UIImage 不会裁剪

Question

用户使用相机拍照 (UIImagePickerController)。但是，我无法裁剪它 - 或者我尝试了一下，它会返回完全相同的照片。

在viewDidAppear我创建图像选择器控制器：

if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
{
    ipc = [[UIImagePickerController alloc] init];
    ipc.delegate = self;

    ipc.sourceType = UIImagePickerControllerSourceTypeCamera;
    ipc.showsCameraControls = NO;

    [[NSBundle mainBundle] loadNibNamed:@"SnapItCameraView" owner:self options:nil];
    self.overlayView.frame = ipc.cameraOverlayView.frame;
    ipc.cameraOverlayView = self.overlayView;
    self.overlayView = nil;
    CGAffineTransform translate = CGAffineTransformMakeTranslation(0.0, 71.0); 
    ipc.cameraViewTransform = translate;
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    CGFloat screenHeight = screenRect.size.height;
    CGFloat scaleCamera = screenHeight / 426;

    CGAffineTransform scale = CGAffineTransformScale(translate, scaleCamera, scaleCamera);
    ipc.cameraViewTransform = scale;
    ipc.showsCameraControls = NO;
    ipc.tabBarController.tabBar.hidden = YES;
    ipc.allowsEditing = YES;
    [ipc setAllowsEditing:YES];

    [self presentViewController:ipc animated:YES completion:nil];
}

在didFinishPickingMediaWithInfo

UIImage* theImage = [info objectForKey:UIImagePickerControllerOriginalImage];
UIImageWriteToSavedPhotosAlbum(theImage, nil, nil, nil);             
[self ordinaryCrop:theImage toRect:CGRectMake(20, 0, 250, 250)];
UIImageWriteToSavedPhotosAlbum(theImage, nil, nil, nil);

裁剪：

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

但图像在裁剪后完全一样。我尝试了解决方案in this post，但是 UIImage* theImage = [info objectForKey:UIImagePickerControllerEditedImage]; 返回零

It's different from [this post][2] because, as the bounty answer points out, 

“如果选择图像，AllowsEditing 属性仅允许用户裁剪为正方形。”用户没有选择图像，我也没有尝试专门裁剪为正方形。我正在尝试裁剪它。

Answer 1

您从您的ordinaryCrop 函数返回cropped，但您在didFinishPickingMediaWithInfo 中没有对其进行任何操作，您只需再次保存原始图像。

你想要的是：

UIImage* theImage = [info objectForKey:UIImagePickerControllerOriginalImage];
UIImageWriteToSavedPhotosAlbum(theImage, nil, nil, nil);             
UIImage *croppedImage = [self ordinaryCrop:theImage toRect:CGRectMake(20, 0, 250, 250)];
UIImageWriteToSavedPhotosAlbum(croppedImage, nil, nil, nil);

Answer 2

拿一个 UIButton 试试这个：

1.

 UIButton *addImage_Button;

2.

-(IBAction)addImage_Button:(id)sender
{
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.delegate = self;
    picker.allowsEditing = YES; //THIS IS FOR CROPPING
    picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    [self presentViewController:picker animated:YES completion:NULL];
}

3.

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    UIImage *chosenUserImage = info[UIImagePickerControllerEditedImage];
    chosenUserImage = [chosenUserImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    addImage_Button.imageView.contentMode = UIViewContentModeScaleAspectFill;
    [addImage_Button setImage:chosenUserImage forState:UIControlStateNormal];
    [picker dismissViewControllerAnimated:YES completion:NULL];

}

4.

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    [picker dismissViewControllerAnimated:YES completion:NULL];
}