[ios] Fix pinch drift ignoring delegate camera change response

platform/ios/CHANGELOG.md

@@ -4,6 +4,7 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 
 ## 3.7.6
 
+* Fixed an issue where the pinch gesture could drift beyond bounds imposed by `-[MGLMapViewDelegate mapView:shouldChangeFromCamera:toCamera:]`. ([#11423](https://github.com/mapbox/mapbox-gl-native/pull/11423))
 * Improved the visibility of the heading indicator arrow. ([#11337](https://github.com/mapbox/mapbox-gl-native/pull/11337))
 
 ## 3.7.5 - February 16, 2018

platform/ios/app/MBXViewController.m

@@ -18,6 +18,11 @@
     { .latitude = -13.15589555, .longitude = -74.2178961777998 },
 };
 
+static const MGLCoordinateBounds colorado = {
+    .sw = { .latitude = 36.986207, .longitude = -109.049896},
+    .ne = { .latitude = 40.989329, .longitude = -102.062592},
+};
+
 static NSString * const MBXViewControllerAnnotationViewReuseIdentifer = @"MBXViewControllerAnnotationViewReuseIdentifer";
 
 typedef NS_ENUM(NSInteger, MBXSettingsSections) {
@@ -85,6 +90,7 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
     MBXSettingsMiscellaneousToggleTwoMaps,
     MBXSettingsMiscellaneousCountryLabels,
     MBXSettingsMiscellaneousShowSnapshots,
+    MBXSettingsMiscellaneousShouldLimitCameraChanges,
     MBXSettingsMiscellaneousPrintLogFile,
     MBXSettingsMiscellaneousDeleteLogFile,
 };
@@ -122,6 +128,7 @@ @interface MBXViewController () <UITableViewDelegate,
 @property (nonatomic) BOOL usingLocaleBasedCountryLabels;
 @property (nonatomic) BOOL reuseQueueStatsEnabled;
 @property (nonatomic) BOOL showZoomLevelEnabled;
+@property (nonatomic) BOOL shouldLimitCameraChanges;
 
 @end
 
@@ -363,7 +370,8 @@ - (void)dismissSettings:(__unused id)sender
                 @"Embedded Map View",
                 [NSString stringWithFormat:@"%@ Second Map", ([self.view viewWithTag:2] == nil ? @"Show" : @"Hide")],
                 [NSString stringWithFormat:@"Show Labels in %@", (_usingLocaleBasedCountryLabels ? @"Default Language" : [[NSLocale currentLocale] displayNameForKey:NSLocaleIdentifier value:[self bestLanguageForUser]])],
-                @"Show Snapshots"
+                @"Show Snapshots",
+                [NSString stringWithFormat:@"%@ Camera Changes", (_shouldLimitCameraChanges ? @"Unlimit" : @"Limit")],
             ]];
 
             if (self.debugLoggingEnabled)
@@ -652,6 +660,14 @@ - (void)performActionForSettingAtIndexPath:(NSIndexPath *)indexPath
                     [self performSegueWithIdentifier:@"ShowSnapshots" sender:nil];
                     break;
                 }
+                case MBXSettingsMiscellaneousShouldLimitCameraChanges:
+                {
+                    self.shouldLimitCameraChanges = !self.shouldLimitCameraChanges;
+                    if (self.shouldLimitCameraChanges) {
+                        [self.mapView setCenterCoordinate:CLLocationCoordinate2DMake(39.748947, -104.995882) zoomLevel:10 direction:0 animated:NO];
+                    }
+                    break;
+                }
                 default:
                     NSAssert(NO, @"All miscellaneous setting rows should be implemented");
                     break;
@@ -1880,6 +1896,31 @@ - (void)mapView:(MGLMapView *)mapView didFinishLoadingStyle:(MGLStyle *)style
     _usingLocaleBasedCountryLabels = [[self bestLanguageForUser] isEqualToString:@"en"];
 }
 
+- (BOOL)mapView:(MGLMapView *)mapView shouldChangeFromCamera:(MGLMapCamera *)oldCamera toCamera:(MGLMapCamera *)newCamera {
+    if (_shouldLimitCameraChanges) {
+        // Get the current camera to restore it after.
+        MGLMapCamera *currentCamera = mapView.camera;
+
+        // From the new camera obtain the center to test if it’s inside the boundaries.
+        CLLocationCoordinate2D newCameraCenter = newCamera.centerCoordinate;
+
+        // Set the map’s visible bounds to newCamera.
+        mapView.camera = newCamera;
+        MGLCoordinateBounds newVisibleCoordinates = mapView.visibleCoordinateBounds;
+
+        // Revert the camera.
+        mapView.camera = currentCamera;
+
+        // Test if the newCameraCenter and newVisibleCoordinates are inside Colorado.
+        BOOL inside = MGLCoordinateInCoordinateBounds(newCameraCenter, colorado);
+        BOOL intersects = MGLCoordinateInCoordinateBounds(newVisibleCoordinates.ne, colorado) && MGLCoordinateInCoordinateBounds(newVisibleCoordinates.sw, colorado);
+
+        return inside && intersects;
+    } else {
+        return YES;
+    }
+}
+
 - (void)mapViewRegionIsChanging:(MGLMapView *)mapView
 {
     [self updateHUD];

platform/ios/src/MGLMapView.mm

@@ -1459,10 +1459,12 @@ - (void)handlePinchGesture:(UIPinchGestureRecognizer *)pinch
         double zoom = log2(newScale);
         MGLMapCamera *toCamera = [self cameraByZoomingToZoomLevel:zoom aroundAnchorPoint:centerPoint];
 
-        if ([self _shouldChangeFromCamera:oldCamera toCamera:toCamera])
+        if ( ! [self _shouldChangeFromCamera:oldCamera toCamera:toCamera])
         {
             drift = NO;
-        } else {
+        }
+        else
+        {
             if (drift)
             {
                 _mbglMap->setZoom(zoom, mbgl::ScreenCoordinate { centerPoint.x, centerPoint.y }, MGLDurationFromTimeInterval(duration));
@@ -1695,7 +1697,9 @@ - (void)handleDoubleTapGesture:(UITapGestureRecognizer *)doubleTap
              {
                  [weakSelf unrotateIfNeededForGesture];
              }];
-        } else {
+        }
+        else
+        {
             [self unrotateIfNeededForGesture];
         }
     }