[core] Remove optional from Map::setLatLngBounds()

This is a first step into grouping together bounds related Map methods
into one that takes a "BoundOptions" object. LatLngBounds::unbounded()
replaces an undefined optional<LatLngBounds>.

v2: Document LatLngBounds::unbounded()

2 files changed, 16 insertions, 3 deletions

diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index 0c979f3e19..93e5190f99 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -77,8 +77,8 @@ public:
     LatLngBounds latLngBoundsForCamera(const CameraOptions&) const;
 
     // Bounds
-    void setLatLngBounds(optional<LatLngBounds>);
-    optional<LatLngBounds> getLatLngBounds() const;
+    void setLatLngBounds(LatLngBounds);
+    LatLngBounds getLatLngBounds() const;
     void setMinZoom(double);
     double getMinZoom() const;
     void setMaxZoom(double);
diff --git a/include/mbgl/util/geo.hpp b/include/mbgl/util/geo.hpp
index 0943c64d5f..a9c1112fd1 100644
--- a/include/mbgl/util/geo.hpp
+++ b/include/mbgl/util/geo.hpp
@@ -105,6 +105,15 @@ public:
         return bounds;
     }
 
+    /// Returns an infinite bound, a bound for which the constrain method returns its
+    /// input unmodified.
+    ///
+    /// Note: this is different than LatLngBounds::world() since arbitrary unwrapped
+    /// coordinates are also inside the bounds.
+    static LatLngBounds unbounded() {
+        return {};
+    }
+
     // Constructs a LatLngBounds object with the tile's exact boundaries.
     LatLngBounds(const CanonicalTileID&);
 
@@ -159,15 +168,19 @@ public:
 private:
     LatLng sw;
     LatLng ne;
+    bool bounded = true;
 
     LatLngBounds(LatLng sw_, LatLng ne_)
         : sw(std::move(sw_)), ne(std::move(ne_)) {}
 
+    LatLngBounds()
+        : sw({-90, -180}), ne({90, 180}), bounded(false) {}
+
     bool containsLatitude(double latitude) const;
     bool containsLongitude(double longitude, LatLng::WrapMode wrap) const;
 
     friend bool operator==(const LatLngBounds& a, const LatLngBounds& b) {
-        return a.sw == b.sw && a.ne == b.ne;
+        return (!a.bounded && !b.bounded) || (a.bounded && b.bounded && a.sw == b.sw && a.ne == b.ne);
     }
 
     friend bool operator!=(const LatLngBounds& a, const LatLngBounds& b) {