相册里的照片是有方向，再根据图片的方向，再反回来就好了！

相册里的照片是有方向，再根据图片的方向，再反回来就好了！

+ (void)fixOrientation:(UIImage *)aImage {

if (aImage==nil || !aImage) {

return;

}

// No-op if the orientation is already correct

if (aImage.imageOrientation == UIImageOrientationUp) return;

// 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;

UIImageOrientation orientation=aImage.imageOrientation;

int orientation_=orientation;

switch (orientation_) {

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;

}

switch (orientation_) {

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;

}

// Now we draw the underlying CGImage into a new context, applying the transform

// calculated above.

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

CGImageGetBitsPerComponent(aImage.CGImage), 0,

CGImageGetColorSpace(aImage.CGImage),

CGImageGetBitmapInfo(aImage.CGImage));

CGContextConcatCTM(ctx, transform);

switch (aImage.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;

}

// 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);

aImage=img;

img=nil;

}