From e9c340b9574d053f4b427d94fc6274fec2463946 Mon Sep 17 00:00:00 2001
From: Tim Schaub <tim.schaub@gmail.com>
Date: Mon, 27 Mar 2017 14:18:16 -0600
Subject: [PATCH] Allow min/max zoom to be set on a view

---
 src/ol/view.js            | 47 ++++++++++++++++++++++++++++
 test/spec/ol/view.test.js | 66 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 113 insertions(+)

diff --git a/src/ol/view.js b/src/ol/view.js
index 89e0bf4270..333efca9f4 100644
--- a/src/ol/view.js
+++ b/src/ol/view.js
@@ -190,6 +190,33 @@ ol.View.prototype.applyOptions_ = function(options) {
 
 };
 
+/**
+ * Get an updated version of the view options used to construct the view.  The
+ * current resolution (or zoom), center, and rotation are applied to any stored
+ * options.  The provided options can be uesd to apply new min/max zoom or
+ * resolution limits.
+ * @param {olx.ViewOptions} newOptions New options to be applied.
+ * @return {olx.ViewOptions} New options updated with the current view state.
+ */
+ol.View.prototype.getUpdatedOptions_ = function(newOptions) {
+  var options = ol.obj.assign({}, this.options_);
+
+  // preserve resolution (or zoom)
+  if (options.resolution !== undefined) {
+    options.resolution = this.getResolution();
+  } else {
+    options.zoom = this.getZoom();
+  }
+
+  // preserve center
+  options.center = this.getCenter();
+
+  // preserve rotation
+  options.rotation = this.getRotation();
+
+  return ol.obj.assign({}, options, newOptions);
+};
+
 
 /**
  * Animate the view.  The view's center, zoom (or resolution), and rotation
@@ -559,6 +586,16 @@ ol.View.prototype.getMaxZoom = function() {
 };
 
 
+/**
+ * Set a new maximum zoom level for the view.
+ * @param {number} zoom The maximum zoom level.
+ * @api
+ */
+ol.View.prototype.setMaxZoom = function(zoom) {
+  this.applyOptions_(this.getUpdatedOptions_({maxZoom: zoom}));
+};
+
+
 /**
  * Get the minimum zoom level for the view.
  * @return {number} The minimum zoom level.
@@ -569,6 +606,16 @@ ol.View.prototype.getMinZoom = function() {
 };
 
 
+/**
+ * Set a new minimum zoom level for the view.
+ * @param {number} zoom The minimum zoom level.
+ * @api
+ */
+ol.View.prototype.setMinZoom = function(zoom) {
+  this.applyOptions_(this.getUpdatedOptions_({minZoom: zoom}));
+};
+
+
 /**
  * Get the view projection.
  * @return {ol.proj.Projection} The projection of the view.
diff --git a/test/spec/ol/view.test.js b/test/spec/ol/view.test.js
index d12505d538..cf06ec2fea 100644
--- a/test/spec/ol/view.test.js
+++ b/test/spec/ol/view.test.js
@@ -330,6 +330,72 @@ describe('ol.View', function() {
 
   });
 
+  describe('#getUpdatedOptions_()', function() {
+
+    it('applies minZoom to constructor options', function() {
+      var view = new ol.View({
+        center: [0, 0],
+        minZoom: 2,
+        zoom: 10
+      });
+      var options = view.getUpdatedOptions_({minZoom: 3});
+
+      expect(options.center).to.eql([0, 0]);
+      expect(options.minZoom).to.eql(3);
+      expect(options.zoom).to.eql(10);
+    });
+
+    it('applies the current zoom', function() {
+      var view = new ol.View({
+        center: [0, 0],
+        zoom: 10
+      });
+      view.setZoom(8);
+      var options = view.getUpdatedOptions_();
+
+      expect(options.center).to.eql([0, 0]);
+      expect(options.zoom).to.eql(8);
+    });
+
+    it('applies the current resolution if resolution was originally supplied', function() {
+      var view = new ol.View({
+        center: [0, 0],
+        resolution: 1000
+      });
+      view.setResolution(500);
+      var options = view.getUpdatedOptions_();
+
+      expect(options.center).to.eql([0, 0]);
+      expect(options.resolution).to.eql(500);
+    });
+
+    it('applies the current center', function() {
+      var view = new ol.View({
+        center: [0, 0],
+        zoom: 10
+      });
+      view.setCenter([1, 2]);
+      var options = view.getUpdatedOptions_();
+
+      expect(options.center).to.eql([1, 2]);
+      expect(options.zoom).to.eql(10);
+    });
+
+    it('applies the current rotation', function() {
+      var view = new ol.View({
+        center: [0, 0],
+        zoom: 10
+      });
+      view.setRotation(Math.PI / 6);
+      var options = view.getUpdatedOptions_();
+
+      expect(options.center).to.eql([0, 0]);
+      expect(options.zoom).to.eql(10);
+      expect(options.rotation).to.eql(Math.PI / 6);
+    });
+
+  });
+
   describe('#animate()', function() {
 
     var originalRequestAnimationFrame = window.requestAnimationFrame;