From c38188927ef73a98ae90fe6bb7e16b64d0c32ff9 Mon Sep 17 00:00:00 2001
From: Mark Salsbery <>
Date: Wed, 10 Mar 2021 13:45:15 -0800
Subject: [PATCH] Added preventDefault option to
 MouseTracker.contextMenuHandler and Viewer 'canvas-contextmenu' event args

---
 changelog.txt       |  1 +
 src/mousetracker.js | 32 ++++++++++++++++++--------------
 src/viewer.js       | 16 +++++++++++-----
 3 files changed, 30 insertions(+), 19 deletions(-)

diff --git a/changelog.txt b/changelog.txt
index 1c325eba..b1f80fda 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -36,6 +36,7 @@ OPENSEADRAGON CHANGELOG
 * Added additional documentation for the zoomPerSecond viewer option (#1872 @msalsbery)
 * MouseTracker: Per #1863, dropped support for Internet Explorer < 11 (#1872 @msalsbery)
 * Fixed simulated drag events in navigator tests (#1949 @msalsbery)
+* Added preventDefault option to MouseTracker.contextMenuHandler and Viewer 'canvas-contextmenu' event args (# @msalsbery)
 
 2.4.2:
 
diff --git a/src/mousetracker.js b/src/mousetracker.js
index 4aefd249..1c268ee2 100644
--- a/src/mousetracker.js
+++ b/src/mousetracker.js
@@ -280,7 +280,6 @@
                                 this.dragHandler || this.dragEndHandler ||
                                 this.pinchHandler );
         this.hasScrollHandler = !!this.scrollHandler;
-        this.hasContextMenuHandler = !!this.contextMenuHandler;
 
         if (this.exitHandler) {
             $.console.error("MouseTracker.exitHandler is deprecated. Use MouseTracker.leaveHandler instead.");
@@ -402,6 +401,8 @@
          *      The position of the event relative to the tracked element.
          * @param {Object} event.originalEvent
          *      The original event object.
+         * @param {Boolean} event.preventDefault
+         *      Set to true to prevent the default user-agent's handling of the contextmenu event.
          * @param {Object} event.userData
          *      Arbitrary user-defined object.
          */
@@ -1942,6 +1943,8 @@
     function onContextMenu( tracker, event ) {
         //$.console.log('contextmenu ' + (tracker.userData ? tracker.userData.toString() : '') + ' ' + (event.target === tracker.element ? 'tracker.element' : ''));
 
+        var eventArgs = null;
+
         var eventInfo = {
             originalEvent: event,
             eventType: 'contextmenu',
@@ -1952,17 +1955,18 @@
 
         // ContextMenu
         if ( tracker.contextMenuHandler && !eventInfo.preventGesture && !eventInfo.defaultPrevented ) {
-            tracker.contextMenuHandler(
-                {
-                    eventSource:          tracker,
-                    position:             getPointRelativeToAbsolute( getMouseAbsolute( event ), tracker.element ),
-                    originalEvent:        eventInfo.originalEvent,
-                    userData:             tracker.userData
-                }
-            );
+            eventArgs = {
+                eventSource:          tracker,
+                position:             getPointRelativeToAbsolute( getMouseAbsolute( event ), tracker.element ),
+                originalEvent:        eventInfo.originalEvent,
+                preventDefault:       eventInfo.preventDefault || eventInfo.defaultPrevented,
+                userData:             tracker.userData
+            };
+
+            tracker.contextMenuHandler( eventArgs );
         }
 
-        if ( eventInfo.preventDefault && !eventInfo.defaultPrevented ) {
+        if ( ( eventArgs && eventArgs.preventDefault ) || ( eventInfo.preventDefault && !eventInfo.defaultPrevented ) ) {
             $.cancelEvent( event );
         }
         if ( eventInfo.stopPropagation ) {
@@ -2810,7 +2814,7 @@
             case 'pointerdown':
                 eventInfo.isStopable = true;
                 eventInfo.isCancelable = true;
-                eventInfo.preventDefault = false;//tracker.hasGestureHandlers;
+                eventInfo.preventDefault = false; // updatePointerDown() may set true (tracker.hasGestureHandlers)
                 eventInfo.preventGesture = !tracker.hasGestureHandlers;
                 eventInfo.stopPropagation = false;
                 break;
@@ -2824,7 +2828,7 @@
             case 'wheel':
                 eventInfo.isStopable = true;
                 eventInfo.isCancelable = true;
-                eventInfo.preventDefault = false;//tracker.hasScrollHandler;
+                eventInfo.preventDefault = false; // handleWheelEvent() may set true (tracker.hasScrollHandler)
                 eventInfo.preventGesture = !tracker.hasScrollHandler;
                 eventInfo.stopPropagation = false;
                 break;
@@ -2854,8 +2858,8 @@
             case 'contextmenu':
                 eventInfo.isStopable = true;
                 eventInfo.isCancelable = true;
-                eventInfo.preventDefault = false;//tracker.hasContextMenuHandler;
-                eventInfo.preventGesture = true;//!tracker.hasContextMenuHandler;
+                eventInfo.preventDefault = false;
+                eventInfo.preventGesture = false;
                 eventInfo.stopPropagation = false;
                 break;
             case 'pointerenter':
diff --git a/src/viewer.js b/src/viewer.js
index db1e8a23..21d6f469 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -2546,6 +2546,13 @@ function onBlur(){
 }
 
 function onCanvasContextMenu( event ) {
+    var eventArgs = {
+        tracker: event.eventSource,
+        position: event.position,
+        originalEvent: event.originalEvent,
+        preventDefault: event.preventDefault
+    };
+
     /**
      * Raised when a contextmenu event occurs in the {@link OpenSeadragon.Viewer#canvas} element.
      *
@@ -2556,13 +2563,12 @@ function onCanvasContextMenu( event ) {
      * @property {OpenSeadragon.MouseTracker} tracker - A reference to the MouseTracker which originated this event.
      * @property {OpenSeadragon.Point} position - The position of the event relative to the tracked element.
      * @property {Object} originalEvent - The original DOM event.
+     * @property {Boolean} preventDefault - Set to true to prevent the default user-agent's handling of the contextmenu event.
      * @property {?Object} userData - Arbitrary subscriber-defined object.
      */
-    this.raiseEvent( 'canvas-contextmenu', {
-        tracker: event.eventSource,
-        position: event.position,
-        originalEvent: event.originalEvent
-    });
+    this.raiseEvent( 'canvas-contextmenu', eventArgs );
+
+    event.preventDefault = eventArgs.preventDefault;
 }
 
 function onCanvasKeyDown( event ) {