iPhone - 镜像回从前置摄像头拍摄的照片

Question

使用 iPhone 4 的前置摄像头拍照时，拍摄的照片与 iPhone 屏幕上看到的图像是镜像的。我如何恢复 UIImage （而不是 UIImageView）的“屏幕上”视图，并能够像这样保存它？

我尝试过：

UIImage* transformedImage = [UIImage imageWithCGImage:pickedImage.CGImage scale:1.0 orientation:UIImageOrientationLeftMirrored];
UIImageWriteToSavedPhotosAlbum (transformedImage, self, @selector(photoSaved:didFinishSavingWithError:contextInfo:), nil);

然后将其放在屏幕上。它与屏幕上看到的几乎相同，但保存的图像失真。

那么...我如何恢复 UIImage （而不是 UIImageView）的“屏幕”视图，并能够像这样保存它？

我也尝试过这种方式：

UIImage* pickedImage = [[info objectForKey:UIImagePickerControllerOriginalImage] retain];
UIImage* transformedImage;

CGSize imageSize = pickedImage.size;
UIGraphicsBeginImageContextWithOptions(imageSize, YES, 1.0);
GContextRef ctx = UIGraphicsGetCurrentContext();

CGContextRotateCTM(ctx, 3.14);  // rotate by 180°
CGContextScaleCTM(ctx, 1.0, -1.0); // flip vertical
CGContextDrawImage(ctx, CGRectMake(0.0, 0.0, imageSize.width, imageSize.height), pickedImage.CGImage);
transformedImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

但这只是给出了一个黑色图像。

Answer 1

- (void)didTakePicture:(UIImage *)picture
{
    UIImage * flippedImage = [UIImage imageWithCGImage:picture.CGImage scale:picture.scale orientation:UIImageOrientationLeftMirrored];
    picture = flippedImage;
}

Answer 2

我知道这个问题已经得到解答，但上面的答案对我不起作用，所以万一还有其他问题......

UIImage *theImage = [info objectForKey:UIImagePickerControllerOriginalImage];
    if (picker.cameraDevice == UIImagePickerControllerCameraDeviceFront) {
        CGSize imageSize = theImage.size;
        UIGraphicsBeginImageContextWithOptions(imageSize, YES, 1.0);
        CGContextRef ctx = UIGraphicsGetCurrentContext();
        CGContextRotateCTM(ctx, M_PI/2);
        CGContextTranslateCTM(ctx, 0, -imageSize.width);
        CGContextScaleCTM(ctx, imageSize.height/imageSize.width, imageSize.width/imageSize.height);
        CGContextDrawImage(ctx, CGRectMake(0.0, 0.0, imageSize.width, imageSize.height), theImage.CGImage);
        UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
    }

newImage 是您的新图像，方向向上

Answer 3

最好的方法是将图像绘制到新的上下文中。

CGSize imageSize = pickedImage.size;
UIGraphicsBeginImageContextWithOptions(imageSize, YES, 1.0);
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(ctx, imageSize.width, 0.0);
CGContextScaleCTM(ctx, -1.0, 1.0);
CGContextDrawImage(ctx, pickedImage.CGImage, CGRectMake(0.0, 0.0, imageSize.width, imageSize.height));
UIImage *transformedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum (transformedImage, self, @selector(photoSaved:didFinishSavingWithError:contextInfo:), nil);

这是在内存不足的情况下编写的，没有编译器的帮助，请不要复制和粘贴......

Answer 4

您可能想要镜像从相机获得的图像，但您最初获得的图像是正确的。拍一张带有文字的图片进行比较。

Answer 5

安德鲁·帕克的回答非常有效。这是斯威夫特版本。

func flipImage(image: UIImage!) -> UIImage! {
    let imageSize:CGSize = image.size;
    UIGraphicsBeginImageContextWithOptions(imageSize, true, 1.0);
    let ctx:CGContextRef = UIGraphicsGetCurrentContext()!;
    CGContextRotateCTM(ctx, CGFloat(M_PI/2.0));
    CGContextTranslateCTM(ctx, 0, -imageSize.width);
    CGContextScaleCTM(ctx, imageSize.height/imageSize.width, imageSize.width/imageSize.height);
    CGContextDrawImage(ctx, CGRectMake(0.0, 0.0, imageSize.width, imageSize.height), image.CGImage);
    let newImage:UIImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage
}

Answer 6

为 Swift 3 更新了一个稍微简单的答案：

func flipImage(image: UIImage) -> UIImage {
    guard let cgImage = image.cgImage else {
        // Could not form CGImage from UIImage for some reason.
        // Return unflipped image
        return image
    }
    let flippedImage = UIImage(cgImage: cgImage, 
                               scale: image.scale, 
                               orientation: .leftMirrored)
    return flippedImage
}

Answer 7

正如其他答案，我也遇到了同样的问题。但仅仅翻转最终图像只是答案的一半，因为当您使用前置摄像头拍照时 UIPickerController 显示的预览图像仍然是反转的（镜像）。

根据互联网上的一些代码，我创建了一个 Pod 来获得这种想要的行为：

https://github.com/lucasecf/ LEMirroredImagePicker

安装后，你只需要将这两行代码与你的 UIImagePickerController 一起调用即可：

self.mirrorFrontPicker = [[LEMirroredImagePicker alloc] initWithImagePicker:pickerController];
[self.mirrorFrontPicker mirrorFrontCamera];

就是这样，就这么简单。您可以在 github 链接的 README 中查看更多信息。

Answer 8

我想投票@Lucas Eduardo，我尝试将组件 LEImagePickerController 集成到我的项目中，如下所示：

- (void)onCamera:(id)sender {
    UIImagePickerController* imagePicker = [[UIImagePickerController alloc] init];
    imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
    imagePicker.cameraDevice = UIImagePickerControllerCameraDeviceFront;
    imagePicker.delegate = self;

    //cover the switch button at the top right corner, I just need user take photo with the front facing camera
    UIView* view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 40, 40)];
    view.center = CGPointMake(CGRectGetWidth(imagePicker.view.bounds) - CGRectGetWidth(view.bounds)/2, CGRectGetHeight(view.bounds)/2);
    view.backgroundColor = [UIColor blackColor];
    [imagePicker.view addSubview:view];

    LEMirroredImagePicker* mirrorFrontPicker = [[LEMirroredImagePicker alloc] initWithImagePicker:imagePicker];
    [mirrorFrontPicker mirrorFrontCamera];

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