11

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

我试过 ：

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

然后把它放在屏幕上。它与屏幕上看到的几乎相同，但保存的图像失真。

所以......我怎样才能恢复 UIImage 的“屏幕上”视图（不是 UIImageView），并能够像这样保存它？

我也试过这种方式：

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的图像。

4

8 回答 8

27 
- (void)didTakePicture:(UIImage *)picture
{
    UIImage * flippedImage = [UIImage imageWithCGImage:picture.CGImage scale:picture.scale orientation:UIImageOrientationLeftMirrored];
    picture = flippedImage;
}
于 2011-05-10T06:28:50.307 回答
10

我知道这个问题已经回答了，但是上面的答案对我不起作用，所以万一还有其他人......

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();
    }

并且 newImage 是您向上方向的新图像

于 2012-02-26T04:10:20.240 回答
6

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);

这是内存不足，没有编译器的帮助，请不要复制和粘贴...

于 2011-03-31T20:31:21.410 回答
5

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。拍一张有文字的照片进行比较。

于 2013-01-15T15:44:20.963 回答
5

Andrew Park 的回答效果很好。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
}
于 2016-01-17T19:22:11.133 回答
5

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
}
于 2016-09-20T17:38:14.747 回答
3

作为其他答案，我遇到了同样的问题。但是仅仅翻转最终的图像只是答案的一半，因为当你用前置摄像头拍照时，UIPickerController 显示的预览图像仍然是倒置的（镜像）。

基于来自互联网的一些代码，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，您只需将这两行代码与您的代码一起调用UIImagePickerController：

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。

于 2013-07-21T19:17:23.733 回答
0

我想投票支持@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];
}
于 2015-07-08T06:12:38.743 回答