强制 UIImagePickerController 裁剪方形图像

我们如何强制 UIImagePickerController 裁剪方形图像？

我到处寻找，但没有找到可靠的解决方案。谢谢

var imagePickerController: UIImagePickerController = UIImagePickerController();
imagePickerController.allowsEditing = true;
imagePickerController.delegate = self;
imagePickerController.sourceType = sourceType;



func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage!, editingInfo: [NSObject : AnyObject]!) {
    profilePictureSelected = true;

    profilePictureImageView.image = image;

    picker.dismissViewControllerAnimated(true, completion: nil);
}

在收到委托回调之前，您的操作都是正确的，在回调中您需要指定它是您要使用的编辑后的图像。请注意，我在这里使用了不同的委托方法。

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject : AnyObject]) {
    if let chosenImage = info[UIImagePickerControllerEditedImage] as? UIImage {

        profilePictureSelected = true;

        profilePictureImageView.image = chosenImage;
    }
    picker.dismissViewControllerAnimated(true, completion: nil);
}