From a21cb7dd9203adb8363fa96a0749d32171349425 Mon Sep 17 00:00:00 2001
From: Ash Furrow <ash@ashfurrow.com>
Date: Tue, 17 Jun 2014 23:22:28 +0200
Subject: [PATCH] Fixes #37.

---
 CHANGELOG.md                    | 4 ++++
 Demo/DemoTests/NAMapViewTests.m | 4 ++++
 NAMapKit/NAMapView.m            | 3 +++
 3 files changed, 11 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 498dd12..0f9afe9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+### Next
+
+* [#37](https://github.com/neilang/NAMapKit/issues/37) - Added assert inside NAMapView#zoomRelativePoint when returning `{NaN, NaN}` - [@ashfurrow](http://github.com/ashfurrow).
+
 #### [3.1.1](https://github.com/neilang/NAMapKit/tree/v3.1.1) (5/12/2014)
 
 * [#31](https://github.com/neilang/NAMapKit/issues/31) - Fix: `NAPinAnnotation` and `NAPinAnnotationView` retain cycle - [@dblock](https://github.com/dblock).
diff --git a/Demo/DemoTests/NAMapViewTests.m b/Demo/DemoTests/NAMapViewTests.m
index d58fdae..37cbdc2 100644
--- a/Demo/DemoTests/NAMapViewTests.m
+++ b/Demo/DemoTests/NAMapViewTests.m
@@ -19,6 +19,10 @@
         expect(mapView).toNot.beNil();
         expect(mapView).to.beKindOf([NAMapView class]);
     });
+    
+    it(@"asserts on zoomRelativePoint: with a zero content size", ^{
+        expect(^{[mapView zoomRelativePoint:CGPointZero];}).to.raise(@"NSInternalInconsistencyException");
+    });
 });
 
 SpecEnd
diff --git a/NAMapKit/NAMapView.m b/NAMapKit/NAMapView.m
index a31feed..3069eda 100644
--- a/NAMapKit/NAMapView.m
+++ b/NAMapKit/NAMapView.m
@@ -121,6 +121,9 @@ - (void)centerOnPoint:(CGPoint)point animated:(BOOL)animate
 
 - (CGPoint)zoomRelativePoint:(CGPoint)point
 {
+    BOOL hasContentSize = fabsf(self.originalSize.width) > 0 && fabsf(self.originalSize.height) > 0;
+    NSAssert(hasContentSize, @"originalSize dimension is zero, will result in NaN in returned value.");
+    
     CGFloat x = (self.contentSize.width / self.originalSize.width) * point.x;
     CGFloat y = (self.contentSize.height / self.originalSize.height) * point.y;
     return CGPointMake(round(x), round(y));