iPhone - 镜像从前置摄像头拍摄的照片

Question

使用iPhone 4的前置摄像头拍摄照片时,拍摄的照片与iPhone屏幕上显示的照片相比较.我怎样才能恢复UIImage(不是UIImageView)的"屏幕"视图,并能够像这样保存它？

我试过了 :

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.它与屏幕上显示的几乎相同,但保存的图像失真.

那么......我怎样才能恢复UIImage(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();

但这只是一个黑色的图像.

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回答了,但上面的答案对我不起作用,以防有其他人......

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();
    }

和newImage是你的新图像,具有向上的方向

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);

这是内存写的,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，但最初获得的图像是正确的。拍摄带有文字的图片进行比较。

Answer 5

安德鲁公园的答案很有效.这是Swift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
}