Refined -camera

Now within 1% of MKMapCamera output. -setCamera: still needs work. Also added -[MGLMapCamera description], which avoids the typographical faux pas found in `-[MKMapCamera description], of which I shall not speak.

3 files changed, 44 insertions, 10 deletions

diff --git a/ios/app/MBXViewController.mm b/ios/app/MBXViewController.mm
index 99c207d24d..19422cd9cf 100644
--- a/ios/app/MBXViewController.mm
+++ b/ios/app/MBXViewController.mm
@@ -138,11 +138,26 @@ mbgl::Settings_NSUserDefaults *settings = nullptr;
 {
     if (buttonIndex == actionSheet.firstOtherButtonIndex)
     {
-        [self.mapView resetNorth];
+//        [self.mapView resetNorth];
+//        [self.mapView setCenterCoordinate:CLLocationCoordinate2DMake(29.95, -90.066667) zoomLevel:14 direction:90 animated:YES];
+        CLLocationCoordinate2D coordinates[] = {
+            CLLocationCoordinate2DMake(37, -109+2/60+48/(60*60)),
+            CLLocationCoordinate2DMake(37, -102.05),
+            CLLocationCoordinate2DMake(41, -102.05),
+            CLLocationCoordinate2DMake(41, -109+2/60+48/(60*60)),
+        };
+        [self.mapView setVisibleCoordinates:coordinates count:4 edgePadding:UIEdgeInsetsMake(32, 0, 0, 0) animated:NO];
+//        self.mapView.camera = [MGLMapCamera cameraLookingAtCenterCoordinate:CLLocationCoordinate2DMake(29.95, -90.066667) fromDistance:1837212.607578 heading:90];
+        // 1982881.568373
+        NSLog(@"Camera: %@", self.mapView.camera);
+        NSLog(@"Altitude: %f", self.mapView.camera.altitude);
     }
     else if (buttonIndex == actionSheet.firstOtherButtonIndex + 1)
     {
-        [self.mapView resetPosition];
+//        [self.mapView resetPosition];
+        MGLMapCamera *camera = [self.mapView.camera copy];
+        camera.pitch = 45;
+        [self.mapView setCamera:camera animated:YES];
     }
     else if (buttonIndex == actionSheet.firstOtherButtonIndex + 2)
     {
diff --git a/platform/ios/MGLMapCamera.mm b/platform/ios/MGLMapCamera.mm
index 6af747174d..c877e3ebb5 100644
--- a/platform/ios/MGLMapCamera.mm
+++ b/platform/ios/MGLMapCamera.mm
@@ -23,12 +23,12 @@
     
     mbgl::ProjectedMeters centerMeters = mbgl::Projection::projectedMetersForLatLng(centerLatLng);
     mbgl::ProjectedMeters eyeMeters = mbgl::Projection::projectedMetersForLatLng(eyeLatLng);
-    CLLocationDirection heading = std::tan((centerMeters.northing - eyeMeters.northing) /
-                                           (centerMeters.easting - eyeMeters.easting));
+    CLLocationDirection heading = std::atan((centerMeters.northing - eyeMeters.northing) /
+                                            (centerMeters.easting - eyeMeters.easting));
     
     double groundDistance = std::sqrt(std::pow(centerMeters.northing - eyeMeters.northing, 2) +
                                       std::pow(centerMeters.easting - eyeMeters.easting, 2));
-    CGFloat pitch = std::tan(eyeAltitude / groundDistance);
+    CGFloat pitch = std::atan(eyeAltitude / groundDistance);
     
     return [[self alloc] initWithCenterCoordinate:centerCoordinate
                                          altitude:eyeAltitude
@@ -92,4 +92,10 @@
                                                                heading:_heading];
 }
 
+- (NSString *)description
+{
+    return [NSString stringWithFormat:@"<MKMapCamera %p centerCoordinate:%f, %f altitude:%.0fm heading:%.0f° pitch:%.0f°>",
+            self, _centerCoordinate.latitude, _centerCoordinate.longitude, _altitude, _heading, _pitch];
+}
+
 @end
diff --git a/platform/ios/MGLMapView.mm b/platform/ios/MGLMapView.mm
index 055db6ef81..10501d9840 100644
--- a/platform/ios/MGLMapView.mm
+++ b/platform/ios/MGLMapView.mm
@@ -48,6 +48,7 @@ NSUInteger const MGLStyleVersion = 8;
 const NSTimeInterval MGLAnimationDuration = 0.3;
 const CGSize MGLAnnotationUpdateViewportOutset = {150, 150};
 const CGFloat MGLMinimumZoom = 3;
+const CLLocationDegrees MGLAngularFieldOfView = M_PI / 6;
 
 NSString *const MGLAnnotationIDKey = @"MGLAnnotationIDKey";
 NSString *const MGLAnnotationSymbolKey = @"MGLAnnotationSymbolKey";
@@ -1756,9 +1757,15 @@ mbgl::LatLngBounds MGLLatLngBoundsFromCoordinateBounds(MGLCoordinateBounds coord
 
 - (MGLMapCamera *)camera
 {
-    CLLocationDistance altitude = 6.53e7 * exp(-0.6931 * self.zoomLevel);
-//  landscape: CLLocationDistance altitude = 1.092e7 * exp(-0.6931 * self.zoomLevel);
+    mbgl::ProjectedMeters neMeters = _mbglMap->projectedMetersForLatLng(self.viewportBounds.ne);
+    mbgl::ProjectedMeters centerMeters = _mbglMap->projectedMetersForLatLng(_mbglMap->getLatLng());
+    CLLocationDistance longitudinalDistance = neMeters.easting - centerMeters.easting;
+    CLLocationDistance latitudinalDistance = neMeters.northing - centerMeters.northing;
+    CLLocationDistance distance = (latitudinalDistance + longitudinalDistance) / 2;
+    CLLocationDistance altitude = distance / std::tan(MGLAngularFieldOfView / 2);
+    
     CGFloat pitch = MGLDegreesFromRadians(_mbglMap->getPitch());
+    
     return [MGLMapCamera cameraLookingAtCenterCoordinate:self.centerCoordinate
                                             fromDistance:altitude
                                                    pitch:pitch
@@ -1772,9 +1779,15 @@ mbgl::LatLngBounds MGLLatLngBoundsFromCoordinateBounds(MGLCoordinateBounds coord
 
 - (void)setCamera:(MGLMapCamera *)camera animated:(BOOL)animated
 {
-    mbgl::CameraOptions options;
-    options.center = MGLLatLngFromLocationCoordinate2D(camera.centerCoordinate);
-    options.zoom = log(camera.altitude / 6.53e7) / -0.6931;
+    mbgl::LatLng center = MGLLatLngFromLocationCoordinate2D(camera.centerCoordinate);
+    mbgl::ProjectedMeters centerMeters = _mbglMap->projectedMetersForLatLng(center);
+    CLLocationDistance distance = camera.altitude * std::tan(MGLAngularFieldOfView / 2);
+    mbgl::LatLngBounds bounds = {
+        { centerMeters.northing - distance, centerMeters.easting - distance },
+        { centerMeters.northing + distance, centerMeters.easting + distance },
+    };
+    mbgl::CameraOptions options = _mbglMap->cameraForLatLngBounds(bounds, {});
+    
     options.angle = MGLRadiansFromDegrees(-camera.heading);
     options.pitch = MGLRadiansFromDegrees(camera.pitch);
     if (animated)