add keypress handler's event

src/viewer.js

@@ -295,6 +295,7 @@ $.Viewer = function( options ) {
         dblClickDistThreshold:    this.dblClickDistThreshold,
         contextMenuHandler:       $.delegate( this, onCanvasContextMenu ),
         keyDownHandler:           $.delegate( this, onCanvasKeyDown ),
+        keyHandler:               $.delegate( this, onCanvasKeyPress ),
         clickHandler:             $.delegate( this, onCanvasClick ),
         dblClickHandler:          $.delegate( this, onCanvasDblClick ),
         dragHandler:              $.delegate( this, onCanvasDrag ),
@@ -2884,6 +2885,29 @@ function onCanvasKeyDown( event ) {
     }
 }
 
+function onCanvasKeyPress( event ) {
+    var canvasKeyPressEventArgs = {
+      originalEvent: event.originalEvent,
+      preventDefaultAction: false,
+      preventVerticalPan: event.preventVerticalPan || !this.panVertical,
+      preventHorizontalPan: event.preventHorizontalPan || !this.panHorizontal
+    };
+
+    /**
+     * Raised when a keyboard key is pressed and the focus is on the {@link OpenSeadragon.Viewer#canvas} element.
+     *
+     * @event canvas-key-press
+     * @memberof OpenSeadragon.Viewer
+     * @type {object}
+     * @property {OpenSeadragon.Viewer} eventSource - A reference to the Viewer which raised this event.
+     * @property {Object} originalEvent - The original DOM event.
+     * @property {Boolean} preventDefaultAction - Set to true to prevent default keyboard behaviour. Default: false.
+     * @property {Boolean} preventVerticalPan - Set to true to prevent keyboard vertical panning. Default: false.
+     * @property {Boolean} preventHorizontalPan - Set to true to prevent keyboard horizontal panning. Default: false.
+     * @property {?Object} userData - Arbitrary subscriber-defined object.
+     */
+    this.raiseEvent('canvas-key-press', canvasKeyPressEventArgs);
+}
 function onCanvasClick( event ) {
     var gestureSettings;