Mix Swift and C++

4:10 - Calling a C++ method from Swift

func loadImage(_ image: UIImage) {
    // Load an image into the shared C++ class.
    CxxImageEngine.shared.pointee.loadImage(image)
}

4:20 - Import a C++ framework

import CxxImageKit

4:45 - Import the Generated Header

#import "SampleApp-Swift.h"

4:57 - Calling a Swift method in C++

- (IBAction)openPhotoLibrary:(UIButton *)sender {
    // Construct SwiftUI view
    SampleApp::ImagePicker::init().present(self);
}

8:22 - Using the SWIFT_COMPUTED_PROPERTY attribute

int  getValue() const SWIFT_COMPUTED_PROPERTY;
void setValue(int newValue);

8:42 - Using the SWIFT_SHARED_REFERENCE attribute

struct SWIFT_SHARED_REFERENCE(retain, release) CxxReferenceType;

8:52 - Using the SWIFT_RETURNS_INDEPENDENT_VALUE attribute

SWIFT_RETURNS_INDEPENDENT_VALUE 
std::string_view networkName() const;

10:45 - Using a for-loop to iterate over a C++ std::vector in Swift

// Get every image out of the shared C++ class.
for image in CxxImageEngine.shared.pointee.getImages() {
    let uiImage = CxxImageEngine.shared.pointee.uiImageFrom(image)
    UIImageWriteToSavedPhotosAlbum(uiImage, nil, nil, nil)
}

13:54 - Import swift/bridging

#import <swift/bridging>

14:01 - Applying the SWIFT_SHARED_REFERENCE attribute to CxxImageEngine

struct SWIFT_SHARED_REFERENCE(IKRetain, IKRelease) CxxImageEngine {
    // ...
};

14:53 - Applying the SWIFT_COMPUTED_PROPERTY attribute to getImages

/// \returns all images that have been loaded into the engine. Includes any modifications that were
/// applied to the images.
SWIFT_COMPUTED_PROPERTY
inline std::vector<Image *_Nonnull> getImages() const;

15:06 - Updated for-loop using the "images" computed property

// Get every image out of the shared C++ class.
for image in CxxImageEngine.shared.pointee.images {
    let uiImage = CxxImageEngine.shared.pointee.uiImageFrom(image)
    UIImageWriteToSavedPhotosAlbum(uiImage, nil, nil, nil)
}