[core] Fix screen coordinates when crossing the antimeridian (#2)

Added missing case. Really fixes #4155 this time.

3 files changed, 18 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index cb3dbd76e0..58a2fbd095 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -52,7 +52,7 @@ Known issues:
 ## iOS master
 
 - Offline packs can now be downloaded to allow users to view specific regions of the map offline. A new MGLOfflineStorage class provides APIs for managing MGLOfflinePacks. ([#4221](https://github.com/mapbox/mapbox-gl-native/pull/4221))
-- Fixed screen coordinates for LatLng coordinates accross the antimeridian. ([#4215](https://github.com/mapbox/mapbox-gl-native/issues/4155))
+- Fixed screen coordinates for LatLng coordinates accross the antimeridian. ([#4155](https://github.com/mapbox/mapbox-gl-native/issues/4155))
 - Fixed a bounce-back effect when panning the map. ([#4214](https://github.com/mapbox/mapbox-gl-native/pull/4214))
 - An icon laid out along a line no longer appears if it would extend past the end of the line. Some one-way arrows no longer point the wrong way. ([#3839](https://github.com/mapbox/mapbox-gl-native/pull/3839))
 - Reduce slanted segments in dashed lines near corners. ([#3914](https://github.com/mapbox/mapbox-gl-native/pull/3914))
diff --git a/src/mbgl/map/transform.cpp b/src/mbgl/map/transform.cpp
index d3cd30a627..a63c25faed 100644
--- a/src/mbgl/map/transform.cpp
+++ b/src/mbgl/map/transform.cpp
@@ -667,7 +667,7 @@ ScreenCoordinate Transform::latLngToScreenCoordinate(const LatLng& latLng) const
     // to the center side.
     double longitude = latLng.longitude;
     const double centerLng = getLatLng().longitude;
-    if (centerLng - latLng.longitude > util::LONGITUDE_MAX) {
+    if (std::abs(centerLng - latLng.longitude) > std::abs(util::LONGITUDE_MAX)) {
         if (centerLng > 0 && latLng.longitude < 0) {
             longitude += util::DEGREES_MAX;
         } else if (centerLng < 0 && latLng.longitude > 0) {
diff --git a/test/map/transform.cpp b/test/map/transform.cpp
index 6b9e960fe6..b7cf6e0a2c 100644
--- a/test/map/transform.cpp
+++ b/test/map/transform.cpp
@@ -318,4 +318,20 @@ TEST(Transform, Antimeridian) {
     ScreenCoordinate pixelSFForwards = transform.latLngToScreenCoordinate(coordinateSanFrancisco);
     ASSERT_DOUBLE_EQ(pixelSFBackwards.x, pixelSFForwards.x);
     ASSERT_DOUBLE_EQ(pixelSFBackwards.y, pixelSFForwards.y);
+
+    const LatLng coordinateWaikiri{ -16.9310, 179.9787 };
+    transform.setLatLngZoom(coordinateWaikiri, 10);
+    ScreenCoordinate pixelWaikiri = transform.latLngToScreenCoordinate(coordinateWaikiri);
+    ASSERT_DOUBLE_EQ(500.00000000007759, pixelWaikiri.x);
+    ASSERT_DOUBLE_EQ(500, pixelWaikiri.y);
+
+    transform.setLatLng({ coordinateWaikiri.latitude, 180.0213 });
+    ScreenCoordinate pixelWaikiriForwards = transform.latLngToScreenCoordinate(coordinateWaikiri);
+    ASSERT_DOUBLE_EQ(437.95953728819512, pixelWaikiriForwards.x);
+    ASSERT_DOUBLE_EQ(pixelWaikiri.y, pixelWaikiriForwards.y);
+
+    transform.setLatLng({ coordinateWaikiri.latitude, -179.9787 });
+    ScreenCoordinate pixelWaikiriBackwards = transform.latLngToScreenCoordinate(coordinateWaikiri);
+    ASSERT_DOUBLE_EQ(pixelWaikiriForwards.x, pixelWaikiriBackwards.x);
+    ASSERT_DOUBLE_EQ(pixelWaikiriForwards.y, pixelWaikiriBackwards.y);
 }