[ios] Move scale bar content size invalidation to map view

2 files changed, 8 insertions, 3 deletions

diff --git a/platform/ios/src/MGLMapView.mm b/platform/ios/src/MGLMapView.mm
index 0e76c0c71c..2bb46a3638 100644
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -1015,6 +1015,14 @@ public:
 // This gets called when the view dimension changes, e.g. because the device is being rotated.
 - (void)layoutSubviews
 {
+    // Calling this here instead of in the scale bar itself because if this is done in the
+    // scale bar instance, it triggers a call to this this `layoutSubviews` method that
+    // calls `_mbglMap->setSize()` just below that triggers rendering update which triggers
+    // another scale bar update which causes a rendering update loop and a major performace
+    // degradation. The only time the scale bar's intrinsic content size _must_ invalidated
+    // is here as a reaction to this object's view dimension changes.
+    [self.scaleBar invalidateIntrinsicContentSize];
+    
     [super layoutSubviews];
 
     [self adjustContentInset];
diff --git a/platform/ios/src/MGLScaleBar.mm b/platform/ios/src/MGLScaleBar.mm
index 410aa7d57e..966555e46a 100644
--- a/platform/ios/src/MGLScaleBar.mm
+++ b/platform/ios/src/MGLScaleBar.mm
@@ -225,9 +225,6 @@ static const CGFloat MGLFeetPerMeter = 3.28084;
                             CGRectGetMinY(self.frame),
                             size.width,
                             size.height);
-    
-    [self invalidateIntrinsicContentSize];
-    [self setNeedsLayout];
 }
 
 - (void)updateVisibility {