[ios] Improve user location annotation performance (#6019)

* [ios] Don't animate zoom-induced accuracy ring size changes

Improves perceived and actual performance by eliminating the implicit animation that occurred when the accuracy ring changed size during zooms. This previously would pile up animations as the zoom changed, causing an unsightly wobbling effect.

* [ios] Pre-calculate shadow paths for user dot and puck

Performance enhancement suggested by https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/CoreAnimation_guide/ImprovingAnimationPerformance/ImprovingAnimationPerformance.html

* [ios] Rasterize pulsating inner dot of user location annotation

Supposed performance enhancement and also improves edge smoothness.

1 files changed, 11 insertions, 1 deletions

diff --git a/platform/ios/src/MGLFaux3DUserLocationAnnotationView.m b/platform/ios/src/MGLFaux3DUserLocationAnnotationView.m
index ac0551430b..95a0084f9f 100644
--- a/platform/ios/src/MGLFaux3DUserLocationAnnotationView.m
+++ b/platform/ios/src/MGLFaux3DUserLocationAnnotationView.m
@@ -148,6 +148,7 @@ const CGFloat MGLUserLocationAnnotationArrowSize = MGLUserLocationAnnotationPuck
         _puckDot.backgroundColor = [[UIColor whiteColor] CGColor];
         _puckDot.shadowColor = [[UIColor blackColor] CGColor];
         _puckDot.shadowOpacity = 0.25;
+        _puckDot.shadowPath = [[UIBezierPath bezierPathWithOvalInRect:_puckDot.bounds] CGPath];
 
         if (self.mapView.camera.pitch)
         {
@@ -291,6 +292,13 @@ const CGFloat MGLUserLocationAnnotationArrowSize = MGLUserLocationAnnotationPuck
         if (accuracyRingSize > MGLUserLocationAnnotationDotSize + 15)
         {
             _accuracyRingLayer.hidden = NO;
+
+            // disable implicit animation of the accuracy ring, unless triggered by a change in accuracy
+            id shouldDisableActions = (_oldHorizontalAccuracy == self.userLocation.location.horizontalAccuracy) ? (id)kCFBooleanTrue : (id)kCFBooleanFalse;
+
+            [CATransaction begin];
+            [CATransaction setValue:shouldDisableActions forKey:kCATransactionDisableActions];
+
             _accuracyRingLayer.bounds = CGRectMake(0, 0, accuracyRingSize, accuracyRingSize);
             _accuracyRingLayer.cornerRadius = accuracyRingSize / 2;
 
@@ -298,6 +306,8 @@ const CGFloat MGLUserLocationAnnotationArrowSize = MGLUserLocationAnnotationPuck
             _haloLayer.bounds = _accuracyRingLayer.bounds;
             _haloLayer.cornerRadius = _accuracyRingLayer.cornerRadius;
             _haloLayer.shouldRasterize = NO;
+
+            [CATransaction commit];
         }
         else
         {
@@ -365,6 +375,7 @@ const CGFloat MGLUserLocationAnnotationArrowSize = MGLUserLocationAnnotationPuck
         _dotBorderLayer.backgroundColor = [[UIColor whiteColor] CGColor];
         _dotBorderLayer.shadowColor = [[UIColor blackColor] CGColor];
         _dotBorderLayer.shadowOpacity = 0.25;
+        _dotBorderLayer.shadowPath = [[UIBezierPath bezierPathWithOvalInRect:_dotBorderLayer.bounds] CGPath];
 
         if (self.mapView.camera.pitch)
         {
@@ -385,7 +396,6 @@ const CGFloat MGLUserLocationAnnotationArrowSize = MGLUserLocationAnnotationPuck
     {
         _dotLayer = [self circleLayerWithSize:MGLUserLocationAnnotationDotSize * 0.75];
         _dotLayer.backgroundColor = [self.mapView.tintColor CGColor];
-        _dotLayer.shouldRasterize = NO;
 
         // set defaults for the animations
         CAAnimationGroup *animationGroup = [self loopingAnimationGroupWithDuration:1.5];