[core] Add `cameraForLatLngs()` method with modified bearing

3 files changed, 39 insertions, 12 deletions

diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index 4108725776..3e1f090665 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -66,6 +66,11 @@ public:
     void jumpTo(const CameraOptions&);
     void easeTo(const CameraOptions&, const AnimationOptions&);
     void flyTo(const CameraOptions&, const AnimationOptions&);
+    CameraOptions cameraForLatLngBounds(const LatLngBounds&, const EdgeInsets&) const;
+    CameraOptions cameraForLatLngs(const std::vector<LatLng>&, const EdgeInsets&) const;
+    CameraOptions cameraForLatLngs(const std::vector<LatLng>&, double heading, const EdgeInsets&) const;
+
+    LatLngBounds latLngBoundsForCamera(const CameraOptions&) const;
 
     // Position
     void moveBy(const ScreenCoordinate&, const AnimationOptions& = {});
@@ -82,9 +87,6 @@ public:
     double getZoom() const;
     void setLatLngZoom(const LatLng&, double zoom, const AnimationOptions& = {});
     void setLatLngZoom(const LatLng&, double zoom, const EdgeInsets&, const AnimationOptions& = {});
-    CameraOptions cameraForLatLngBounds(const LatLngBounds&, const EdgeInsets&) const;
-    CameraOptions cameraForLatLngs(const std::vector<LatLng>&, const EdgeInsets&) const;
-    LatLngBounds latLngBoundsForCamera(const CameraOptions&) const;
     void resetZoom();
 
     // Bounds
diff --git a/src/mbgl/map/map.cpp b/src/mbgl/map/map.cpp
index 7534fe67ad..76ef4bc69f 100644
--- a/src/mbgl/map/map.cpp
+++ b/src/mbgl/map/map.cpp
@@ -373,18 +373,18 @@ CameraOptions Map::cameraForLatLngBounds(const LatLngBounds& bounds, const EdgeI
     }, padding);
 }
 
-CameraOptions Map::cameraForLatLngs(const std::vector<LatLng>& latLngs, const EdgeInsets& padding) const {
+CameraOptions cameraForLatLngs(const std::vector<LatLng>& latLngs, const Transform& transform, const EdgeInsets& padding) {
     CameraOptions options;
     if (latLngs.empty()) {
         return options;
     }
-
+    Size size = transform.getState().getSize();
     // Calculate the bounds of the possibly rotated shape with respect to the viewport.
     ScreenCoordinate nePixel = {-INFINITY, -INFINITY};
     ScreenCoordinate swPixel = {INFINITY, INFINITY};
-    double viewportHeight = getSize().height;
+    double viewportHeight = size.height;
     for (LatLng latLng : latLngs) {
-        ScreenCoordinate pixel = impl->transform.latLngToScreenCoordinate(latLng);
+        ScreenCoordinate pixel = transform.latLngToScreenCoordinate(latLng);
         swPixel.x = std::min(swPixel.x, pixel.x);
         nePixel.x = std::max(nePixel.x, pixel.x);
         swPixel.y = std::min(swPixel.y, viewportHeight - pixel.y);
@@ -396,14 +396,14 @@ CameraOptions Map::cameraForLatLngs(const std::vector<LatLng>& latLngs, const Ed
     // Calculate the zoom level.
     double minScale = INFINITY;
     if (width > 0 || height > 0) {
-        double scaleX = double(getSize().width) / width;
-        double scaleY = double(getSize().height) / height;
+        double scaleX = double(size.width) / width;
+        double scaleY = double(size.height) / height;
         scaleX -= (padding.left() + padding.right()) / width;
         scaleY -= (padding.top() + padding.bottom()) / height;
         minScale = util::min(scaleX, scaleY);
     }
-    double zoom = getZoom() + util::log2(minScale);
-    zoom = util::clamp(zoom, getMinZoom(), getMaxZoom());
+    double zoom = transform.getZoom() + util::log2(minScale);
+    zoom = util::clamp(zoom, transform.getState().getMinZoom(), transform.getState().getMaxZoom());
 
     // Calculate the center point of a virtual bounds that is extended in all directions by padding.
     ScreenCoordinate centerPixel = nePixel + swPixel;
@@ -421,11 +421,24 @@ CameraOptions Map::cameraForLatLngs(const std::vector<LatLng>& latLngs, const Ed
     // CameraOptions origin is at the top-left corner.
     centerPixel.y = viewportHeight - centerPixel.y;
 
-    options.center = latLngForPixel(centerPixel);
+    options.center = transform.screenCoordinateToLatLng(centerPixel);
     options.zoom = zoom;
     return options;
 }
 
+CameraOptions Map::cameraForLatLngs(const std::vector<LatLng>& latLngs, const EdgeInsets& padding) const {
+    return mbgl::cameraForLatLngs(latLngs, impl->transform, padding);
+}
+
+CameraOptions Map::cameraForLatLngs(const std::vector<LatLng>& latLngs, double heading, const EdgeInsets& padding) const {
+    double angle = -heading * util::DEG2RAD;
+    Transform transform(impl->transform.getState());
+    transform.setAngle(angle);
+    CameraOptions options = mbgl::cameraForLatLngs(latLngs, transform, padding);
+    options.angle = angle;
+    return options;
+}
+
 LatLngBounds Map::latLngBoundsForCamera(const CameraOptions& camera) const {
     Transform shallow { impl->transform.getState() };
     Size size = shallow.getState().getSize();
diff --git a/test/map/map.test.cpp b/test/map/map.test.cpp
index 50d5e50abb..a86711925a 100644
--- a/test/map/map.test.cpp
+++ b/test/map/map.test.cpp
@@ -111,6 +111,18 @@ TEST(Map, LatLngBoundsToCamera) {
     ASSERT_TRUE(bounds.contains(*virtualCamera.center));
 }
 
+TEST(Map, LatLngsToCamera) {
+    MapTest<> test;
+
+    std::vector<LatLng> latLngs{{ 40.712730, 74.005953 }, {15.68169,73.499857}, {30.82678, 83.4082}};
+
+    CameraOptions virtualCamera = test.map.cameraForLatLngs(latLngs, 23, {});
+    EXPECT_DOUBLE_EQ(virtualCamera.angle.value_or(0), -23 * util::DEG2RAD);
+    EXPECT_NEAR(virtualCamera.zoom.value_or(0), 2.75434, 1e-5);
+    EXPECT_NEAR(virtualCamera.center->latitude(), 28.49288, 1e-5);
+    EXPECT_NEAR(virtualCamera.center->longitude(), 74.97437, 1e-5);
+}
+
 TEST(Map, CameraToLatLngBounds) {
     MapTest<> test;