Changelog tweak

One touch zoom in & out function #2077

changelog.txt

@@ -5,6 +5,7 @@ OPENSEADRAGON CHANGELOG
 
 * NEW BEHAVIOR: Setting the viewport rotation now animates by default (pass false for the new immediately parameter to disable) (#2136 @jonasengelmann)
 * DEPRECATION: Don't access the viewport's degrees property directly anymore; instead use setRotation and getRotation (#2136 @jonasengelmann)
+* New gesture: Double-click and drag to zoom (on by default for touch) (#2225 @HamzaTatheer)
 * Improved the constraints that keep the image in the viewer, specifically when zoomed out a lot (#2160 @joedf)
 * You can now provide an element for the navigator (as an alternative to an ID) (#1303 @cameronbaney, #2166 #2175 @joedf)
 * Now supporting IIIF "id" and "identifier" in addition to "@id" (#2173 @ahankinson)

src/control.js

@@ -74,6 +74,7 @@ $.ControlAnchor = {
  * @param {Element} container - the element to control will be anchored too.
  */
 $.Control = function ( element, options, container ) {
+
     var parent = element.parentNode;
     if (typeof options === 'number')
     {
@@ -150,6 +151,7 @@ $.Control = function ( element, options, container ) {
     } else {
         parent.appendChild( this.wrapper );
     }
+
 };
 
