ios 圖片方向糾正

- (UIImage *)fixOrientation:(UIImage *)srcImg {    if (srcImg.imageOrientation == UIImageOrientationUp) return srcImg;    CGAffineTransform transform = CGAffineTransformIdentity;    switch (srcImg.imageOrientation) {        case UIImageOrientationDown:        case UIImageOrientationDownMirrored:            transform = CGAffineTransformTranslate(transform, srcImg.size.width, srcImg.size.height);            transform = CGAffineTransformRotate(transform, M_PI);            break;                    case UIImageOrientationLeft:        case UIImageOrientationLeftMirrored:            transform = CGAffineTransformTranslate(transform, srcImg.size.width, 0);            transform = CGAffineTransformRotate(transform, M_PI_2);            break;                    case UIImageOrientationRight:        case UIImageOrientationRightMirrored:            transform = CGAffineTransformTranslate(transform, 0, srcImg.size.height);            transform = CGAffineTransformRotate(transform, -M_PI_2);            break;        case UIImageOrientationUp:        case UIImageOrientationUpMirrored:            break;    }        switch (srcImg.imageOrientation) {        case UIImageOrientationUpMirrored:        case UIImageOrientationDownMirrored:            transform = CGAffineTransformTranslate(transform, srcImg.size.width, 0);            transform = CGAffineTransformScale(transform, -1, 1);            break;                    case UIImageOrientationLeftMirrored:        case UIImageOrientationRightMirrored:            transform = CGAffineTransformTranslate(transform, srcImg.size.height, 0);            transform = CGAffineTransformScale(transform, -1, 1);            break;        case UIImageOrientationUp:        case UIImageOrientationDown:        case UIImageOrientationLeft:        case UIImageOrientationRight:            break;    }        CGContextRef ctx = CGBitmapContextCreate(NULL, srcImg.size.width, srcImg.size.height,                                             CGImageGetBitsPerComponent(srcImg.CGImage), 0,                                             CGImageGetColorSpace(srcImg.CGImage),                                             CGImageGetBitmapInfo(srcImg.CGImage));    CGContextConcatCTM(ctx, transform);    switch (srcImg.imageOrientation) {        case UIImageOrientationLeft:        case UIImageOrientationLeftMirrored:        case UIImageOrientationRight:        case UIImageOrientationRightMirrored:            CGContextDrawImage(ctx, CGRectMake(0,0,srcImg.size.height,srcImg.size.width), srcImg.CGImage);            break;                    default:            CGContextDrawImage(ctx, CGRectMake(0,0,srcImg.size.width,srcImg.size.height), srcImg.CGImage);            break;    }        CGImageRef cgimg = CGBitmapContextCreateImage(ctx);    UIImage *img = [UIImage imageWithCGImage:cgimg];    CGContextRelease(ctx);    CGImageRelease(cgimg);    return img;}