From 948e792ddd286ffccd7a89deaab5feba95d7a29b Mon Sep 17 00:00:00 2001
From: Tim Schaub <tim.schaub@gmail.com>
Date: Thu, 21 Jun 2012 19:58:35 +0200
Subject: [PATCH] Bounds transforms.

---
 src/api/bounds.js           | 14 ++++++++
 src/ol/Bounds.js            | 64 +++++++++++++++++++++++++++++++++++++
 test/spec/ol/Bounds.test.js | 36 +++++++++++++++++++++
 3 files changed, 114 insertions(+)

diff --git a/src/api/bounds.js b/src/api/bounds.js
index eb87871275..89bf64de01 100644
--- a/src/api/bounds.js
+++ b/src/api/bounds.js
@@ -132,3 +132,17 @@ ol.Bounds.prototype.maxY = function(opt_arg){
         return this.getMaxY();
     }
 };
+
+/**
+ * Transform this node into another coordinate reference system.  Returns a new
+ * bounds instead of modifying this bounds.
+ *
+ * @param {ol.Projection|string} proj Target projection (or string identifier).
+ * @return {ol.Bounds} A new bounds in the target projection.
+ */
+ol.Bounds.prototype.transform = function(proj) {
+    if (goog.isString(proj)) {
+        proj = new ol.Projection(proj);
+    }
+    return this.doTransform(proj);
+};
diff --git a/src/ol/Bounds.js b/src/ol/Bounds.js
index 396361acb9..36b40e3086 100644
--- a/src/ol/Bounds.js
+++ b/src/ol/Bounds.js
@@ -1,7 +1,11 @@
 goog.provide('ol.Bounds');
+
 goog.require('ol.UnreferencedBounds');
+goog.require('ol.Loc');
 goog.require('ol.Projection');
 
+goog.require('goog.string.format')
+
 /**
  * @export
  * @constructor
@@ -39,3 +43,63 @@ ol.Bounds.prototype.setProjection = function(projection) {
     this.projection_ = projection;
 };
 
+/**
+ * Determine if this bounds intersects the target bounds (bounds that only
+ * touch are considered intersecting).
+ *
+ * @param {ol.Bounds} bounds Target bounds.
+ * @return {boolean} The provided bounds intersects this bounds.
+ */
+ol.Bounds.prototype.intersects = function(bounds) {
+    var otherProj = bounds.getProjection();
+    if (!goog.isNull(otherProj) && !goog.isNull(this.projection_)) {
+        bounds = bounds.transform(this.projection_);
+    }
+    return goog.base(this, "intersects", bounds.toUnreferencedBounds());
+};
+
+/**
+ * Transform this node into another coordinate reference system.  Returns a new
+ * bounds instead of modifying this bounds.
+ *
+ * @param {ol.Projection} proj Target projection.
+ * @return {ol.Bounds} A new bounds in the target projection.
+ */
+ol.Bounds.prototype.doTransform = function(proj) {
+    if (goog.isNull(this.projection_)) {
+        throw new Error("Bounds must have a projection before transforming.");
+    }
+    var tl = new ol.Loc(
+        this.minX_, this.maxY_, undefined, this.projection_).transform(proj);
+    var tr = new ol.Loc(
+        this.maxX_, this.maxY_, undefined, this.projection_).transform(proj);
+    var bl = new ol.Loc(
+        this.minX_, this.minY_, undefined, this.projection_).transform(proj);
+    var br = new ol.Loc(
+        this.maxX_, this.minY_, undefined, this.projection_).transform(proj);
+        
+    var x = [tl.getX(), tr.getX(), bl.getX(), br.getX()].sort();
+    var y = [tl.getY(), tr.getY(), bl.getY(), br.getY()].sort();
+    
+    return new ol.Bounds(x[0], y[0], x[3], y[3], proj);
+};
+
+/**
+ * Return a bbox string for this bounds.
+ *
+ * @return {string} The "minx,miny,maxx,maxy" representation of this bounds.
+ */
+ol.Bounds.prototype.toBBOX = function() {
+    return goog.string.format(
+        '%f,%f,%f,%f', this.minX_, this.minY_, this.maxX_, this.maxY_);
+};
+
+/**
+ * Cast this bounds into an unreferenced bounds.
+ * 
+ * @returns {ol.UnreferencedBounds}
+ */
+ol.Bounds.prototype.toUnreferencedBounds = function() {
+    return new ol.UnreferencedBounds(
+        this.getMinX(), this.getMinY(), this.getMaxX(), this.getMaxY());
+};
diff --git a/test/spec/ol/Bounds.test.js b/test/spec/ol/Bounds.test.js
index 909ff292b8..51b9032a95 100644
--- a/test/spec/ol/Bounds.test.js
+++ b/test/spec/ol/Bounds.test.js
@@ -29,5 +29,41 @@ describe("ol.Bounds", function() {
         });
         
     });
+    
+    describe("transforming bounds", function() {
+        
+        var gg = new ol.Projection("EPSG:4326");
+        var sm = new ol.Projection("EPSG:900913");
+
+        var bounds = new ol.Bounds(10, -10, 20, 10, gg);
+        
+        // approximate bbox array
+        function bbox(bounds) {
+            var mult = Math.pow(10, 6); // six figs
+            return [
+                Math.round(bounds.getMinX() * mult) / mult,
+                Math.round(bounds.getMinY() * mult) / mult,
+                Math.round(bounds.getMaxX() * mult) / mult,
+                Math.round(bounds.getMaxY() * mult) / mult
+            ];
+        }
+        
+        it("doesn't mind a null transform", function() {
+            var trans = bounds.transform(new ol.Projection("foo")); 
+            expect(bbox(bounds)).toEqual([10, -10, 20, 10]);
+        });
+        
+        it("transforms from geographic to spherical mercator", function() {
+            var trans = bounds.transform(sm);
+            expect(bbox(trans)).toEqual([1113194.907778, -1118889.974702, 2226389.815556, 1118889.974702]);
+        });
+
+        it("transforms from spherical mercator to geographic", function() {
+            var trans = bounds.transform(sm);
+            var back = trans.transform(gg);
+            expect(bbox(back)).toEqual([10, -10, 20, 10]);
+        });
+        
+    });
 
 });