Fixes wrong map view dimension on CarPlay. (#3890)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

platform/darwin/bazel/files.bzl

@@ -63,6 +63,7 @@ MLN_DARWIN_OBJC_HEADERS = [
     "src/MLNCustomStyleLayer.h",
     "src/MLNCustomDrawableStyleLayer.h",
     "src/MLNDefaultStyle.h",
+    "src/MLNDisplayUtils.h",
     "src/MLNDistanceFormatter.h",
     "src/MLNFeature.h",
     "src/MLNForegroundStyleLayer.h",
@@ -175,6 +176,7 @@ MLN_DARWIN_PUBLIC_OBJCPP_SOURCE = [
     "src/MLNComputedShapeSource.mm",
     "src/MLNCustomStyleLayer.mm",
     "src/MLNDefaultStyle.mm",
+    "src/MLNDisplayUtils.mm",
     "src/MLNFeature.mm",
     "src/MLNForegroundStyleLayer.mm",
     "src/MLNFoundation.mm",

platform/darwin/src/MLNDisplayUtils.h

@@ -0,0 +1,10 @@
+#import <Foundation/Foundation.h>
+#import <TargetConditionals.h>
+
+#if TARGET_OS_IPHONE || TARGET_OS_TV
+#import <UIKit/UIKit.h>
+#else
+#import <AppKit/AppKit.h>
+#endif
+
+FOUNDATION_EXTERN CGFloat MLNEffectiveScaleFactorForView(id viewOrNil);

platform/darwin/src/MLNDisplayUtils.mm

@@ -0,0 +1,27 @@
+#import "MLNDisplayUtils.h"
+
+CGFloat MLNEffectiveScaleFactorForView(id viewOrNil) {
+#if TARGET_OS_IPHONE || TARGET_OS_TV
+
+    UIView *view = (UIView *)viewOrNil;
+    UIScreen *screen = view.window.screen ?: [UIScreen mainScreen];
+
+    CGFloat logicalToPixelRatio = screen.nativeBounds.size.width / screen.bounds.size.width;
+    if (logicalToPixelRatio > 0.0) {
+        return logicalToPixelRatio;
+    }
+
+    return [screen respondsToSelector:@selector(nativeScale)] ? screen.nativeScale : screen.scale;
+
+#elif TARGET_OS_OSX
+
+    NSView *view = (NSView *)viewOrNil;
+    NSScreen *screen = view ? (view.window.screen ?: [NSScreen mainScreen]) : [NSScreen mainScreen];
+    return screen ? screen.backingScaleFactor : 1.0;
+
+#else
+
+    return 1.0;
+
+#endif
+}

platform/ios/src/MLNMapView+Metal.mm

@@ -1,3 +1,4 @@
+#import "MLNDisplayUtils.h"
 #import "MLNFoundation_Private.h"
 #import "MLNLoggingConfiguration_Private.h"
 #import "MLNMapView+Metal.h"
@@ -32,14 +33,6 @@
 
 @end
 
-namespace {
-CGFloat contentScaleFactor() {
-    return [UIScreen instancesRespondToSelector:@selector(nativeScale)]
-        ? [[UIScreen mainScreen] nativeScale]
-        : [[UIScreen mainScreen] scale];
-}
-} // namespace
-
 class MLNMapViewMetalRenderableResource final : public mbgl::mtl::RenderableResource {
 public:
     MLNMapViewMetalRenderableResource(MLNMapViewMetalImpl& backend_)
@@ -164,11 +157,12 @@ void MLNMapViewMetalImpl::createView() {
     }
 
     id<MTLDevice> device = (__bridge id<MTLDevice>)resource.getBackend().getDevice().get();
+    const auto scaleFactor = MLNEffectiveScaleFactorForView(resource.mtlView);
 
     resource.mtlView = [[MTKView alloc] initWithFrame:mapView.bounds device:device];
     resource.mtlView.delegate = resource.delegate;
     resource.mtlView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
-    resource.mtlView.contentScaleFactor = contentScaleFactor();
+    resource.mtlView.contentScaleFactor = scaleFactor;
     resource.mtlView.contentMode = UIViewContentModeCenter;
     resource.mtlView.colorPixelFormat = MTLPixelFormatBGRA8Unorm;
     resource.mtlView.depthStencilPixelFormat = MTLPixelFormatDepth32Float_Stencil8;
@@ -222,9 +216,10 @@ UIImage* MLNMapViewMetalImpl::snapshot() {
 }
 
 void MLNMapViewMetalImpl::layoutChanged() {
-    const auto scaleFactor = contentScaleFactor();
-    size = { static_cast<uint32_t>(mapView.bounds.size.width * scaleFactor),
-             static_cast<uint32_t>(mapView.bounds.size.height * scaleFactor) };
+    const auto scaleFactor = MLNEffectiveScaleFactorForView(mapView);
+    const auto screenSize = mapView.window.screen.nativeBounds.size;
+    size = { static_cast<uint32_t>(screenSize.width * scaleFactor),
+             static_cast<uint32_t>(screenSize.height * scaleFactor) };
 }
 
 MLNBackendResource* MLNMapViewMetalImpl::getObject() {