[iOS開発]--撮影後の写真の回転が90度の問題を解決(Swiftバージョン付)

カメラを使用して写真を撮ると、以下のコードで示すように、UIImagePickerControllerのdelegateメソッドを呼び出します.

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
}

UIImagePickerControllerOriginalImageというkeyはinfo辞書から撮影後のUIImgeを取得できますが、ブレークポイントで画像を見ると90度回転していることがわかります.
ただし、このUIImageを使用してUIImage Viewのインスタンスに値を割り当てるなど、画像を直接使用すると、表示される画像はまったく問題ありません.
しかし、このUIImageを他の用途として使用すると、例えばサーバにアップロードすると問題が発生し、サーバにアップロードされた画像も90度回転します.
理由:UIImagePickerControllerOriginalImageというkeyはinfo辞書から撮影後のUIImageを取得でき、そのimageOrientation属性のデフォルトはUIImageOrientation Right、つまりデフォルトは左側に90度回転している.
方法1:
UIImagePickerControllerインスタンスを作成する場合、インスタンスの属性allowsEditingをYESに設定します.この値を設定すると、写真を撮った後に写真に枠が表示され、写真のトリミング編集ができます.UIImageOrientationUpではなく、UIImagePickerControllerControllerControllerEditedImageを使用して、UIImagePickerControllerEditedImageを使用して、UIImageOrientationはデフォルトのUIImageOrientationUpです.
方法2:
Categoryを使用して、UIImageの回転に関する問題を修正します.コードは次のとおりです.
OCバージョン:
UIImage+fixOrientation.h

#import 

@interface UIImage (fixOrientation)

- (UIImage *)fixOrientation;

@end

UIImage+fixOrientation.m

#import "UIImage+fixOrientation.h"

@implementation UIImage (fixOrientation)

- (UIImage *)fixOrientation {
    
    // No-op if the orientation is already correct
    if (self.imageOrientation == UIImageOrientationUp) return self;
    
    // We need to calculate the proper transformation to make the image upright.
    // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
    CGAffineTransform transform = CGAffineTransformIdentity;
    
    switch (self.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
            
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;
            
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
    }
    
    switch (self.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
            
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
    }
    
    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    CGContextRef ctx = CGBitmapContextCreate(NULL, self.size.width, self.size.height,
                                             CGImageGetBitsPerComponent(self.CGImage), 0,
                                             CGImageGetColorSpace(self.CGImage),
                                             CGImageGetBitmapInfo(self.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (self.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.height,self.size.width), self.CGImage);
            break;
            
        default:
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.width,self.size.height), self.CGImage);
            break;
    }
    
    // And now we just create a new UIImage from the drawing context
    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);
    return img;
}

@end

Swiftバージョン:

import UIKit

extension UIImage {
    //       
    func fixOrientation() -> UIImage {
        if self.imageOrientation == .up {
            return self
        }
        
        var transform = CGAffineTransform.identity
        
        switch self.imageOrientation {
        case .down, .downMirrored:
            transform = transform.translatedBy(x: self.size.width, y: self.size.height)
            transform = transform.rotated(by: .pi)
            break
            
        case .left, .leftMirrored:
            transform = transform.translatedBy(x: self.size.width, y: 0)
            transform = transform.rotated(by: .pi / 2)
            break
            
        case .right, .rightMirrored:
            transform = transform.translatedBy(x: 0, y: self.size.height)
            transform = transform.rotated(by: -.pi / 2)
            break
            
        default:
            break
        }
        
        switch self.imageOrientation {
        case .upMirrored, .downMirrored:
            transform = transform.translatedBy(x: self.size.width, y: 0)
            transform = transform.scaledBy(x: -1, y: 1)
            break
            
        case .leftMirrored, .rightMirrored:
            transform = transform.translatedBy(x: self.size.height, y: 0);
            transform = transform.scaledBy(x: -1, y: 1)
            break
            
        default:
            break
        }
        
        let ctx = CGContext(data: nil, width: Int(self.size.width), height: Int(self.size.height), bitsPerComponent: self.cgImage!.bitsPerComponent, bytesPerRow: 0, space: self.cgImage!.colorSpace!, bitmapInfo: self.cgImage!.bitmapInfo.rawValue)
        ctx?.concatenate(transform)
        
        switch self.imageOrientation {
        case .left, .leftMirrored, .right, .rightMirrored:
            ctx?.draw(self.cgImage!, in: CGRect(x: CGFloat(0), y: CGFloat(0), width: CGFloat(size.height), height: CGFloat(size.width)))
            break
            
        default:
            ctx?.draw(self.cgImage!, in: CGRect(x: CGFloat(0), y: CGFloat(0), width: CGFloat(size.width), height: CGFloat(size.height)))
            break
        }
        
        let cgimg: CGImage = (ctx?.makeImage())!
        let img = UIImage(cgImage: cgimg)
        
        return img
    }
}