, {
  
    drawGeometry: function (geometry, style, featureId) {
      var cl = geometry.CLASS_NAME;
  
      var rendered = true,
        i, len;
      if ((cl === "OpenLayers.Geometry.Collection") ||
        (cl === "OpenLayers.Geometry.MultiPoint") ||
        (cl === "OpenLayers.Geometry.MultiLineString") ||
        (cl === "OpenLayers.Geometry.MultiPolygon") ||
        (cl === "YourApp.Geometry.EndPointsPath")) {
        // Iterate over all Geometry components and draw each individually
        for (i = 0, len = geometry.components.length; i < len; i++) {
          // Is there a style for each of the components?
          if (OpenLayers.Util.isArray(style)) {
            // Draw Geometry with own style
            rendered = this.drawGeometry(geometry.components[i], style[i], featureId) && rendered;
          } else {
            // Draw Geometry with common style 
            rendered = this.drawGeometry(geometry.components[i], style, featureId) && rendered;
          }
        }
        return rendered;
      }
      // (...standard code...)
    },
  
    eraseGeometry: function (geometry, featureId) {
      var cl = geometry.CLASS_NAME,
        i, len;
      if ((cl === "OpenLayers.Geometry.MultiPoint") ||
        (cl === "OpenLayers.Geometry.MultiLineString") ||
        (cl === "OpenLayers.Geometry.MultiPolygon") ||
        (cl === "YourApp.Geometry.EndPointsPath") ||
        (cl === "OpenLayers.Geometry.Collection")) {
        for (i = 0, len = geometry.components.length; i < len; i++) {
          this.eraseGeometry(geometry.components[i], featureId);
        }
        // (...standard code...)
      }
    }
  });
  

  回复于 2024-05-03T17:27:20+08:00