From d713c9fea69aaa7a86771bb2d68209ee107c618f Mon Sep 17 00:00:00 2001
From: Tim Schaub <tim.schaub@gmail.com>
Date: Fri, 3 Feb 2017 12:56:03 -0700
Subject: [PATCH] Disallow pinch zooming beyond min/max resolution

---
 src/ol/interaction/pinchzoom.js | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/ol/interaction/pinchzoom.js b/src/ol/interaction/pinchzoom.js
index 3d42390f2e..68409d3124 100644
--- a/src/ol/interaction/pinchzoom.js
+++ b/src/ol/interaction/pinchzoom.js
@@ -81,13 +81,25 @@ ol.interaction.PinchZoom.handleDragEvent_ = function(mapBrowserEvent) {
     scaleDelta = this.lastDistance_ / distance;
   }
   this.lastDistance_ = distance;
-  if (scaleDelta != 1.0) {
-    this.lastScaleDelta_ = scaleDelta;
-  }
+
 
   var map = mapBrowserEvent.map;
   var view = map.getView();
   var resolution = view.getResolution();
+  var maxResolution = view.getMaxResolution();
+  var minResolution = view.getMinResolution();
+  var newResolution = resolution * scaleDelta;
+  if (newResolution > maxResolution) {
+    scaleDelta = maxResolution / resolution;
+    newResolution = maxResolution;
+  } else if (newResolution < minResolution) {
+    scaleDelta = minResolution / resolution;
+    newResolution = minResolution;
+  }
+
+  if (scaleDelta != 1.0) {
+    this.lastScaleDelta_ = scaleDelta;
+  }
 
   // scale anchor point.
   var viewportPosition = map.getViewport().getBoundingClientRect();
@@ -98,8 +110,7 @@ ol.interaction.PinchZoom.handleDragEvent_ = function(mapBrowserEvent) {
 
   // scale, bypass the resolution constraint
   map.render();
-  ol.interaction.Interaction.zoomWithoutConstraints(
-      view, resolution * scaleDelta, this.anchor_);
+  ol.interaction.Interaction.zoomWithoutConstraints(view, newResolution, this.anchor_);
 };