From 0c3daa95a4d69338a1493921cd333b8bec1b153e Mon Sep 17 00:00:00 2001
From: Vladimir Agafonkin <agafonkin@gmail.com>
Date: Tue, 18 Apr 2017 19:05:10 +0300
Subject: [PATCH] anti-meridian crossing for easeTo; do not wrap if maxBounds
 set (#4602)

- Enable anti-meridian crossing for `easeTo`-based methods for
consistency with `flyTo`.
- Fix #2521 by disabling anti-meridian crossing if `maxBounds` is set.
---
 src/ui/camera.js            | 25 ++++++++++++++----------
 test/unit/ui/camera.test.js | 38 +++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 10 deletions(-)

diff --git a/src/ui/camera.js b/src/ui/camera.js
index a7058207ee2..716d1b62fdf 100644
--- a/src/ui/camera.js
+++ b/src/ui/camera.js
@@ -512,6 +512,8 @@ class Camera extends Evented {
         const pointAtOffset = tr.centerPoint.add(Point.convert(options.offset));
         const locationAtOffset = tr.pointLocation(pointAtOffset);
         const center = LngLat.convert(options.center || locationAtOffset);
+        this._normalizeCenter(center);
+
         const from = tr.project(locationAtOffset);
         const delta = tr.project(center).sub(from);
         const finalScale = tr.zoomScale(zoom - startZoom);
@@ -695,16 +697,7 @@ class Camera extends Evented {
         const pointAtOffset = tr.centerPoint.add(Point.convert(options.offset));
         const locationAtOffset = tr.pointLocation(pointAtOffset);
         const center = LngLat.convert(options.center || locationAtOffset);
-
-        // If a path crossing the antimeridian would be shorter, extend the final coordinate so that
-        // interpolating between the two endpoints will cross it.
-        if (tr.renderWorldCopies && Math.abs(tr.center.lng) + Math.abs(center.lng) > 180) {
-            if (tr.center.lng > 0 && center.lng < 0) {
-                center.lng += 360;
-            } else if (tr.center.lng < 0 && center.lng > 0) {
-                center.lng -= 360;
-            }
-        }
+        this._normalizeCenter(center);
 
         const from = tr.project(locationAtOffset);
         const delta = tr.project(center).sub(from);
@@ -868,6 +861,18 @@ class Camera extends Evented {
         return bearing;
     }
 
+    // If a path crossing the antimeridian would be shorter, extend the final coordinate so that
+    // interpolating between the two endpoints will cross it.
+    _normalizeCenter(center) {
+        const tr = this.transform;
+        if (!tr.renderWorldCopies || tr.lngRange) return;
+
+        const delta = center.lng - tr.center.lng;
+        center.lng +=
+            delta > 180 ? -360 :
+            delta < -180 ? 360 : 0;
+    }
+
     // only used on mouse-wheel zoom to smooth out animation
     _smoothOutEasing(duration) {
         let easing = util.ease;
diff --git a/test/unit/ui/camera.test.js b/test/unit/ui/camera.test.js
index 0b0d51c3fac..08aafe7c40d 100644
--- a/test/unit/ui/camera.test.js
+++ b/test/unit/ui/camera.test.js
@@ -727,6 +727,44 @@ test('camera', (t) => {
             });
         });
 
+        t.test('pans eastward across the antimeridian', (t) => {
+            const camera = createCamera();
+            camera.setCenter([170, 0]);
+            let crossedAntimeridian;
+
+            camera.on('move', () => {
+                if (camera.getCenter().lng > 170) {
+                    crossedAntimeridian = true;
+                }
+            });
+
+            camera.on('moveend', () => {
+                t.ok(crossedAntimeridian);
+                t.end();
+            });
+
+            camera.easeTo({ center: [-170, 0], duration: 10 });
+        });
+
+        t.test('pans westward across the antimeridian', (t) => {
+            const camera = createCamera();
+            camera.setCenter([-170, 0]);
+            let crossedAntimeridian;
+
+            camera.on('move', () => {
+                if (camera.getCenter().lng < -170) {
+                    crossedAntimeridian = true;
+                }
+            });
+
+            camera.on('moveend', () => {
+                t.ok(crossedAntimeridian);
+                t.end();
+            });
+
+            camera.easeTo({ center: [170, 0], duration: 10 });
+        });
+
         t.end();
     });