From fb32cc719818ee5e93a149d9cb620c639b74a382 Mon Sep 17 00:00:00 2001
From: Tom <tmpearce@gmail.com>
Date: Mon, 13 Mar 2023 22:19:06 -0400
Subject: [PATCH] add after-resize event

---
 src/viewport.js | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/viewport.js b/src/viewport.js
index a9c3913a..11fc1558 100644
--- a/src/viewport.js
+++ b/src/viewport.js
@@ -1078,7 +1078,10 @@ $.Viewport.prototype = {
 
         if( this.viewer ){
             /**
-             * Raised when the viewer is resized (see {@link OpenSeadragon.Viewport#resize}).
+             * Raised when a viewer resize operation is initiated (see {@link OpenSeadragon.Viewport#resize}).
+             * This event happens before the viewport bounds have been updated.
+             * See also {@link OpenSeadragon.Viewer#after-resize} which reflects
+             * the new viewport bounds following the resize action.
              *
              * @event resize
              * @memberof OpenSeadragon.Viewer
@@ -1094,7 +1097,29 @@ $.Viewport.prototype = {
             });
         }
 
-        return this.fitBounds( newBounds, true );
+        var output = this.fitBounds( newBounds, true );
+
+        if( this.viewer ){
+            /**
+             * Raised after the viewer is resized (see {@link OpenSeadragon.Viewport#resize}).
+             * See also {@link OpenSeadragon.Viewer#resize} event which happens
+             * before the new bounds have been calculated and applied.
+             *
+             * @event after-resize
+             * @memberof OpenSeadragon.Viewer
+             * @type {object}
+             * @property {OpenSeadragon.Viewer} eventSource - A reference to the Viewer which raised this event.
+             * @property {OpenSeadragon.Point} newContainerSize
+             * @property {Boolean} maintain
+             * @property {?Object} userData - Arbitrary subscriber-defined object.
+             */
+            this.viewer.raiseEvent( 'after-resize', {
+                newContainerSize: newContainerSize,
+                maintain: maintain
+            });
+        }
+
+        return output;
     },
 
     // private