fix center point calculation error in Map.fitExtent

src/map/Map.ts

@@ -20,7 +20,7 @@ import Handlerable from '../handler/Handlerable';
 import Point from '../geo/Point';
 import Size from '../geo/Size';
 import PointExtent from '../geo/PointExtent';
-import Extent from '../geo/Extent';
+import Extent, { ExtentLike } from '../geo/Extent';
 import Coordinate from '../geo/Coordinate';
 import Layer from '../layer/Layer';
 import Renderable from '../renderer/Renderable';
@@ -1152,7 +1152,7 @@ export class Map extends Handlerable(Eventable(Renderable(Class))) {
 
     /**
      * Set the map to be fit for the given extent with the max zoom level possible.
-     * @param  {Extent} extent - extent
+     * @param  {ExtentLike} extent - extent
      * @param  {Number} zoomOffset - zoom offset
      * @param  {Object} [options={}] - options
      * @param  {Object} [options.animation]
@@ -1167,14 +1167,15 @@ export class Map extends Handlerable(Eventable(Renderable(Class))) {
      * @param  {Function} step - step function for animation
      * @return {Map | player} - this
      */
-    fitExtent(extent: Extent, zoomOffset?: number, options?: MapFitType, step?: (frame) => void) {
+    fitExtent(extent: ExtentLike, zoomOffset?: number, options?: MapFitType, step?: (frame) => void) {
         options = (options || {} as any);
         if (!extent) {
             return this;
         }
-        extent = new Extent(extent, this.getProjection());
-        const zoom = this.getFitZoom(extent, options.isFraction || false, options) + (zoomOffset || 0);
-        let center = extent.getCenter();
+        const syncExtent = new Extent(extent);
+        const zoom = this.getFitZoom(syncExtent, options.isFraction || false, options) + (zoomOffset || 0);
+        const containerExtent = syncExtent.convertTo(p => this.coordToPoint(p));
+        let center = this.pointToCoord(containerExtent.getCenter() as Point);
         if (this._getPaddingSize(options)) {
             center = this._getCenterByPadding(center, zoom, options);
         }

test/map/MapSpec.js

@@ -366,6 +366,18 @@ describe('Map.Spec', function () {
             map.fitExtent(extent.toJSON());
         });
 
+        it('fit to china extent', function (done) {
+            const chinaExtent = [73.499013,3.397894,135.087377,53.561308];
+            map.fitExtent(chinaExtent, 0, { 'animation': false });
+            const [lon, lat] = map.getCenter().toArray();
+            const lonDiff = Math.abs(lon - 104.293195);
+            const latDiff = Math.abs(lat - 31.76872613);
+            const delta = Math.pow(10,-10);
+            expect(lonDiff).to.be.below(delta);
+            expect(latDiff).to.be.below(delta);
+            done();
+        });
+
         it('update zoom', function (done) {
             map.once('zoomend', function () {
                 map.once('zoomend', function () {