在Swift iOS中使用OpenCV

OpenCV是一个用C ++编写的框架。 Apple的参考告诉我们

OpenCV is a framework written in C++. Apple's reference tell us that

您无法直接将C ++代码导入Swift。相反，为C ++代码创建一个Objective-C或C包装器。

You cannot import C++ code directly into Swift. Instead, create an Objective-C or C wrapper for C++ code.

所以你不能在swift项目中直接导入和使用OpenCV，但这实际上并不坏，因为你（需要）继续使用框架的C ++语法，这在整个网络上都有很好的文档。

so you cannot directly import and use OpenCV in a swift project, but this is actually not bad at all because you (need) continue to use the C++ syntax of the framework which is pretty well documented all over the net.

那么怎么做你继续吗？

1. 创建一个新的Objective-C ++类（.h， .mm ）来调用C ++ OpenCV

1. Create a new Objective-C++ class (.h, .mm) for calling C++ OpenCV

OpenCVWrapper.h

#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>

@interface OpenCVWrapper : NSObject

    + (UIImage *)processImageWithOpenCV:(UIImage*)inputImage;

@end

OpenCVWrapper.mm （使用文件 - >新建... Objective-C向导并将.m文件重命名为.mm）

OpenCVWrapper.mm (use the File -> New... Wizard for Objective-C and rename the .m file to .mm)

#include "OpenCVWrapper.h"
#import "UIImage+OpenCV.h" // See below to create this

#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

@implementation OpenCVWrapper : NSObject

    + (UIImage *)processImageWithOpenCV:(UIImage*)inputImage {
        Mat mat = [inputImage CVMat];

        // do your processing here
        ...

        return [UIImage imageWithCVMat:mat];
    }

@end

作为创建新的替代方案诸如OpenCVWrapper.h / mm示例之类的类可以使用Objective-C类别来扩展具有OpenCV功能的现有Objective-C类。例如UIImage + OpenCV类别：

As an alternative to creating new classes such as the example OpenCVWrapper.h/mm you can use Objective-C categories to extend existing Objective-C classes with OpenCV functionality. For instance UIImage+OpenCV category:

UIImage + OpenCV.h

#import <UIKit/UIKit.h>
#import <opencv2/opencv.hpp>

@interface UIImage (OpenCV)

    //cv::Mat to UIImage
+ (UIImage *)imageWithCVMat:(const cv::Mat&)cvMat;
- (id)initWithCVMat:(const cv::Mat&)cvMat;

    //UIImage to cv::Mat
- (cv::Mat)CVMat;
- (cv::Mat)CVMat3;  // no alpha channel
- (cv::Mat)CVGrayscaleMat;

@end

UIImage + OpenCV.mm

参见 https://github.com/foundry/OpenCVSwiftStitch/blob/master/SwiftStitch/UIImage%2BOpenCV.mm

1. 更新 Bridging-Header 通过导入我们新创建的包装器（ #importOpenCVWrapper.h）来使您创建的所有Objective-C ++类可供Swift使用

1. Update the Bridging-Header to make all Objective-C++ classes you created available to Swift by importing our newly created wrappers (#import "OpenCVWrapper.h")

在Swift文件中使用你的包装器：

Use your wrapper in your Swift files:

让image = UIImage（命名为：image.jpeg ）
let processedImage = OpenCVWrapper.processImageWithOpenCV（image）

let image = UIImage(named: "image.jpeg") let processedImage = OpenCVWrapper.processImageWithOpenCV(image)

桥中包含的所有Objective-C ++类标题可直接从Swift获得。

All Objective-C++ classes included in the bridge header are available directly from Swift.