iOS開發--解決拍照後照片旋轉90度的問題（附Swift版本），iosswift

iOS開發--解決拍照後照片旋轉90度的問題（附Swift版本），iosswift

當我們使用相機拍照後，調用UIImagePickerController的delegate方法，如下代碼所示：

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

通過UIImagePickerControllerOriginalImage這個key從info字典中可以擷取到拍照後的UIImage，但如果斷點查看圖片，我們會發現圖片是旋轉了90度的。

不過如果直接使用圖片，比如使用這個UIImage賦值給一個UIImageView的執行個體，顯示出來的圖片是完全沒有問題的。

但如果使用這個UIImage作他用，比如上傳到伺服器，就會出現問題了，上傳到伺服器的圖片也是旋轉了90度的。

 

原因：通過UIImagePickerControllerOriginalImage這個key從info字典中可以擷取到拍照後的UIImage，其imageOrientation屬性預設是UIImageOrientationRight，也就是說預設就是向左側旋轉了90度的。

解決方案如下:

方法一：建立UIImagePickerController執行個體的時候，設定執行個體的一個屬性allowsEditing為YES，設了這個值，拍完照片後會在照片上出現一個框框，可以對照片的裁剪編輯。在UIImagePickerController的代理方法中取照片的時候也就別用UIImagePickerControllerOriginalImage這個key來取了，而要用UIImagePickerControllerEditedImage，此時取出來的照片，它的imageOrientation是UIImageOrientationUp而不是預設的UIImageOrientationRight了。

 

方法二：有一個專門針對UIImage旋轉這個問題的很好的Category，代碼如下：

OC版本：

UIImage+fixOrientation.h

#import <UIKit/UIKit.h>@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版本：

 

import UIKitextension UIImage {    // 修複圖片旋轉    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    }}