One direction pinch zoom

src/ol/array.js

@@ -33,9 +33,12 @@ ol.array.binaryFindNearest = function(arr, target) {
 /**
  * @param {Array.<number>} arr Array.
  * @param {number} target Target.
+ * @param {number} direction 0 means return the nearest, > 0
+ *    means return the largest nearest, < 0 means return the
+ *    smallest nearest.
  * @return {number} Index.
  */
-ol.array.linearFindNearest = function(arr, target) {
+ol.array.linearFindNearest = function(arr, target, direction) {
   var n = arr.length;
   if (arr[0] <= target) {
     return 0;
@@ -43,17 +46,34 @@ ol.array.linearFindNearest = function(arr, target) {
     return n - 1;
   } else {
     var i;
-    for (i = 1; i < n; ++i) {
-      if (arr[i] == target) {
-        return i;
-      } else if (arr[i] < target) {
-        if (arr[i - 1] - target < target - arr[i]) {
+    if (direction > 0) {
+      for (i = 1; i < n; ++i) {
+        if (arr[i] < target) {
           return i - 1;
-        } else {
+        }
+      }
+    } else if (direction < 0) {
+      for (i = 1; i < n; ++i) {
+        if (arr[i] <= target) {
           return i;
         }
       }
+    } else {
+      for (i = 1; i < n; ++i) {
+        if (arr[i] == target) {
+          return i;
+        } else if (arr[i] < target) {
+          if (arr[i - 1] - target < target - arr[i]) {
+            return i - 1;
+          } else {
+            return i;
+          }
+        }
+      }
     }
+    // We should never get here, but the compiler complains
+    // if it finds a path for which no number is returned.
+    goog.asserts.assert(false);
     return n - 1;
   }
 };

src/ol/interaction/touchzoominteraction.js

@@ -29,6 +29,12 @@ ol.interaction.TouchZoom = function() {
    */
   this.lastDistance_;
 
+  /**
+   * @private
+   * @type {number}
+   */
+  this.lastScaleDelta_ = 1;
+
 };
 goog.inherits(ol.interaction.TouchZoom, ol.interaction.Touch);
 
@@ -53,6 +59,9 @@ ol.interaction.TouchZoom.prototype.handleTouchMove =
     scaleDelta = this.lastDistance_ / distance;
   }
   this.lastDistance_ = distance;
+  if (scaleDelta != 1.0) {
+    this.lastScaleDelta_ = scaleDelta;
+  }
 
   var map = mapBrowserEvent.map;
   var view = map.getView();
@@ -78,9 +87,12 @@ ol.interaction.TouchZoom.prototype.handleTouchEnd =
   if (this.targetTouches.length < 2) {
     var map = mapBrowserEvent.map;
     var view = map.getView();
-    // take the resolution constraint into account
+    // Zoom to final resolution, with an animation, and provide a
+    // direction not to zoom out/in if user was pinching in/out.
+    // Direction is > 0 if pinching out, and < 0 if pinching in.
+    var direction = this.lastScaleDelta_ - 1;
     view.zoom(map, view.getResolution(), undefined,
-        ol.interaction.TOUCHZOOM_ANIMATION_DURATION);
+        ol.interaction.TOUCHZOOM_ANIMATION_DURATION, direction);
     view.setHint(ol.ViewHint.INTERACTING, -1);
     return false;
   } else {
@@ -97,6 +109,7 @@ ol.interaction.TouchZoom.prototype.handleTouchStart =
   if (this.targetTouches.length >= 2) {
     var view = mapBrowserEvent.map.getView();
     this.lastDistance_ = undefined;
+    this.lastScaleDelta_ = 1;
     view.setHint(ol.ViewHint.INTERACTING, 1);
     return true;
   } else {

src/ol/resolutionconstraint.js

@@ -6,7 +6,7 @@ goog.require('ol.array');
 
 
 /**
- * @typedef {function((number|undefined), number): (number|undefined)}
+ * @typedef {function((number|undefined), number, number): (number|undefined)}
  */
 ol.ResolutionConstraintType;
 
