[android][core] Add `Map::latLngBoundsForCameraUnwrapped` and jni binding for `getVisibleCoordinateBounds`. (#16069)

* [android] Add getVisibleCoordinateBounds method.
* Fix Map::latLngBoundsForCamera, add Android binding for getVisibleRegionBounds.
* Add unit tests for CameraToLatLngBoundsWithRotation and CameraToLatLngBoundsCrossDateLine.
* Move API breaking changes to a new method name latLngBoundsForCameraUnwrapped.

5 files changed, 87 insertions, 0 deletions

diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index a3794962c6..62bb39e8c2 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -72,6 +72,7 @@ public:
     CameraOptions cameraForLatLngs(const std::vector<LatLng>&, const EdgeInsets&, optional<double> bearing = {}, optional<double> pitch = {}) const;
     CameraOptions cameraForGeometry(const Geometry<double>&, const EdgeInsets&, optional<double> bearing = {}, optional<double> pitch = {}) const;
     LatLngBounds latLngBoundsForCamera(const CameraOptions&) const;
+    LatLngBounds latLngBoundsForCameraUnwrapped(const CameraOptions&) const;
 
     /// @name Bounds
     /// @{
diff --git a/platform/android/src/native_map_view.cpp b/platform/android/src/native_map_view.cpp
index 554a59de76..d7351c7677 100644
--- a/platform/android/src/native_map_view.cpp
+++ b/platform/android/src/native_map_view.cpp
@@ -529,6 +529,26 @@ void NativeMapView::setVisibleCoordinateBounds(JNIEnv& env, const jni::Array<jni
     map->easeTo(cameraOptions, animationOptions);
 }
 
+void NativeMapView::getVisibleCoordinateBounds(JNIEnv& env, jni::Array<jdouble>& output) {
+    auto latlngBounds = map->latLngBoundsForCameraUnwrapped(map->getCameraOptions(mbgl::nullopt));
+
+    double latNorth = latlngBounds.north();
+    double lonEast = latlngBounds.east();
+    double latSouth = latlngBounds.south();
+    double lonWest = latlngBounds.west();
+
+    std::vector<jdouble> buffer;
+    buffer.reserve(4);
+
+    // Order of the LatLngBounds: double latNorth, double lonEast, double latSouth, double lonWest
+    buffer.push_back(latNorth);
+    buffer.push_back(lonEast);
+    buffer.push_back(latSouth);
+    buffer.push_back(lonWest);
+
+    output.SetRegion<std::vector<jdouble>>(env, 0, buffer);
+}
+
 void NativeMapView::scheduleSnapshot(jni::JNIEnv&) {
     mapRenderer.requestSnapshot([&](PremultipliedImage image) {
         auto _env = android::AttachEnv();
@@ -1172,6 +1192,7 @@ void NativeMapView::registerNative(jni::JNIEnv& env) {
         METHOD(&NativeMapView::projectedMetersForLatLng, "nativeProjectedMetersForLatLng"),
         METHOD(&NativeMapView::pixelForLatLng, "nativePixelForLatLng"),
         METHOD(&NativeMapView::pixelsForLatLngs, "nativePixelsForLatLngs"),
+        METHOD(&NativeMapView::getVisibleCoordinateBounds, "nativeGetVisibleCoordinateBounds"),
         METHOD(&NativeMapView::latLngForProjectedMeters, "nativeLatLngForProjectedMeters"),
         METHOD(&NativeMapView::latLngForPixel, "nativeLatLngForPixel"),
         METHOD(&NativeMapView::latLngsForPixels, "nativeLatLngsForPixels"),
diff --git a/platform/android/src/native_map_view.hpp b/platform/android/src/native_map_view.hpp
index 622c454b7d..ab93fab81f 100755..100644
--- a/platform/android/src/native_map_view.hpp
+++ b/platform/android/src/native_map_view.hpp
@@ -139,6 +139,8 @@ public:
 
     void setVisibleCoordinateBounds(JNIEnv&, const jni::Array<jni::Object<LatLng>>&, const jni::Object<RectF>&, jni::jdouble, jni::jlong);
 
+    void getVisibleCoordinateBounds(JNIEnv& env, jni::Array<jdouble>& output);
+
     void scheduleSnapshot(jni::JNIEnv&);
 
     jni::Local<jni::Object<CameraPosition>> getCameraPosition(jni::JNIEnv&);
diff --git a/src/mbgl/map/map.cpp b/src/mbgl/map/map.cpp
index 9cd9fdc15f..a994af305f 100644
--- a/src/mbgl/map/map.cpp
+++ b/src/mbgl/map/map.cpp
@@ -256,6 +256,27 @@ LatLngBounds Map::latLngBoundsForCamera(const CameraOptions& camera) const {
     );
 }
 
