In my iOS application I'm writing, I deal with PNGs because I deal with the alpha channel. For some reason, I can load a PNG into my imageView just fine, but when it comes time to either copy the image out of my application (onto the PasteBoard) or save the image to my camera roll, the image rotates 90 degrees.
I've searched everywhere on this, and one of the things I learned is that if I used JPEGs, I wouldn't have this problem (it sounds), due to the EXIF information.
My app has full copy/paste functionality, and here's the kicker (I'll write this in steps so it is easier to follow):
I am 100% sure my copy and paste code isn't what is wrong here, because if I go back to Step 2 above, and click "save", the photo saves to my library but it is rotated 90 degrees!
What is even more strange is that it seems to work fine with images downloaded from the internet, but is very hit or miss with images I manually took with the phone. Some it works, some it doesn't...
Does anybody have any thoughts on this? Any possible work arounds I can use? I'm pretty confident in the code being it works for about 75% of my images. I can post the code upon request though.
Took a few days, but I finally figured it out thanks to the answer @Dondragmer posted. But I figured I'd post my full solution.
So basically I had to write a method to intelligently auto-rotate my images. The downside is that I have to call this method everywhere throughout my code and it is kind of processor intensive, especially when working on mobile devices, but the plus side is that I can take images, copy images, paste images, and save images and they all rotate properly. Here's the code I ended up using (the method isn't 100% complete yet, still need to edit memory leaks and what not).
I ended up learning that the very first time an image was insert into my application (whether that be due to a user pressing "take image", "paste image", or "select image", for some reason it insert just fine without auto rotating. At this point, I stored whatever the rotation value was in a global variable called imageOrientationWhenAddedToScreen. This made my life easier because when it came time to manipulate the image and save the image out of the program, I simply checked this cached global variable and determined if I needed to properly rotate the image.
- (UIImage*) rotateImageAppropriately:(UIImage*) imageToRotate {
//This method will properly rotate our image, we need to make sure that
//We call this method everywhere pretty much...
CGImageRef imageRef = [imageToRotate CGImage];
UIImage* properlyRotatedImage;
if (imageOrientationWhenAddedToScreen == 0) {
//Don't rotate the image
properlyRotatedImage = imageToRotate;
} else if (imageOrientationWhenAddedToScreen == 3) {
//We need to rotate the image back to a 3
properlyRotatedImage = [UIImage imageWithCGImage:imageRef scale:1.0 orientation:3];
} else if (imageOrientationWhenAddedToScreen == 1) {
//We need to rotate the image back to a 1
properlyRotatedImage = [UIImage imageWithCGImage:imageRef scale:1.0 orientation:1];
}
return properlyRotatedImage;
}
I am still not 100% sure why Apple has this weird image rotation behavior (try this... Take your phone and turn it upside down and take a picture, you'll notice that the final picture turns out right side up - perhaps this is why Apple has this type of functionality?).
I know I spent a great deal of time figuring this out, so I hope it helps other people!