Update wheel-zoom.js

worka · Jul 26, 2019 · 0fc52d2 · 0fc52d2
1 parent bfae8f2
commit 0fc52d2
Showing 1 changed file with 16 additions and 0 deletions.
diff --git a/wheel-zoom.js b/wheel-zoom.js
@@ -161,6 +161,22 @@
             var shift_y = new_y - y;
 
             this.window.scrollTop += shift_y + (scroll_top_before_rescale - scroll_top_after_rescale);
+        },
+        _zoomUp: function () {
+            var event = new Event('mousewheel');
+
+            event.wheelDelta = 1;
+            event.detail = -1;
+
+            this._rescale(event);
+        },
+        _zoomDown: function () {
+            var event = new Event('mousewheel');
+
+            event.wheelDelta = -1;
+            event.detail = 1;
+
+            this._rescale(event);
         }
     };