From 3cdd94e46548214f9bf335a49d93867526d5fc4c Mon Sep 17 00:00:00 2001
From: jonasengelmann <40031476+jonasengelmann@users.noreply.github.com>
Date: Wed, 29 Jun 2022 19:47:26 +0200
Subject: [PATCH] constrained rotation to shortest path

---
 src/viewport.js          | 11 ++++++++++-
 test/modules/viewport.js |  2 +-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/viewport.js b/src/viewport.js
index 203fe07f..9a058968 100644
--- a/src/viewport.js
+++ b/src/viewport.js
@@ -917,7 +917,16 @@ $.Viewport.prototype = {
         if (immediately) {
             this.degreesSpring.resetTo(degrees);
         } else {
-            this.degreesSpring.springTo(degrees);
+            var from = $.euclideanModulo(this.degreesSpring.current.value, 360);
+            this.degreesSpring.resetTo(from);
+            var to = $.euclideanModulo(degrees, 360);
+            var diff = to - from;
+            if (diff > 180) {
+                to -= 360;
+            } else if (diff < -180) {
+                to += 360;
+            }
+            this.degreesSpring.springTo(to);
         }
 
         this._setContentBounds(
diff --git a/test/modules/viewport.js b/test/modules/viewport.js
index 59597060..804af1e9 100644
--- a/test/modules/viewport.js
+++ b/test/modules/viewport.js
@@ -1075,7 +1075,7 @@
 
             viewport.setRotation(400);
             assert.strictEqual(viewport.getRotation(true), 0, 'current rotation is not changed');
-            assert.strictEqual(viewport.getRotation(false), 400, 'target rotation is set correctly');
+            assert.strictEqual(viewport.getRotation(false), 40, 'target rotation is set correctly');
 
             viewport.setRotation(200, true);
             assert.strictEqual(viewport.getRotation(true), 200, 'current rotation is set correctly');