@@ -20,7 +20,7 @@ ol.ResolutionConstraintType;
 ol.ResolutionConstraint.createContinuous =
     function(power, maxResolution, opt_minResolution) {
   var minResolution = opt_minResolution || 0;
-  return function(resolution, delta) {
+  return function(resolution, delta, direction) {
     if (goog.isDef(resolution)) {
       resolution /= Math.pow(power, delta);
       return goog.math.clamp(resolution, minResolution, maxResolution);
@@ -37,9 +37,9 @@ ol.ResolutionConstraint.createContinuous =
  */
 ol.ResolutionConstraint.createSnapToResolutions =
     function(resolutions) {
-  return function(resolution, delta) {
+  return function(resolution, delta, direction) {
     if (goog.isDef(resolution)) {
-      var z = ol.array.linearFindNearest(resolutions, resolution);
+      var z = ol.array.linearFindNearest(resolutions, resolution, direction);
       z = goog.math.clamp(z + delta, 0, resolutions.length - 1);
       return resolutions[z];
     } else {
@@ -57,10 +57,18 @@ ol.ResolutionConstraint.createSnapToResolutions =
  */
 ol.ResolutionConstraint.createSnapToPower =
     function(power, maxResolution, opt_maxLevel) {
-  return function(resolution, delta) {
+  return function(resolution, delta, direction) {
     if (goog.isDef(resolution)) {
+      var offset;
+      if (direction > 0) {
+        offset = 0;
+      } else if (direction < 0) {
+        offset = 1;
+      } else {
+        offset = 0.5;
+      }
       var oldLevel = Math.floor(
-          Math.log(maxResolution / resolution) / Math.log(power) + 0.5);
+          Math.log(maxResolution / resolution) / Math.log(power) + offset);
       var newLevel = Math.max(oldLevel + delta, 0);
       if (goog.isDef(opt_maxLevel)) {
         newLevel = Math.min(newLevel, opt_maxLevel);

src/ol/source/imagesource.js

@@ -100,7 +100,7 @@ ol.source.ImageSource.prototype.createImage =
 ol.source.ImageSource.prototype.findNearestResolution =
     function(resolution) {
   if (!goog.isNull(this.resolutions_)) {
-    var idx = ol.array.linearFindNearest(this.resolutions_, resolution);
+    var idx = ol.array.linearFindNearest(this.resolutions_, resolution, 0);
     resolution = this.resolutions_[idx];
   }
   return resolution;

src/ol/tilegrid/tilegrid.js

@@ -329,7 +329,7 @@ ol.tilegrid.TileGrid.prototype.getTileSize = function(z) {
  * @return {number} Z.
  */
 ol.tilegrid.TileGrid.prototype.getZForResolution = function(resolution) {
-  return ol.array.linearFindNearest(this.resolutions_, resolution);
+  return ol.array.linearFindNearest(this.resolutions_, resolution, 0);
 };
 
 

src/ol/view2d.js

@@ -193,7 +193,7 @@ ol.View2D.prototype.getView3D = function() {
 ol.View2D.prototype.fitExtent = function(extent, size) {
   this.setCenter(extent.getCenter());
   var resolution = this.getResolutionForExtent(extent, size);
-  resolution = this.constraints_.resolution(resolution, 0);
+  resolution = this.constraints_.resolution(resolution, 0, 0);
   this.setResolution(resolution);
 };
 
@@ -342,10 +342,19 @@ ol.View2D.prototype.rotateWithoutConstraints =
  * @param {number|undefined} resolution Resolution to go to.
  * @param {ol.Coordinate=} opt_anchor Anchor coordinate.
  * @param {number=} opt_duration Duration.
+ * @param {number=} opt_direction Zooming direction; > 0 indicates
+ *     zooming out, in which case the constraints system will select
+ *     the largest nearest resolution; < 0 indicates zooming in, in
+ *     which case the constraints system will select the smallest
+ *     nearest resolution; == 0 indicates that the zooming direction
+ *     is unknown/not relevant, in which case the constraints system
+ *     will select the nearest resolution. If not defined 0 is
+ *     assumed.
  */
 ol.View2D.prototype.zoom =
-    function(map, resolution, opt_anchor, opt_duration) {
-  resolution = this.constraints_.resolution(resolution, 0);
+    function(map, resolution, opt_anchor, opt_duration, opt_direction) {
+  var direction = opt_direction || 0;
+  resolution = this.constraints_.resolution(resolution, 0, direction);
   this.zoomWithoutConstraints(map, resolution, opt_anchor, opt_duration);
 };
 
@@ -359,7 +368,7 @@ ol.View2D.prototype.zoom =
 ol.View2D.prototype.zoomByDelta =
     function(map, delta, opt_anchor, opt_duration) {
   var currentResolution = this.getResolution();
-  var resolution = this.constraints_.resolution(currentResolution, delta);
+  var resolution = this.constraints_.resolution(currentResolution, delta, 0);
   this.zoomWithoutConstraints(map, resolution, opt_anchor, opt_duration);
 };