[core] Added ConstrainMode::{HeightOnly,WidthAndHeight}

ConstrainMode gives flexibility to our engine to choose between
constraining both vertically and horizontally, or just vertically
(default behavior).

Constrain in both axis means we can no longer pan the map beyond the map
boundaries. This fixes an issue where e.g. annotations disappear upon
crossing the map boundaries.

2 files changed, 9 insertions, 1 deletions

diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index f2e605141b..c190088088 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -45,7 +45,8 @@ class Map : private util::noncopyable {
 public:
     explicit Map(View&, FileSource&,
                  MapMode mapMode = MapMode::Continuous,
-                 GLContextMode contextMode = GLContextMode::Unique);
+                 GLContextMode contextMode = GLContextMode::Unique,
+                 ConstrainMode constrainMode = ConstrainMode::HeightOnly);
     ~Map();
 
     // Pauses the render thread. The render thread will stop running but will not be terminated and will not lose state until resumed.
diff --git a/include/mbgl/map/mode.hpp b/include/mbgl/map/mode.hpp
index 6ad9af5c74..8b65baf99f 100644
--- a/include/mbgl/map/mode.hpp
+++ b/include/mbgl/map/mode.hpp
@@ -19,6 +19,13 @@ enum class GLContextMode : uint8_t {
     Shared,
 };
 
+// We can choose to constrain the map both horizontally or vertically, or only
+// vertically e.g. while panning.
+enum class ConstrainMode : uint8_t {
+    HeightOnly,
+    WidthAndHeight,
+};
+
 } // namespace mbgl
 
 #endif // MBGL_MAP_MODE