From e690e7cf1e91ba33017575ed9d068f2f38acab03 Mon Sep 17 00:00:00 2001
From: Jason Wray <jason@mapbox.com>
Date: Thu, 8 Mar 2018 14:52:43 -0500
Subject: [ios] Add camera limit debug option to iosapp

Adapted from https://github.com/mapbox/ios-sdk-examples/blob/cdff47276d261d58c7eb2d0ba75d9cce6c308417/Examples/ObjectiveC/BlockingGesturesDelegateExample.m
---
 platform/ios/app/MBXViewController.m | 43 +++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/platform/ios/app/MBXViewController.m b/platform/ios/app/MBXViewController.m
index 1046644f8c..63b06af583 100644
--- a/platform/ios/app/MBXViewController.m
+++ b/platform/ios/app/MBXViewController.m
@@ -18,6 +18,11 @@ static const CLLocationCoordinate2D WorldTourDestinations[] = {
     { .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 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
 @property (nonatomic) BOOL usingLocaleBasedCountryLabels;
 @property (nonatomic) BOOL reuseQueueStatsEnabled;
 @property (nonatomic) BOOL showZoomLevelEnabled;
+@property (nonatomic) BOOL shouldLimitCameraChanges;
 
 @end
 
@@ -363,7 +370,8 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
                 @"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 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
                     [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 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
     _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];
-- 
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