UIImagePickerController bug

问题

I think I found a bug in latest iOS 7 by running an app with Base SDK set to iOS 6.1 (possibly even lower versions too, haven't tested that out yet)

I have this image in my photo library: http://i.imgur.com/7KUIGLt.jpg

I present a UIImagePickerController via:

UIImagePickerController *vc = [[UIImagePickerController alloc] init];
vc.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
vc.delegate = self;
vc.allowsEditing = YES;
[self presentViewController:vc animated:YES completion:nil];

I save the chosen image to my desktop (I am running this on simulator, but this works on device too)

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

    UIImage* outputImage = [info objectForKey:UIImagePickerControllerEditedImage];
    if (outputImage == nil) {
        outputImage = [info objectForKey:UIImagePickerControllerOriginalImage];
    }
    NSData *d = UIImagePNGRepresentation(outputImage);
    [d writeToFile:@"/Users/Admin/Desktop/test.png" atomically:YES];
    [self dismissViewControllerAnimated:YES completion:nil];
}

This is the resulting image:

Notice the big black bar to the right. What's causing this?

To reproduce this, you need:

iOS 7
App with Base SDK set to 6.1 (maybe even lower SDKs too, i haven't tried yet)
iPhone 5/5c/5s
Only happens to pictures that were taken with iPhone 5/5c/5s camera (you can use the original image I linked above for testing)

NOTE: Just to be clear, the black bar is part of the actual image. The image you see there is not a screenshot of a UIImageView, but the actual image saved to disk and uploaded here...

回答1:

Your question is "What's causing this?" So I'll focus on that instead of giving a workaround. This is definitely a bug in iOS 7 dealing with edited images in lower base SDKs. We can also rule out that XCode 5 & Base SDK 6.1 causing this because I'm getting the same issue with XCode 4.6.3 & 6.1 SDK running on iOS 7 Simulator.

The source of the problem is that the CropRect values that are calculated by the SDK are wrong. If you'll print out the info NSDictionary from imagePickerController:didFinishPickingMediaWithInfo you'll see that:

iOS 7 running any SDK lower than 7 we'll get:

UIImagePickerControllerCropRect = "NSRect: {{154, 495}, {1705, 1705}}";

While running iOS 6 or 5 with their SDK will give us:

UIImagePickerControllerCropRect = "NSRect: {{0, 149}, {1704, 1705}}";

You're probably saying, hmm, those y values are changing between SDKs too. Well, yea, if you'll slide your pic all the way down and select it you'll also get a black bar at the bottom of the picture.

Suggested Solutions:

File a bug report to Apple here ...Did that!
Don't use UIImagePickerControllerEditedImage and take the original picture instead.
Calculate and do the cropping your self.
Use a 3rd party cropping library such as PEPhotoCropEditor or SSPhotoCropperViewController

Edit - very simple solution added by fan of the answer!

Amazingly, it can be this simple and elegant to crop it yourself:

{
// There is a bug in iOS. When using ALBUM, you must crop it yourself:

fromAlbum = [info objectForKey:UIImagePickerControllerOriginalImage];
fromAlbum = [fromAlbum fixOrientation];

CGRect crop = [[info valueForKey:@"UIImagePickerControllerCropRect"] CGRectValue];
fromAlbum = [self ordinaryCrop:fromAlbum toRect:crop];
}

Here's the whole routine ordinaryCrop:toRect:

-(UIImage *)ordinaryCrop:(UIImage *)imageToCrop toRect:(CGRect)cropRect
 {
 CGImageRef imageRef = CGImageCreateWithImageInRect([imageToCrop CGImage], cropRect);
 UIImage *cropped = [UIImage imageWithCGImage:imageRef];
 CGImageRelease(imageRef);
 return cropped;
 }

Now as Jesse points out, it is critical to rotate the image properly. This absolutely incredible piece of code by Anomie does the job:

iOS UIImagePickerController result image orientation after upload

Fixing UIImage orientation .. UIImage+fixOrientation.h

It's that simple, hope it helps someone. Thanks again for the priceless answers here.

回答2:

I believe we ended up working around similar issues by never asking for the edited image directly; ask for the original image and the crop information (UIImagePickerControllerCropRect) and do the cropping yourself. Note that you need to worry about rotations in the source image if you do the cropping yourself.

You might find the answer in this question helpful for implementing this work-around.

回答3:

Try find and change mode (Aspect Fit, Aspect Fill, Scale to Fill) programmatically.

回答4:

I'm trying to reproduce this bug. And have no luck on simulator, simulator 64-bit and iPad mini. All running iOS 7.0.

I put your code in my app:

UIImage *image = [info valueForKey:UIImagePickerControllerEditedImage];
if (!image)
    image = [info valueForKey:UIImagePickerControllerOriginalImage];

// Save photo to custom album only if taken by camera
if (picker.sourceType == UIImagePickerControllerSourceTypeCamera)
    [ALAssetsLibrary saveImageToCustomAlbum:image
                                   assetURL:[info valueForKey:UIImagePickerControllerReferenceURL]];


NSData *d = UIImagePNGRepresentation(image);
[d writeToFile:@"/Volumes/Alko/Temp/test.png" atomically:YES];

UIImageWriteToSavedPhotosAlbum(image, nil, NULL, nil);

[self setImage:image];
[self dismissPicker:picker];
[self photoPickerDidFinish];

And it works correct using image downloaded from http://i.imgur.com/7KUIGLt.jpg. I think you have issue in your app, not in UIImagePickerController.

来源：https://stackoverflow.com/questions/19397873/uiimagepickercontroller-bug

标签

ios

objective-c

cocoa-touch

ios7

uiimagepickercontroller