 /** @lends OpenSeadragon.Control.prototype */

src/openseadragon.js

@@ -341,6 +341,9 @@
   * @property {Boolean} [gestureSettingsMouse.clickToZoom=true] - Zoom on click gesture
   * @property {Boolean} [gestureSettingsMouse.dblClickToZoom=false] - Zoom on double-click gesture. Note: If set to true
   *     then clickToZoom should be set to false to prevent multiple zooms.
+  * @property {Boolean} [gestureSettingsMouse.dblClickDragToZoom=false] - Zoom on dragging through
+  * double-click gesture ( single click and next click to drag).  Note: If set to true
+  *     then clickToZoom should be set to false to prevent multiple zooms.
   * @property {Boolean} [gestureSettingsMouse.pinchToZoom=false] - Zoom on pinch gesture
   * @property {Boolean} [gestureSettingsMouse.zoomToRefPoint=true] - If zoomToRefPoint is true, the zoom is centered at the pointer position. Otherwise,
   *     the zoom is centered at the canvas center.
@@ -356,6 +359,10 @@
   * @property {Boolean} [gestureSettingsTouch.clickToZoom=false] - Zoom on click gesture
   * @property {Boolean} [gestureSettingsTouch.dblClickToZoom=true] - Zoom on double-click gesture. Note: If set to true
   *     then clickToZoom should be set to false to prevent multiple zooms.
+    * @property {Boolean} [gestureSettingsTouch.dblClickDragToZoom=true] - Zoom on dragging through
+  * double-click gesture ( single click and next click to drag).  Note: If set to true
+  *     then clickToZoom should be set to false to prevent multiple zooms.
+
   * @property {Boolean} [gestureSettingsTouch.pinchToZoom=true] - Zoom on pinch gesture
   * @property {Boolean} [gestureSettingsTouch.zoomToRefPoint=true] - If zoomToRefPoint is true, the zoom is centered at the pointer position. Otherwise,
   *     the zoom is centered at the canvas center.
@@ -386,6 +393,9 @@
   * @property {Boolean} [gestureSettingsUnknown.clickToZoom=false] - Zoom on click gesture
   * @property {Boolean} [gestureSettingsUnknown.dblClickToZoom=true] - Zoom on double-click gesture. Note: If set to true
   *     then clickToZoom should be set to false to prevent multiple zooms.
+  * @property {Boolean} [gestureSettingsUnknown.dblClickDragToZoom=false] - Zoom on dragging through
+  * double-click gesture ( single click and next click to drag).  Note: If set to true
+  *     then clickToZoom should be set to false to prevent multiple zooms.
   * @property {Boolean} [gestureSettingsUnknown.pinchToZoom=true] - Zoom on pinch gesture
   * @property {Boolean} [gestureSettingsUnknown.zoomToRefPoint=true] - If zoomToRefPoint is true, the zoom is centered at the pointer position. Otherwise,
   *     the zoom is centered at the canvas center.
@@ -400,6 +410,9 @@
   * @property {Number} [zoomPerScroll=1.2]
   *     The "zoom distance" per mouse scroll or touch pinch. <em><strong>Note:</strong> Setting this to 1.0 effectively disables the mouse-wheel zoom feature (also see gestureSettings[Mouse|Touch|Pen].scrollToZoom}).</em>
   *
+  * @property {Number} [zoomPerDblClickDrag=1.2]
+  *     The "zoom distance" per double-click mouse drag. <em><strong>Note:</strong> Setting this to 1.0 effectively disables the double-click-drag-to-Zoom feature (also see gestureSettings[Mouse|Touch|Pen].dblClickDragToZoom).</em>
+  *
   * @property {Number} [zoomPerSecond=1.0]
   *     Sets the zoom amount per second when zoomIn/zoomOut buttons are pressed and held.
   *     The value is a factor of the current zoom, so 1.0 (the default) disables zooming when the zoomIn/zoomOut buttons
@@ -1203,6 +1216,7 @@ function OpenSeadragon( options ){
                 scrollToZoom: true,
                 clickToZoom: true,
                 dblClickToZoom: false,
+                dblClickDragToZoom: false,
                 pinchToZoom: false,
                 zoomToRefPoint: true,
                 flickEnabled: false,
@@ -1215,6 +1229,7 @@ function OpenSeadragon( options ){
                 scrollToZoom: false,
                 clickToZoom: false,
                 dblClickToZoom: true,
+                dblClickDragToZoom: true,
                 pinchToZoom: true,
                 zoomToRefPoint: true,
                 flickEnabled: true,
@@ -1227,6 +1242,7 @@ function OpenSeadragon( options ){
                 scrollToZoom: false,
                 clickToZoom: true,
                 dblClickToZoom: false,
+                dblClickDragToZoom: false,
                 pinchToZoom: false,
                 zoomToRefPoint: true,
                 flickEnabled: false,
@@ -1239,6 +1255,7 @@ function OpenSeadragon( options ){
                 scrollToZoom: false,
                 clickToZoom: false,
                 dblClickToZoom: true,
+                dblClickDragToZoom: false,
                 pinchToZoom: true,
                 zoomToRefPoint: true,
                 flickEnabled: true,
@@ -1248,6 +1265,7 @@ function OpenSeadragon( options ){
             },
             zoomPerClick:           2,
             zoomPerScroll:          1.2,
+            zoomPerDblClickDrag:    1.2,
             zoomPerSecond:          1.0,
             blendTime:              0,
             alwaysBlend:            false,

src/viewer.js

@@ -212,7 +212,9 @@ $.Viewer = function( options ) {
         zoomFactor:        null,
         lastZoomTime:      null,
         fullPage:          false,
-        onfullscreenchange: null
+        onfullscreenchange: null,
+        lastClickTime: null,
+        draggingToZoom: false,
     };
 
     this._sequenceIndex = 0;
@@ -2854,6 +2856,8 @@ function onCanvasKeyPress( event ) {
     }
 }
 
+
+
 function onCanvasClick( event ) {
     var gestureSettings;
 
@@ -2893,17 +2897,31 @@ function onCanvasClick( 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);
 
+
     if ( !canvasClickEventArgs.preventDefaultAction && this.viewport && event.quick ) {
         gestureSettings = this.gestureSettingsByDeviceType( event.pointerType );
-        if ( gestureSettings.clickToZoom ) {
+
+        if (gestureSettings.clickToZoom === true){
             this.viewport.zoomBy(
                 event.shift ? 1.0 / this.zoomPerClick : this.zoomPerClick,
                 gestureSettings.zoomToRefPoint ? this.viewport.pointFromPixel( event.position, true ) : null
             );
             this.viewport.applyConstraints();
         }
+
+        if( gestureSettings.dblClickDragToZoom){
+            if(THIS[ this.hash ].draggingToZoom === true){
+                THIS[ this.hash ].lastClickTime = null;
+                THIS[ this.hash ].draggingToZoom = false;
+            }
+            else{
+                THIS[ this.hash ].lastClickTime = $.now();
+            }
+        }
+
     }
 }
 
