Rendering statistics view (#3322)

Co-authored-by: Bart Louwers <bart@emeel.net>

platform/ios/src/MLNMapView+Impl.h

@@ -64,7 +64,7 @@ class MLNMapViewImpl : public mbgl::MapObserver {
   void onDidFinishLoadingMap() override;
   void onDidFailLoadingMap(mbgl::MapLoadError mapError, const std::string& what) override;
   void onWillStartRenderingFrame() override;
-  void onDidFinishRenderingFrame(mbgl::MapObserver::RenderFrameStatus) override;
+  void onDidFinishRenderingFrame(const mbgl::MapObserver::RenderFrameStatus&) override;
   void onWillStartRenderingMap() override;
   void onDidFinishRenderingMap(mbgl::MapObserver::RenderMode) override;
   void onDidFinishLoadingStyle() override;

platform/ios/src/MLNMapView+Impl.mm

@@ -79,9 +79,9 @@ void MLNMapViewImpl::onWillStartRenderingFrame() {
     [mapView mapViewWillStartRenderingFrame];
 }
 
-void MLNMapViewImpl::onDidFinishRenderingFrame(mbgl::MapObserver::RenderFrameStatus status) {
-    bool fullyRendered = status.mode == mbgl::MapObserver::RenderMode::Full;
-    [mapView mapViewDidFinishRenderingFrameFullyRendered:fullyRendered frameEncodingTime:status.frameEncodingTime frameRenderingTime:status.frameRenderingTime];
+void MLNMapViewImpl::onDidFinishRenderingFrame(const mbgl::MapObserver::RenderFrameStatus& status) {
+    const bool fullyRendered = status.mode == mbgl::MapObserver::RenderMode::Full;
+    [mapView mapViewDidFinishRenderingFrameFullyRendered:fullyRendered renderingStats:status.renderingStats];
 }
 
 void MLNMapViewImpl::onWillStartRenderingMap() {

platform/ios/src/MLNMapView.h

@@ -2157,6 +2157,16 @@ vertically on the map.
  */
 @property (nonatomic) MLNMapDebugMaskOptions debugMask;
 
+/**
+ Returns the status of the rendering statistics overlay.
+ */
+- (BOOL)isRenderingStatsViewEnabled;
+
+/**
+ Enable a rendering statistics overlay with ``MLNRenderingStats`` values.
+ */
+- (void)enableRenderingStatsView:(BOOL)value;
+
 /**
  Get the list of action journal log files from oldest to newest.
 

platform/ios/src/MLNMapView.mm

@@ -68,6 +68,7 @@
 #import "MLNLoggingConfiguration_Private.h"
 #import "MLNNetworkConfiguration_Private.h"
 #import "MLNReachability.h"
+#import "MLNRenderingStats_Private.h"
 #import "MLNSettings_Private.h"
 #import "MLNActionJournalOptions_Private.h"
 #import "MLNMapProjection.h"
@@ -495,6 +496,8 @@ public:
     CFTimeInterval _frameCounterStartTime;
     NSInteger _frameCount;
     CFTimeInterval _frameDurations;
+
+    MLNRenderingStats* _renderingStats;
 }
 
 // MARK: - Setup & Teardown -
@@ -6913,8 +6916,7 @@ static void *windowScreenContext = &windowScreenContext;
 }
 
 - (void)mapViewDidFinishRenderingFrameFullyRendered:(BOOL)fullyRendered
-                                  frameEncodingTime:(double)frameEncodingTime
-                                 frameRenderingTime:(double)frameRenderingTime {
+                                     renderingStats:(const mbgl::gfx::RenderingStats &)stats {
     if (!_mbglMap)
     {
         return;
@@ -6926,9 +6928,21 @@ static void *windowScreenContext = &windowScreenContext;
         [self.style didChangeValueForKey:@"layers"];
     }
 
