添加场景缩放控制

src/core/widget/ZoomController.js

  */
 
 import Widget from './Widget'
+import { DomUtil } from '../utils'
+import Icon from '../icon'
+
+const { Cesium } = DC.Namespace
 
 class ZoomController extends Widget {
   constructor() {
     super()
+    this._wrapper = DomUtil.create('div', 'dc-zoom-controller')
+    this._zoomInEl = undefined
+    this._zoomOutEl = undefined
+    this._refreshEl = undefined
+  }
+
+  /**
+   *
+   * @param scene
+   * @returns {Cartesian3}
+   * @private
+   */
+  _getCameraFocus(scene) {
+    const ray = new Cesium.Ray(
+      scene.camera.positionWC,
+      scene.camera.directionWC
+    )
+    const intersections = Cesium.IntersectionTests.rayEllipsoid(
+      ray,
+      Cesium.Ellipsoid.WGS84
+    )
+    if (intersections) {
+      return Cesium.Ray.getPoint(ray, intersections.start)
+    }
+    // Camera direction is not pointing at the globe, so use the ellipsoid horizon point as
+    // the focal point.
+    return Cesium.IntersectionTests.grazingAltitudeLocation(
+      ray,
+      Cesium.Ellipsoid.WGS84
+    )
+  }
+
+  /**
+   *
+   * @param camera
+   * @param focus
+   * @param scalar
+   * @returns {Cartesian3}
+   * @private
+   */
+  _getCameraPosition(camera, focus, scalar) {
+    const cartesian3Scratch = new Cesium.Cartesian3()
+    let direction = Cesium.Cartesian3.subtract(
+      focus,
+      camera.position,
+      cartesian3Scratch
+    )
+    let movementVector = Cesium.Cartesian3.multiplyByScalar(
+      direction,
+      scalar,
+      cartesian3Scratch
+    )
+    return Cesium.Cartesian3.add(
+      camera.position,
+      movementVector,
+      cartesian3Scratch
+    )
+  }
+
+  /**
+   *
+   * @returns {boolean}
+   * @private
+   */
+  _zoomIn() {
+    let scene = this._viewer.scene
+    let camera = scene.camera
+    let sscc = scene.screenSpaceCameraController
+    if (
+      scene.mode === Cesium.SceneMode.MORPHING ||
+      !sscc.enableInputs ||
+      scene.mode === Cesium.SceneMode.COLUMBUS_VIEW
+    ) {
+      return true
+    } else if (scene.mode === Cesium.SceneMode.SCENE2D) {
+      camera.zoomIn(camera.positionCartographic.height * 0.5)
+    } else if (scene.mode === Cesium.SceneMode.SCENE3D) {
+      let focus = this._getCameraFocus(scene)
+      let cameraPosition = this._getCameraPosition(camera, focus, 1 / 2)
+      camera.flyTo({
+        destination: cameraPosition,
+        orientation: {
+          heading: camera.heading,
+          pitch: camera.pitch,
+          roll: camera.roll
+        },
+        duration: 0.5,
+        convert: false
+      })
+    }
+  }
+
+  /**
+   *
+   * @private
+   */
+  _refresh() {
+    this._viewer.camera.flyHome(1.5)
+  }
+
+  /**
+   *
+   * @returns {boolean}
+   * @private
+   */
+  _zoomOut() {
+    let scene = this._viewer.scene
+    let camera = scene.camera
+    let sscc = scene.screenSpaceCameraController
+    if (
+      scene.mode === Cesium.SceneMode.MORPHING ||
+      !sscc.enableInputs ||
+      scene.mode === Cesium.SceneMode.COLUMBUS_VIEW
+    ) {
+      return true
+    } else if (scene.mode === Cesium.SceneMode.SCENE2D) {
+      camera.zoomOut(camera.positionCartographic.height)
+    } else if (scene.mode === Cesium.SceneMode.SCENE3D) {
+      let focus = this._getCameraFocus(scene)
+      let cameraPosition = this._getCameraPosition(camera, focus, -1)
+      camera.flyTo({
+        destination: cameraPosition,
+        orientation: {
+          heading: camera.heading,
+          pitch: camera.pitch,
+          roll: camera.roll
+        },
+        duration: 0.5,
+        convert: false
+      })
+    }
+  }
+
+  /**
+   *
+   * @private
+   */
+  _installHook() {
+    Object.defineProperty(this._viewer, 'zoomController', {
+      value: this,
+      writable: false
+    })
+  }
+
+  /**
+   *
+   * @private
+   */
+  _mountContent() {
+    this._zoomInEl = DomUtil.parseDom(Icon.increase, true, 'zoom-in')
+    this._refreshEl = DomUtil.parseDom(Icon.refresh, true, 'refresh')
+    this._zoomOutEl = DomUtil.parseDom(Icon.decrease, true, 'zoom-out')
+    this._wrapper.appendChild(this._zoomInEl)
+    this._wrapper.appendChild(this._refreshEl)
+    this._wrapper.appendChild(this._zoomOutEl)
+    let self = this
+    this._zoomInEl.onclick = e => {
+      self._zoomIn()
+    }
+    this._refreshEl.onclick = e => {
+      self._refresh()
+    }
+    this._zoomOutEl.onclick = e => {
+      self._zoomOut()
+    }
+    this._ready = true
   }
 }
+
+export default ZoomController

src/core/widget/index.js

 import HawkeyeMap from './HawkeyeMap'
 import Compass from './Compass'
 import DistanceLegend from './DistanceLegend'
+import ZoomController from './ZoomController'
 
 const Widgets = {
   attribution: new Attribution(),
   locationBar: new LocationBar(),
   hawkeyeMap: new HawkeyeMap(),
   compass: new Compass(),
-  distanceLegend: new DistanceLegend()
+  distanceLegend: new DistanceLegend(),
+  zoomController: new ZoomController()
 }
 
 export default Widgets

src/themes/index.js

 import './compass.scss'
 import './locationbar.scss'
 import './distancelegend.scss'
+import './zoom-controller.scss'

src/themes/zoom-controller.scss

+.dc-zoom-controller{
+  position: absolute;
+  top: 90px;
+  right: 36.5px;
+  pointer-events: auto;
+  user-select: none;
+  background: #3f4854;
+  border-radius: 100px;
+  border: solid 1px rgba(255,255,255,0.2);
+  text-align: center;
+  box-sizing: border-box;
+  line-height: 1.2rem;
+  width: 24px;
+  height: 60px;
+  .zoom-in ,.refresh,.zoom-out{
+    cursor: pointer;
+    svg{
+      width: 10px;
+      height: 10px;
+      fill: #fff;
+    }
+  }
+}