[core] Added padding option to CameraOptions

Moved EdgeInsets to geo.hpp so CameraOptions and Transform can refer to it. Added a padding option to CameraOptions that alters the frame of reference for the center option. Added optional padding parameters to LatLng getters and setters.

Working towards #2600.

3 files changed, 40 insertions, 8 deletions

diff --git a/include/mbgl/map/camera.hpp b/include/mbgl/map/camera.hpp
index 80734b76fd..32ad8f019f 100644
--- a/include/mbgl/map/camera.hpp
+++ b/include/mbgl/map/camera.hpp
@@ -17,6 +17,10 @@ struct CameraOptions {
     /** Coordinate at the center of the map. */
     mapbox::util::optional<LatLng> center;
     
+    /** Padding around the interior of the view that affects the frame of
+        reference for `center`. */
+    mapbox::util::optional<EdgeInsets> padding;
+    
     /** Point of reference for `zoom` and `angle`, assuming an origin at the
         top-left corner of the view. */
     mapbox::util::optional<PrecisionPoint> anchor;
diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index 3e52d57d19..3852bb7b6f 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -34,13 +34,6 @@ namespace util {
 template <class T> class Thread;
 } // namespace util
 
-struct EdgeInsets {
-    double top = 0;
-    double left = 0;
-    double bottom = 0;
-    double right = 0;
-};
-
 class Map : private util::noncopyable {
     friend class View;
 
@@ -106,8 +99,9 @@ public:
     // Position
     void moveBy(const PrecisionPoint&, const Duration& = Duration::zero());
     void setLatLng(const LatLng&, const PrecisionPoint&, const Duration& = Duration::zero());
+    void setLatLng(const LatLng&, const EdgeInsets&, const Duration& = Duration::zero());
     void setLatLng(const LatLng&, const Duration& = Duration::zero());
-    LatLng getLatLng() const;
+    LatLng getLatLng(const EdgeInsets& = {}) const;
     void resetPosition();
 
     // Scale
diff --git a/include/mbgl/util/geo.hpp b/include/mbgl/util/geo.hpp
index e815456f22..db7d9c792e 100644
--- a/include/mbgl/util/geo.hpp
+++ b/include/mbgl/util/geo.hpp
@@ -108,6 +108,40 @@ enum class NorthOrientation : uint8_t {
     Leftwards,
 };
 
+/// The distance on each side between a rectangle and a rectangle within.
+struct EdgeInsets {
+    double top = 0;     ///< Number of pixels inset from the top edge.
+    double left = 0;    ///< Number of pixels inset from the left edge.
+    double bottom = 0;  ///< Number of pixels inset from the bottom edge.
+    double right = 0;   ///< Number of pixels inset from the right edge.
+    
+    inline EdgeInsets() {}
+    
+    inline EdgeInsets(const double t, const double l, const double b, const double r)
+        : top(t), left(l), bottom(b), right(r) {}
+    
+    inline operator bool() const {
+        return top || left || bottom || right;
+    }
+    
+    inline void operator+=(const EdgeInsets& o) {
+        top += o.top;
+        left += o.left;
+        bottom += o.bottom;
+        right += o.right;
+    }
+
+    inline EdgeInsets operator+(const EdgeInsets& o) const {
+        return {
+            top + o.top, left + o.left, bottom + o.bottom, right + o.right,
+        };
+    }
+    
+    PrecisionPoint getCenter(uint16_t width, uint16_t height) const;
+    
+    void flip();
+};
+
 } // namespace mbgl
 
 #endif