synchronize map with mouse when dragging or zooming map

src/map/Map.Zoom.js

@@ -146,7 +146,9 @@ Map.include(/** @lends Map.prototype */{
         this._zoomLevel = nextZoom;
         this._calcMatrices();
         if (origin) {
-            this._setPrjCoordAtContainerPoint(this._startZoomCoord, origin);
+            const p = this._containerPointToPoint(origin);
+            const offset = p._sub(this._prjToPoint(this._getPrjCenter()));
+            this._setPrjCoordAtOffsetToCenter(this._startZoomCoord, offset);
         }
     },
 

src/map/Map.js

@@ -2078,6 +2078,22 @@ class Map extends Handlerable(Eventable(Renderable(Class))) {
         return this;
     }
 
+    _setPrjCoordAtOffsetToCenter(prjCoord, offset) {
+        const pcenter = this._pointToPrj(this._prjToPoint(prjCoord).sub(offset));
+        this._setPrjCenter(pcenter);
+        return this;
+    }
+
+    _queryTerrainAtPoint(p) {
+        const group = this.getLayers(layer => {
+            return layer.queryTerrainAtPoint;
+        })[0];
+        if (group && group.getTerrainLayer()) {
+            return group.queryTerrainAtPoint(p);
+        }
+        return null;
+    }
+
     _verifyExtent(prjCenter) {
         if (!prjCenter) {
             return false;

src/map/handler/Map.Drag.js

@@ -110,7 +110,7 @@ class MapDragHandler extends Handler {
         const map = this.target;
         map.onMoveStart(param);
         const p = getEventContainerPoint(map._getActualEvent(param.domEvent), map.getContainer());
-        this.startPrjCoord = map._containerPointToPrj(p);
+        this.startPrjCoord = this._containerPointToPrj(p);
     }
 
     _moving(param) {
@@ -119,10 +119,23 @@ class MapDragHandler extends Handler {
         }
         const map = this.target;
         const p = getEventContainerPoint(map._getActualEvent(param.domEvent), map.getContainer());
-        map._setPrjCoordAtContainerPoint(this.startPrjCoord, p);
+        const point = map._prjToPoint(this._containerPointToPrj(p));
+        const offset = point._sub(map._prjToPoint(map._getPrjCenter()));
+        map._setPrjCoordAtOffsetToCenter(this.startPrjCoord, offset);
         map.onMoving(param);
     }
 
+    _containerPointToPrj(p) {
+        const map = this.target;
+        const queryCoord = map._queryTerrainAtPoint(p);
+        if (queryCoord) {
+            const prjCoord = map.getProjection().project(queryCoord);
+            prjCoord.z = queryCoord.z;
+            return prjCoord;
+        }
+        return map._containerPointToPrj(p);
+    }
+
     _moveEnd(param) {
         if (!this.startDragTime) {
             return;

test/map/MapDragSpec.js

@@ -187,4 +187,25 @@ describe('Map.Drag', function () {
         expect(center2.toArray()).not.to.be.eql(center.toArray());
         expect(map.isMoving()).not.to.be.ok();
     });
+
+    it('synchronize with mouse when dragging map', (done) => {
+        map.setPitch(45);
+        //vlayer用于模拟鼠标的位置和高度
+        const vlayer = new maptalks.VectorLayer('v').addTo(map);
+        vlayer.queryTerrainAtPoint = function(containerPoint) {
+            const coord = map.containerPointToCoordinate(containerPoint);
+            return new maptalks.Coordinate(coord.x, coord.y - 0.2, 100);
+        };
+        vlayer.getTerrainLayer = function() {
+            return true;
+        }
+        map.on('moveend', function () {
+            expect(map.isMoving()).not.to.be.ok();
+            const center = map.getCenter();
+            expect(center.x).to.eql(118.84493355);
+            expect(center.y).to.eql(32.04882672);
+            done();
+        });
+        dragMap(100);
+    });
 });

test/map/MapScrollZoomSpec.js

@@ -5,10 +5,12 @@ describe('Map.ScrollZoom', function () {
     var map;
     var center = new maptalks.Coordinate(118.846825, 32.046534);
     var delay;
-    function scrollMap(delta) {
+    function scrollMap(delta, clientX, clientY) {
         happen.once(container, {
             type: 'wheel',
-            detail: delta
+            detail: delta,
+            clientX: clientX || map.width / 2,
+            clientY: clientY || map.height / 2
         });
     }
 
@@ -52,6 +54,26 @@ describe('Map.ScrollZoom', function () {
             map.on('zoomend', onZoomEnd);
             scrollMap(-100);
         });
+
+        it('synchronize with mouse when scroll zoom map', (done) => {
+            map.setPitch(45);
+            //vlayer用于模拟鼠标的位置和高度
+            const vlayer = new maptalks.VectorLayer('v').addTo(map);
+            vlayer.queryTerrainAtPoint = function(containerPoint) {
+                const coord = map.containerPointToCoordinate(containerPoint);
+                return new maptalks.Coordinate(coord.x, coord.y - 0.2, 100);
+            };
+            vlayer.getTerrainLayer = function() {
+                return true;
+            }
+            map.on('zoomend', function () {
+                const center = map.getCenter();
+                expect(center.x.toFixed(4)).to.eql(118.8474);
+                expect(center.y.toFixed(4)).to.eql(32.0460);
+                done();
+            });
+            scrollMap(100, 10, 10);
+        });
     });
 
     describe('scrollZoom can be disable', function () {