+LatLngBounds Map::latLngBoundsForCameraUnwrapped(const CameraOptions& camera) const {
+    Transform shallow{impl->transform.getState()};
+    Size size = shallow.getState().getSize();
+
+    shallow.jumpTo(camera);
+    LatLng nw = shallow.screenCoordinateToLatLng({});
+    LatLng se = shallow.screenCoordinateToLatLng({double(size.width), double(size.height)});
+    LatLng ne = shallow.screenCoordinateToLatLng({double(size.width), 0.0});
+    LatLng sw = shallow.screenCoordinateToLatLng({0.0, double(size.height)});
+    LatLng center = shallow.screenCoordinateToLatLng({double(size.width) / 2, double(size.height) / 2});
+    nw.unwrapForShortestPath(center);
+    se.unwrapForShortestPath(center);
+    ne.unwrapForShortestPath(center);
+    sw.unwrapForShortestPath(center);
+    LatLngBounds bounds = LatLngBounds::hull(nw, se);
+    bounds.extend(ne);
+    bounds.extend(sw);
+    bounds.extend(center);
+    return bounds;
+}
+
 #pragma mark - Bounds
 
 void Map::setBounds(const BoundOptions& options) {
diff --git a/test/map/map.test.cpp b/test/map/map.test.cpp
index 31cc85619e..a0cd64bdd5 100644
--- a/test/map/map.test.cpp
+++ b/test/map/map.test.cpp
@@ -252,6 +252,48 @@ TEST(Map, CameraToLatLngBounds) {
     ASSERT_NEAR(camera.center->longitude(), virtualCamera.center->longitude(), 1e-7);
 }
 
+TEST(Map, CameraToLatLngBoundsUnwrappedWithRotation) {
+    MapTest<> test;
+
+    test.map.jumpTo(CameraOptions().withCenter(LatLng{45, 90}).withZoom(16.0).withBearing(45.0));
+
+    const Size size = test.map.getMapOptions().size();
+
+    CameraOptions camera = test.map.getCameraOptions();
+
+    ASSERT_TRUE(test.map.latLngBoundsForCameraUnwrapped(camera).contains(test.map.latLngForPixel({})));
+    ASSERT_TRUE(
+        test.map.latLngBoundsForCameraUnwrapped(camera).contains(test.map.latLngForPixel({0.0, double(size.height)})));
+    ASSERT_TRUE(
+        test.map.latLngBoundsForCameraUnwrapped(camera).contains(test.map.latLngForPixel({double(size.width), 0.0})));
+    ASSERT_TRUE(test.map.latLngBoundsForCameraUnwrapped(camera).contains(
+        test.map.latLngForPixel({double(size.width), double(size.height)})));
+    ASSERT_TRUE(test.map.latLngBoundsForCameraUnwrapped(camera).contains(
+        test.map.latLngForPixel({double(size.width) / 2, double(size.height) / 2})));
+}
+
+TEST(Map, CameraToLatLngBoundsUnwrappedCrossDateLine) {
+    MapTest<> test;
+
+    test.map.jumpTo(CameraOptions().withCenter(LatLng{0, 180}).withZoom(16.0));
+
+    const Size size = test.map.getMapOptions().size();
+
+    CameraOptions camera = test.map.getCameraOptions();
+
+    ASSERT_TRUE(test.map.latLngBoundsForCameraUnwrapped(camera).contains(test.map.latLngForPixel({}), LatLng::Wrapped));
+    ASSERT_TRUE(test.map.latLngBoundsForCameraUnwrapped(camera).contains(
+        test.map.latLngForPixel({0.0, double(size.height)}), LatLng::Wrapped));
+    ASSERT_TRUE(test.map.latLngBoundsForCameraUnwrapped(camera).contains(
+        test.map.latLngForPixel({double(size.width), 0.0}), LatLng::Wrapped));
+    ASSERT_TRUE(test.map.latLngBoundsForCameraUnwrapped(camera).contains(
+        test.map.latLngForPixel({double(size.width), double(size.height)}), LatLng::Wrapped));
+    ASSERT_TRUE(test.map.latLngBoundsForCameraUnwrapped(camera).contains(
+        test.map.latLngForPixel({double(size.width) / 2, double(size.height) / 2})));
+
+    ASSERT_TRUE(test.map.latLngBoundsForCameraUnwrapped(camera).crossesAntimeridian());
+}
+
 TEST(Map, Offline) {
     MapTest<DefaultFileSource> test {":memory:", "."};