From d5031835daf7a18c406d19f49676371755c69692 Mon Sep 17 00:00:00 2001
From: kinto <simone.scremin@gmail.com>
Date: Tue, 14 Mar 2017 16:08:52 +0100
Subject: [PATCH 1/2] manage preventDefaultAction flag inside the canvas-click
 viewer event. Trigger the canvas-click event before default click zoom
 happens on the viewer

---
 src/viewer.js | 38 +++++++++++++++++++++-----------------
 1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/src/viewer.js b/src/viewer.js
index cea725a3..69c4b133 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -2463,16 +2463,15 @@ function onCanvasClick( event ) {
         this.canvas.focus();
     }
 
-    if ( !event.preventDefaultAction && this.viewport && event.quick ) {
-        gestureSettings = this.gestureSettingsByDeviceType( event.pointerType );
-        if ( gestureSettings.clickToZoom ) {
-            this.viewport.zoomBy(
-                event.shift ? 1.0 / this.zoomPerClick : this.zoomPerClick,
-                this.viewport.pointFromPixel( event.position, true )
-            );
-            this.viewport.applyConstraints();
-        }
-    }
+    var canvasClickEventArgs = {
+        tracker: event.eventSource,
+        position: event.position,
+        quick: event.quick,
+        shift: event.shift,
+        originalEvent: event.originalEvent,
+        preventDefaultAction: event.preventDefaultAction
+    };
+
     /**
      * Raised when a mouse press/release or touch/remove occurs on the {@link OpenSeadragon.Viewer#canvas} element.
      *
@@ -2487,13 +2486,18 @@ function onCanvasClick( event ) {
      * @property {Object} originalEvent - The original DOM event.
      * @property {?Object} userData - Arbitrary subscriber-defined object.
      */
-    this.raiseEvent( 'canvas-click', {
-        tracker: event.eventSource,
-        position: event.position,
-        quick: event.quick,
-        shift: event.shift,
-        originalEvent: event.originalEvent
-    });
+    this.raiseEvent( 'canvas-click', canvasClickEventArgs);
+
+    if ( !canvasClickEventArgs.preventDefaultAction && this.viewport && event.quick ) {
+        gestureSettings = this.gestureSettingsByDeviceType( event.pointerType );
+        if ( gestureSettings.clickToZoom ) {
+            this.viewport.zoomBy(
+                event.shift ? 1.0 / this.zoomPerClick : this.zoomPerClick,
+                this.viewport.pointFromPixel( event.position, true )
+            );
+            this.viewport.applyConstraints();
+        }
+    }
 }
 
 function onCanvasDblClick( event ) {

From bc5e235822646b5da318f9307da11b4a54304d17 Mon Sep 17 00:00:00 2001
From: kinto <simone.scremin@gmail.com>
Date: Tue, 14 Mar 2017 19:23:07 +0100
Subject: [PATCH 2/2] Add comment instructions for using preventDefaultAction
 parameter in canvas-click event

---
 src/viewer.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/viewer.js b/src/viewer.js
index 69c4b133..d3e68534 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -2484,6 +2484,7 @@ function onCanvasClick( event ) {
      * @property {Boolean} quick - True only if the clickDistThreshold and clickTimeThreshold are both passed. Useful for differentiating between clicks and drags.
      * @property {Boolean} shift - True if the shift key was pressed during this event.
      * @property {Object} originalEvent - The original DOM event.
+     * @property {Boolean} preventDefaultAction - Set to true to prevent default click to zoom behaviour. Default: false.
      * @property {?Object} userData - Arbitrary subscriber-defined object.
      */
     this.raiseEvent( 'canvas-click', canvasClickEventArgs);