Merge pull request #3010 from ahocevar/style-geometry

Allow styles to override feature geometries

src/ol/render/canvas/canvasimmediate.js

@@ -477,7 +477,7 @@ ol.render.canvas.Immediate.prototype.drawCircleGeometry =
  * @api
  */
 ol.render.canvas.Immediate.prototype.drawFeature = function(feature, style) {
-  var geometry = feature.getGeometry();
+  var geometry = style.getGeometryFunction()(feature);
   if (!goog.isDefAndNotNull(geometry) ||
       !ol.extent.intersects(this.extent_, geometry.getExtent())) {
     return;

src/ol/render/vector.js

@@ -123,7 +123,7 @@ ol.renderer.vector.renderFeature = function(
  */
 ol.renderer.vector.renderFeature_ = function(
     replayGroup, feature, style, squaredTolerance) {
-  var geometry = feature.getGeometry();
+  var geometry = style.getGeometryFunction()(feature);
   if (!goog.isDefAndNotNull(geometry)) {
     return;
   }

src/ol/render/webgl/webglimmediate.js

@@ -118,7 +118,7 @@ ol.render.webgl.Immediate.prototype.drawCircleGeometry =
  * @api
  */
 ol.render.webgl.Immediate.prototype.drawFeature = function(feature, style) {
-  var geometry = feature.getGeometry();
+  var geometry = style.getGeometryFunction()(feature);
   if (!goog.isDefAndNotNull(geometry) ||
       !ol.extent.intersects(this.extent_, geometry.getExtent())) {
     return;

src/ol/style/style.js

@@ -1,7 +1,9 @@
 goog.provide('ol.style.Style');
+goog.provide('ol.style.defaultGeometryFunction');
 
 goog.require('goog.asserts');
 goog.require('goog.functions');
+goog.require('ol.geom.Geometry');
 goog.require('ol.geom.GeometryType');
 goog.require('ol.style.Circle');
 goog.require('ol.style.Fill');
@@ -24,6 +26,22 @@ ol.style.Style = function(opt_options) {
 
   var options = goog.isDef(opt_options) ? opt_options : {};
 
+  /**
+   * @private
+   * @type {string|ol.geom.Geometry|ol.style.GeometryFunction}
+   */
+  this.geometry_ = null;
+
+  /**
+   * @private
+   * @type {!ol.style.GeometryFunction}
+   */
+  this.geometryFunction_ = ol.style.defaultGeometryFunction;
+
+  if (goog.isDef(options.geometry)) {
+    this.setGeometry(options.geometry);
+  }
+
   /**
    * @private
    * @type {ol.style.Fill}
@@ -57,6 +75,27 @@ ol.style.Style = function(opt_options) {
 };
 
 
+/**
+ * @return {string|ol.geom.Geometry|ol.style.GeometryFunction}
+ * Feature property or geometry or function that returns the geometry that will
+ * be rendered with this style.
+ * @api
+ */
+ol.style.Style.prototype.getGeometry = function() {
+  return this.geometry_;
+};
+
+
+/**
+ * @return {!ol.style.GeometryFunction} Function that is called with a feature
+ * and returns the geometry to render instead of the feature's geometry.
+ * @api
+ */
+ol.style.Style.prototype.getGeometryFunction = function() {
+  return this.geometryFunction_;
+};
+
+
 /**
  * @return {ol.style.Fill} Fill style.
  * @api
@@ -102,6 +141,37 @@ ol.style.Style.prototype.getZIndex = function() {
 };
 
 
+/**
+ * Set a geometry that is rendered instead of the feature's geometry.
+ *
+ * @param {string|ol.geom.Geometry|ol.style.GeometryFunction} geometry
+ *     Feature property or geometry or function returning a geometry to render
+ *     for this style.
+ * @api
+ */
+ol.style.Style.prototype.setGeometry = function(geometry) {
+  if (goog.isFunction(geometry)) {
+    this.geometryFunction_ = geometry;
+  } else if (goog.isString(geometry)) {
+    this.geometryFunction_ = function(feature) {
+      var result = feature.get(geometry);
+      if (goog.isDefAndNotNull(result)) {
+        goog.asserts.assertInstanceof(result, ol.geom.Geometry);
+      }
+      return result;
+    };
+  } else if (goog.isNull(geometry)) {
+    this.geometryFunction_ = ol.style.defaultGeometryFunction;
+  } else if (goog.isDef(geometry)) {
+    goog.asserts.assertInstanceof(geometry, ol.geom.Geometry);
+    this.geometryFunction_ = function() {
+      return geometry;
+    };
+  }
+  this.geometry_ = geometry;
+};
+
+
 /**
  * Set the zIndex.
  *
@@ -264,3 +334,24 @@ ol.style.createDefaultEditingStyles = function() {
 
   return styles;
 };
+
+
+/**
+ * A function that takes an {@link ol.Feature} as argument and returns an
+ * {@link ol.geom.Geometry} that will be rendered and styled for the feature.
+ *
+ * @typedef {function(ol.Feature): (ol.geom.Geometry|undefined)}
+ * @api
+ */
+ol.style.GeometryFunction;
+
+
+/**
+ * Function that is called with a feature and returns its default geometry.
+ * @param {ol.Feature} feature Feature to get the geometry for.
+ * @return {ol.geom.Geometry|undefined} Geometry to render.
+ */
+ol.style.defaultGeometryFunction = function(feature) {
+  goog.asserts.assert(!goog.isNull(feature));
+  return feature.getGeometry();
+};