- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
}复制代码
通过UIImagePickerControllerOriginalImage这个key从info字典中可以获取到拍照后的UIImage，但如果断点查看图片，我们会发现图片是旋转了90度的。
不过如果直接使用图片，比如使用这个UIImage赋值给一个UIImageView的实例，显示出来的图片是完全没有问题的。
但如果使用这个UIImage作他用，比如上传到服务器，就会出现问题了，上传到服务器的图片也是旋转了90度的。
原因：通过UIImagePickerControllerOriginalImage这个key从info字典中可以获取到拍照后的UIImage，其imageOrientation属性默认是UIImageOrientationRight，也就是说默认就是向左侧旋转了90度的。
解决方法如下:
方法一：创建UIImagePickerController实例的时候，设置实例的一个属性allowsEditing为YES，设了这个值，拍完照片后会在照片上出现一个框框，可以对照片的裁剪编辑。在UIImagePickerController的代理方法中取照片的时候也就别用UIImagePickerControllerOriginalImage这个key来取了，而要用UIImagePickerControllerEditedImage，此时取出来的照片，它的imageOrientation是UIImageOrientationUp而不是默认的UIImageOrientationRight了。
方法二：有一个专门针对UIImage旋转这个问题的很好的Category，代码如下：
OC版本：
UIImage+fixOrientation.h
#import <UIKit/UIKit.h>
@interface UIImage (fixOrientation)
- (UIImage *)fixOrientation;
@end
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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
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Swift版本：
import UIKit
extension UIImage {
// 修复图片旋转
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
}
}
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