iOS开发—— UIImage数据的保存

　　1、保存图片和方向

　　[userDefault setObject:UIImagePNGRepresentation(image) forKey:udUserImage];

　　[userDefault setObject:[NSNumber numberWithInteger:image.imageOrientation] forKey:udUserImageOrientation];

　　2、获取图片和方向

　　NSData* imageData = [userDefault objectForKey:udUserImage];

　　UIImage *userImage = [UIImage imageWithData:imageData];

　　NSInteger imageOrientation = [[userDefault objectForKey:udUserImageOrientation] integerValue];

　　3、显示图片

　　imageView.image = [self fixOrientationWithImage:userImage AndImageOrientation:imageOrientation];

- (UIImage *)fixOrientationWithImage:(UIImage *)aImage AndImageOrientation:(NSInteger)imageOrientation {

    if (imageOrientation == UIImageOrientationUp)

        return aImage;

    

    CGAffineTransform transform = CGAffineTransformIdentity;

    

    switch (imageOrientation) {

        case UIImageOrientationDown:

        case UIImageOrientationDownMirrored:

            transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);

            transform = CGAffineTransformRotate(transform, M_PI);

            break;

            

        case UIImageOrientationLeft:

        case UIImageOrientationLeftMirrored:

            transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);

            transform = CGAffineTransformRotate(transform, M_PI_2);

            break;

            

        case UIImageOrientationRight:

        case UIImageOrientationRightMirrored:

            transform = CGAffineTransformTranslate(transform, 0, aImage.size.height);

            transform = CGAffineTransformRotate(transform, -M_PI_2);

            break;

        default:

            break;

    }

    

    switch (imageOrientation) {

        case UIImageOrientationUpMirrored:

        case UIImageOrientationDownMirrored:

            transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);

            transform = CGAffineTransformScale(transform, -1, 1);

            break;

            

        case UIImageOrientationLeftMirrored:

        case UIImageOrientationRightMirrored:

            transform = CGAffineTransformTranslate(transform, aImage.size.height, 0);

            transform = CGAffineTransformScale(transform, -1, 1);

            break;

        default:

            break;

    }

    

    CGContextRef ctx = CGBitmapContextCreate(NULL, aImage.size.width, aImage.size.height,

                                             CGImageGetBitsPerComponent(aImage.CGImage), 0,

                                             CGImageGetColorSpace(aImage.CGImage),

                                             CGImageGetBitmapInfo(aImage.CGImage));

    CGContextConcatCTM(ctx, transform);

    switch (imageOrientation) {

        case UIImageOrientationLeft:

        case UIImageOrientationLeftMirrored:

        case UIImageOrientationRight:

        case UIImageOrientationRightMirrored:

            // Grr...

            CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);

            break;

            

        default:

            CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);

            break;

    }

    

    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);

    UIImage *img = [UIImage imageWithCGImage:cgimg];

    CGContextRelease(ctx);

    CGImageRelease(cgimg);

    return img;

}