Changelog for #2158

Fix wrong center point on pinch zoom

changelog.txt

@@ -20,6 +20,7 @@ OPENSEADRAGON CHANGELOG
 * Now if you pass an error handler into makeAjaxRequest, it doesn't report errors into the console (#2142 @Aiosa)
 * Fixed error caused by attaching MouseTracker to the page's document element (#2145 @tdiprima)
 * Added fallback and deprecation warning for Viewer.buttons (which got changed to buttonGroup in 3.0.0) (#2153 @devbyjonah)
+* Pinch to zoom now zooms around the center of the pinch, rather than the center of the viewer (#2158 @cavenel)
 
 3.0.0:
 

src/viewer.js

@@ -3289,9 +3289,6 @@ function onCanvasPinch( event ) {
         if ( gestureSettings.pinchToZoom &&
                     (!canvasPinchEventArgs.preventDefaultPanAction || !canvasPinchEventArgs.preventDefaultZoomAction) ) {
             centerPt = this.viewport.pointFromPixel( event.center, true );
-            if ( !canvasPinchEventArgs.preventDefaultZoomAction ) {
-                this.viewport.zoomBy( event.distance / event.lastDistance, centerPt, true );
-            }
             if ( gestureSettings.zoomToRefPoint && !canvasPinchEventArgs.preventDefaultPanAction ) {
                 lastCenterPt = this.viewport.pointFromPixel( event.lastCenter, true );
                 panByPt = lastCenterPt.minus( centerPt );
@@ -3303,6 +3300,9 @@ function onCanvasPinch( event ) {
                 }
                 this.viewport.panBy(panByPt, true);
             }
+            if ( !canvasPinchEventArgs.preventDefaultZoomAction ) {
+                this.viewport.zoomBy( event.distance / event.lastDistance, centerPt, true );
+            }
             this.viewport.applyConstraints();
         }
         if ( gestureSettings.pinchRotate && !canvasPinchEventArgs.preventDefaultRotateAction ) {