问题
I have researched enough to get this working but not able to fix it. After taking picture from camera as long as I have image stored as UIImage, it's fine but as soon as I stored this image as PNG representation, its get rotated 90 degree.
Following is my code and all things I tried:
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
NSString *mediaType = [info valueForKey:UIImagePickerControllerMediaType];
if([mediaType isEqualToString:(NSString*)kUTTypeImage])
{
AppDelegate *delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
delegate.originalPhoto = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
NSLog(@"Saving photo");
[self saveImage];
NSLog(@"Fixing orientation");
delegate.fixOrientationPhoto = [self fixOrientation:[UIImage imageWithContentsOfFile:[delegate filePath:imageName]]];
NSLog(@"Scaling photo");
delegate.scaledAndRotatedPhoto = [self scaleAndRotateImage:[UIImage imageWithContentsOfFile:[delegate filePath:imageName]]];
}
[picker dismissModalViewControllerAnimated:YES];
[picker release];
}
- (void)saveImage
{
AppDelegate *delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
NSData *imageData = UIImagePNGRepresentation(delegate.originalPhoto);
[imageData writeToFile:[delegate filePath:imageName] atomically:YES];
}
Here fixOrientation and scaleAndRotateImage functions taken from here and here respectively. They works fine and rotate image when I apply them on UIImage but doesn't work if I save image as PNG representation and apply them.
Please refere the following picture after executing above functions:
回答1:
Starting with iOS 4.0 when the camera takes a photo it does not rotate it before saving, it
simply sets a rotation flag in the EXIF data of the JPEG.If you save a UIImage as a JPEG, it
will set the rotation flag.PNGs do not support a rotation flag, so if you save a UIImage as a
PNG, it will be rotated incorrectly and not have a flag set to fix it. So if you want PNG
images you must rotate them yourself, for that check this link.
回答2:
Swift 3.1 version of the UIImage extension posted by Rao:
extension UIImage {
func fixOrientation() -> UIImage {
if self.imageOrientation == UIImageOrientation.up {
return self
}
UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)
self.draw(in: CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height))
if let normalizedImage: UIImage = UIGraphicsGetImageFromCurrentImageContext() {
UIGraphicsEndImageContext()
return normalizedImage
} else {
return self
}
}
}
Usage:
let cameraImage = //image captured from camera
let orientationFixedImage = cameraImage.fixOrientation()
Swift 4/5:
UIImageOrientation.up has been renamed to UIImage.Orientation.up
回答3:
Swift 4.2
Add the following as UIImage extension,
extension UIImage {
func fixOrientation() -> UIImage? {
if self.imageOrientation == UIImage.Orientation.up {
return self
}
UIGraphicsBeginImageContext(self.size)
self.draw(in: CGRect(origin: .zero, size: self.size))
let normalizedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return normalizedImage
}
}
Example usage:
let cameraImage = //image captured from camera
let orientationFixedImage = cameraImage.fixOrientation()
回答4:
I have found the following tips to be hugely useful:
1. natural output is landscape
2. .width / .height ARE affected by .imageOrientation
3 use short dimension rather than .width
(1) the 'natural' output of the camera for stills IS LANDSCAPE.
this is counterintuitive. portrait is the only way offered by UIImagePickerController etc. But you will get UIImageOrientationRight as the "normal" orientation when using the "normal" portrait camera
(The way I remember this - the natural output for video is (of course) landscape; so stills are the same - even though the iPhone is all about portrait.)
(2) .width and .height are indeed affected by the .imageOrientation!!!!!!!!!
Be sure to do this, and try it both ways on your iPhone,
NSLog(@"fromImage.imageOrientation is %d", fromImage.imageOrientation);
NSLog(@"fromImage.size.width %f fromImage.size.height %f",
fromImage.size.width, fromImage.size.height);
you'll see that the .height and .width swap, "even though" the real pixels are landscape.
(3) simply using the "short dimension" rather than .width, can often solve many problems
I found this to be incredibly helpful. Say you want maybe the top square of the image:
CGRect topRectOfOriginal = CGRectMake(0,0, im.size.width,im.size.width);
that actually won't work, you'll get a squished image, when the camera is ("really") being held landscape.
however if you very simply do this
float shortDimension = fminf(im.size.width, im.size.height);
CGRect topRectOfOriginal = CGRectMake(0,0, shortDimension,shortDimension);
then "everything is fixed" and you actually "do not need to worry about" the orientation flag. Again point (3) is not a cure-all, but it very often does solve all problems.
Hope it helps someone save some time.