-    if ([self.delegate respondsToSelector:@selector(mapViewDidFinishRenderingFrame:fullyRendered:frameEncodingTime:frameRenderingTime:)])
+    if ([self.delegate respondsToSelector:@selector(mapViewDidFinishRenderingFrame:fullyRendered:renderingStats:)])
     {
-        [self.delegate mapViewDidFinishRenderingFrame:self fullyRendered:fullyRendered frameEncodingTime:frameEncodingTime frameRenderingTime:frameRenderingTime];
+        if (!_renderingStats) {
+            _renderingStats = [[MLNRenderingStats alloc] init];
+        }
+
+        [_renderingStats setCoreData:stats];
+        [self.delegate mapViewDidFinishRenderingFrame:self fullyRendered:fullyRendered renderingStats:_renderingStats];
+    }
+    else if ([self.delegate respondsToSelector:@selector(mapViewDidFinishRenderingFrame:fullyRendered:frameEncodingTime:frameRenderingTime:)])
+    {
+        [self.delegate mapViewDidFinishRenderingFrame:self
+                                        fullyRendered:fullyRendered
+                                    frameEncodingTime:stats.encodingTime
+                                   frameRenderingTime:stats.renderingTime];
     }
     else if ([self.delegate respondsToSelector:@selector(mapViewDidFinishRenderingFrame:fullyRendered:)])
     {
@@ -7557,6 +7571,14 @@ static void *windowScreenContext = &windowScreenContext;
     return _annotationViewReuseQueueByIdentifier[identifier];
 }
 
+- (BOOL)isRenderingStatsViewEnabled {
+    return _mbglMap->isRenderingStatsViewEnabled();
+}
+
+- (void)enableRenderingStatsView:(BOOL)value {
+    _mbglMap->enableRenderingStatsView(value);
+}
+
 - (void)triggerRepaint
 {
     _mbglMap->triggerRepaint();

platform/ios/src/MLNMapViewDelegate.h

@@ -1,6 +1,7 @@
 #import <UIKit/UIKit.h>
 
 #import "MLNCameraChangeReason.h"
+#import "MLNRenderingStats.h"
 #import "MLNTileOperation.h"
 #import "Mapbox.h"
 
@@ -267,6 +268,23 @@ NS_ASSUME_NONNULL_BEGIN
                          fullyRendered:(BOOL)fullyRendered
                      frameEncodingTime:(double)frameEncodingTime
                     frameRenderingTime:(double)frameRenderingTime;
+/**
+ Tells the delegate that the map view has just redrawn.
+
+ This method is called any time the map view needs to redraw due to a change in
+ the viewpoint or style property transition. This method may be called very
+ frequently, even moreso than `-mapViewRegionIsChanging:`. Therefore, your
+ implementation of this method should be as lightweight as possible to avoid
+ affecting performance.
+
+ @param mapView The map view that has just redrawn.
+ @param fullyRendered A Boolean value indicating whether the map is fully rendered or not.
+ @param renderingStats A collection of rendering statistics
+ */
+- (void)mapViewDidFinishRenderingFrame:(MLNMapView *)mapView
+                         fullyRendered:(BOOL)fullyRendered
+                        renderingStats:(MLNRenderingStats *)renderingStats;
+
 /**
  Tells the delegate that the map view is entering an idle state, and no more
  drawing will be necessary until new data is loaded or there is some interaction

platform/ios/src/MLNMapView_Private.h

@@ -3,11 +3,14 @@
 #import "MLNTileOperation.h"
 #import "MLNUserLocationAnnotationView.h"
 
-#include <mbgl/util/size.hpp>
-
 namespace mbgl {
 class Map;
 class Renderer;
+
+namespace gfx {
+struct RenderingStats;
+}
+
 }  // namespace mbgl
 
 class MLNMapViewImpl;
@@ -39,8 +42,7 @@ FOUNDATION_EXTERN MLN_EXPORT MLNExceptionName const _Nonnull MLNUnderlyingMapUna
 - (void)mapViewDidFailLoadingMapWithError:(nonnull NSError *)error;
 - (void)mapViewWillStartRenderingFrame;
 - (void)mapViewDidFinishRenderingFrameFullyRendered:(BOOL)fullyRendered
-                                  frameEncodingTime:(double)frameEncodingTime
-                                 frameRenderingTime:(double)frameRenderingTime;
+                                     renderingStats:(const mbgl::gfx::RenderingStats &)stats;
 - (void)mapViewWillStartRenderingMap;
 - (void)mapViewDidFinishRenderingMapFullyRendered:(BOOL)fullyRendered;
 - (void)mapViewDidBecomeIdle;