@@ -2983,7 +3001,13 @@ function onCanvasDrag( event ) {
 
     gestureSettings = this.gestureSettingsByDeviceType( event.pointerType );
 
-    if ( gestureSettings.dragToPan && !canvasDragEventArgs.preventDefaultAction && this.viewport ) {
+    if(!canvasDragEventArgs.preventDefaultAction && this.viewport){
+
+        if (gestureSettings.dblClickDragToZoom && THIS[ this.hash ].draggingToZoom){
+            var factor = Math.pow( this.zoomPerDblClickDrag, event.delta.y / 50);
+            this.viewport.zoomBy(factor);
+        }
+        else if (gestureSettings.dragToPan && !THIS[ this.hash ].draggingToZoom) {
             if( !this.panHorizontal ){
                 event.delta.x = 0;
             }
@@ -3014,12 +3038,15 @@ function onCanvasDrag( event ) {
                     event.delta.y = 0;
                 }
             }
-
             this.viewport.panBy( this.viewport.deltaPointsFromPixels( event.delta.negate() ), gestureSettings.flickEnabled && !this.constrainDuringPan);
         }
+
+    }
+
 }
 
 function onCanvasDragEnd( event ) {
+    var gestureSettings;
     var canvasDragEndEventArgs = {
         tracker: event.eventSource,
         pointerType: event.pointerType,
@@ -3050,9 +3077,11 @@ function onCanvasDragEnd( event ) {
      */
      this.raiseEvent('canvas-drag-end', canvasDragEndEventArgs);
 
+     gestureSettings = this.gestureSettingsByDeviceType( event.pointerType );
+
     if (!canvasDragEndEventArgs.preventDefaultAction && this.viewport) {
-        var gestureSettings = this.gestureSettingsByDeviceType(event.pointerType);
+        if ( !THIS[ this.hash ].draggingToZoom &&
-        if (gestureSettings.flickEnabled &&
+            gestureSettings.flickEnabled &&
             event.speed >= gestureSettings.flickMinSpeed) {
             var amplitudeX = 0;
             if (this.panHorizontal) {
@@ -3072,6 +3101,13 @@ function onCanvasDragEnd( event ) {
         }
         this.viewport.applyConstraints();
     }
+
+
+    if( gestureSettings.dblClickDragToZoom && THIS[ this.hash ].draggingToZoom === true ){
+        THIS[ this.hash ].draggingToZoom = false;
+    }
+
+
 }
 
 function onCanvasEnter( event ) {
@@ -3135,6 +3171,8 @@ function onCanvasLeave( event ) {
 }
 
 function onCanvasPress( event ) {
+    var gestureSettings;
+
     /**
      * Raised when the primary mouse button is pressed or touch starts on the {@link OpenSeadragon.Viewer#canvas} element.
      *
@@ -3158,6 +3196,24 @@ function onCanvasPress( event ) {
         insideElementReleased: event.insideElementReleased,
         originalEvent: event.originalEvent
     });
+
+
+    gestureSettings = this.gestureSettingsByDeviceType( event.pointerType );
+    if ( gestureSettings.dblClickDragToZoom ){
+        var lastClickTime = THIS[ this.hash ].lastClickTime;
+        var currClickTime = $.now();
+
+        if ( lastClickTime === null) {
+            return;
+        }
+
+        if ((currClickTime - lastClickTime) < this.dblClickTimeThreshold) {
+            THIS[ this.hash ].draggingToZoom = true;
+        }
+
+        THIS[ this.hash ].lastClickTime = null;
+    }
+
 }
 
 function onCanvasRelease( event ) {