回答5:
Try this, You can use
NSData *somenewImageData = UIImageJPEGRepresentation(newimg,1.0);
instead of
NSData *somenewImageData = UIImagePNGRepresentation(newimg);
回答6:
I found this code here, which actually fixed it for me. For my app, I took a picture and saved it, and everytime I loaded it, it would have the annoying rotation attached (I looked up, and it's apparently something to do with the EXIF and the way iPhone takes and stores images). This code fixed it for me. I have to say, it was originally as an addition to a class / an extension /category (you can find the original from the link. I used it like below as a simple method, as I didn't really want to make a whole class or category for just this. I only used portrait, but I think the code works for any orientation. I'm not sure though
Rant over, here's the code:
- (UIImage *)fixOrientationForImage:(UIImage*)neededImage {
// No-op if the orientation is already correct
if (neededImage.imageOrientation == UIImageOrientationUp) return neededImage;
// 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 (neededImage.imageOrientation) {
case UIImageOrientationDown:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, neededImage.size.width, neededImage.size.height);
transform = CGAffineTransformRotate(transform, M_PI);
break;
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
transform = CGAffineTransformTranslate(transform, neededImage.size.width, 0);
transform = CGAffineTransformRotate(transform, M_PI_2);
break;
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, 0, neededImage.size.height);
transform = CGAffineTransformRotate(transform, -M_PI_2);
break;
case UIImageOrientationUp:
case UIImageOrientationUpMirrored:
break;
}
switch (neededImage.imageOrientation) {
case UIImageOrientationUpMirrored:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, neededImage.size.width, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
case UIImageOrientationLeftMirrored:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, neededImage.size.height, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
case UIImageOrientationUp:
case UIImageOrientationDown:
case UIImageOrientationLeft:
case UIImageOrientationRight:
break;
}
// Now we draw the underlying CGImage into a new context, applying the transform
// calculated above.
CGContextRef ctx = CGBitmapContextCreate(NULL, neededImage.size.width, neededImage.size.height,
CGImageGetBitsPerComponent(neededImage.CGImage), 0,
CGImageGetColorSpace(neededImage.CGImage),
CGImageGetBitmapInfo(neededImage.CGImage));
CGContextConcatCTM(ctx, transform);
switch (neededImage.imageOrientation) {
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
// Grr...
CGContextDrawImage(ctx, CGRectMake(0,0,neededImage.size.height,neededImage.size.width), neededImage.CGImage);
break;
default:
CGContextDrawImage(ctx, CGRectMake(0,0,neededImage.size.width,neededImage.size.height), neededImage.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;
}
I'm not sure how useful this will be for you, but I hope it helped :)
回答7:
Pls Try the following code
UIImage *sourceImage = ... // Our image
CGRect selectionRect = CGRectMake(100.0, 100.0, 300.0, 400.0);
CGImageRef resultImageRef = CGImageCreateWithImageInRect(sourceImage.CGImage,
selectionRect);
UIImage *resultImage = [[UIImage alloc] initWithCGImage:resultImageRef];
And
CGRect TransformCGRectForUIImageOrientation(CGRect source, UIImageOrientation orientation, CGSize imageSize) {
switch (orientation) {
case UIImageOrientationLeft: { // EXIF #8
CGAffineTransform txTranslate = CGAffineTransformMakeTranslation(imageSize.height, 0.0);
CGAffineTransform txCompound = CGAffineTransformRotate(txTranslate,M_PI_2);
return CGRectApplyAffineTransform(source, txCompound);
}
case UIImageOrientationDown: { // EXIF #3
CGAffineTransform txTranslate = CGAffineTransformMakeTranslation(imageSize.width, imageSize.height);
CGAffineTransform txCompound = CGAffineTransformRotate(txTranslate,M_PI);
return CGRectApplyAffineTransform(source, txCompound);
}
case UIImageOrientationRight: { // EXIF #6
CGAffineTransform txTranslate = CGAffineTransformMakeTranslation(0.0, imageSize.width);
CGAffineTransform txCompound = CGAffineTransformRotate(txTranslate,M_PI + M_PI_2);
return CGRectApplyAffineTransform(source, txCompound);
}
case UIImageOrientationUp: // EXIF #1 - do nothing
default: // EXIF 2,4,5,7 - ignore
return source;
}
}
...
UIImage *sourceImage = ... // Our image
CGRect selectionRect = CGRectMake(100.0, 100.0, 300.0, 400.0);
CGRect transformedRect = TransformCGRectForUIImageOrientation(selectionRect, sourceImage.imageOrientation, sourceImage.size);
CGImageRef resultImageRef = CGImageCreateWithImageInRect(sourceImage.CGImage, transformedRect);
UIImage *resultImage = [[UIImage alloc] initWithCGImage:resultImageRef];
I have referanced from following link have look for more detail
Best Regards :-)
回答8:
Try this code:
NSData *imageData = UIImageJPEGRepresentation(delegate.originalPhoto,100);
来源：https://stackoverflow.com/questions/10850184/ios-image-get-rotated-90-degree-after-saved-as-png-representation-data