如何裁剪 UIImagePickerController 拍摄的照片，因为它正在显示

Question

当我使用 UIImagePickerController 拍照时，屏幕上显示的图片比显示的要多...我如何拍照/裁剪它，使其与我在屏幕上看到的完全一样？

编辑：我将添加代码，以指定我的问题：

- (void)showImagePickerForSourceType:(UIImagePickerControllerSourceType)sourceType
{

UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
imagePickerController.modalPresentationStyle = UIModalPresentationCurrentContext;
imagePickerController.sourceType = sourceType;
imagePickerController.delegate = self;
imagePickerController.showsCameraControls = NO;
imagePickerController.allowsEditing = YES;

if (sourceType == UIImagePickerControllerSourceTypeCamera)
{
    [[NSBundle mainBundle] loadNibNamed:@"OverlayView" owner:self options:nil];
    self.overlayView.frame = imagePickerController.cameraOverlayView.frame;
    imagePickerController.cameraOverlayView = self.overlayView;
    //self.overlayView = nil;
    self.overlayImage.image = self.imageView.image;
    self.overlayImage.alpha = 0.5;

    UISlider *slider=[[UISlider alloc]initWithFrame:CGRectMake(60, 80, 200, 30)];
    [slider setMaximumValue:1.0];
    [slider setMinimumValue:0.0];
    [slider setValue:0.5];
    [slider addTarget:self action:@selector(sliderChanged:)  forControlEvents:UIControlEventValueChanged];

    if (self.working == TRUE)
    {
        [imagePickerController.cameraOverlayView addSubview:self.overlayImage];
        [imagePickerController.cameraOverlayView addSubview:slider];
    }
}

self.imagePickerController = imagePickerController;
[self presentViewController:self.imagePickerController animated:YES completion:nil];
}

didFinishPickingMediaWithInfo:

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
[self dismissViewControllerAnimated:YES completion:NULL];

//this works, image is displayed
UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
//this doesn't work, image is nil
UIImage *image = [info objecyForKey:UIImagePickerControllerEditedImage];    

[self.imageView setImage:image];
self.working = TRUE;

self.imagePickerController = nil;
//[self dismissViewControllerAnimated:YES completion:NULL];
}

imagePickerController.showsCameraControls = NO; 时我可以使用 UIImagePickerControllerEditedImage 吗？

Answer 1

您可以根据信息字典的键获取原始图像或裁剪图像。

pickedImageEdited 将是您要查找的裁剪图像，pickedImageOriginal 将是完整的原始图像。

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    UIImage *pickedImageOriginal = [info objectForKey:UIImagePickerControllerOriginalImage];

    UIImage *pickedImageEdited = [info objectForKey:UIImagePickerControllerEditedImage];

    //do your stuff

    [self dismissViewControllerAnimated:YES completion:nil];
}

Answer 2

只是将其发布为答案，但我不确定发帖者是否要求提供编辑后的图像。

当您使用 UIImagePickerController 拍照时，选取器仅显示拍照时实际拍摄的部分图像，如下图所示，其中黑线是 iPhone 的屏幕。

您从相机获得的图像是全尺寸图像，但屏幕上只是图像的中心，图像的宽度或高度都达到了屏幕尺寸。

您需要做的就是从上图所示的图像中获取中心，然后您就可以在屏幕上看到与您的图像完全相同的图像。

Answer 3

在 Wim 的回答之后，我想出了这样的解决方案：

UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];

UIGraphicsBeginImageContext(CGSizeMake(720, 960));
[image drawInRect: CGRectMake(0, 0, 720, 960)];
UIImage *smallImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

CGRect cropRect = CGRectMake(40, 0, 640, 960);

CGImageRef imageRef = CGImageCreateWithImageInRect([smallImage CGImage], cropRect);
[self.imageView setImage:[UIImage imageWithCGImage:imageRef]];

如您所见，这是为 3.5 英寸 iPhone 屏幕制作的，似乎可以工作，但代码取决于设备，还是有更好的解决方案？