在风景视图中拍摄的iPhone屏幕

Question

I'm running the app in landscape mode. What care do I have to take so that the screen shot taken is also in landscape mode.

I'm using the following code in iphone app with tabbar at bottom and taking screen shot, but its always in portrait mode only. why?

UIWindow *screenWindow = [[UIApplication sharedApplication] keyWindow];

UIGraphicsBeginImageContext(screenWindow.frame.size);
[screenWindow.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *screenshot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Answer 1

My previous answer was incorrect. I have worked on this and I have an answer for a landscape right screen shot. This will save a landscape right screen shot correctly to the camera roll. I have not tried landscape left.

This is a variation on an answer provided in another stackoverflow question here . The problem with that answer is that the screen shot always has an imageOrientation (read only) of UIImageOrientationUp. Therefore it is up to us to know what the orientation was and change it appropriately.

I hope this helps. If this works on landscape left or you get a variation that works on landscape left please post it.

 - (IBAction)cameraButtonClick:(id)sender {

    UIWindow *screenWindow = [[UIApplication sharedApplication] keyWindow];

    UIGraphicsBeginImageContext(screenWindow.frame.size);
    [screenWindow.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *screenshot = UIGraphicsGetImageFromCurrentImageContext();


UIImageWriteToSavedPhotosAlbum([self scaleAndRotateImage:screenshot], nil, nil, nil);

    UIGraphicsEndImageContext();
}

// Code from: http://discussions.apple.com/thread.jspa?messageID=7949889
- (UIImage *)scaleAndRotateImage:(UIImage *)image {
    int kMaxResolution = 640; // Or whatever

    CGImageRef imgRef = image.CGImage;

    CGFloat width = CGImageGetWidth(imgRef);
    CGFloat height = CGImageGetHeight(imgRef);


    CGAffineTransform transform = CGAffineTransformIdentity;
    CGRect bounds = CGRectMake(0, 0, width, height);
    if (width > kMaxResolution || height > kMaxResolution) {
        CGFloat ratio = width/height;
        if (ratio > 1) {
            bounds.size.width = kMaxResolution;
            bounds.size.height = roundf(bounds.size.width / ratio);
        }
        else {
            bounds.size.height = kMaxResolution;
            bounds.size.width = roundf(bounds.size.height * ratio);
        }
    }

    CGFloat scaleRatio = bounds.size.width / width;
    CGSize imageSize = CGSizeMake(CGImageGetWidth(imgRef), CGImageGetHeight(imgRef));
    CGFloat boundHeight;

    boundHeight = bounds.size.height;
    bounds.size.height = bounds.size.width;
    bounds.size.width = boundHeight;
    transform = CGAffineTransformMakeTranslation(imageSize.height, imageSize.width/2.0);
    transform = CGAffineTransformRotate(transform, M_PI / 2.0);

    UIGraphicsBeginImageContext(bounds.size);

    CGContextRef context = UIGraphicsGetCurrentContext();

    UIImageOrientation orient = image.imageOrientation;

    if (orient == UIImageOrientationRight || orient == UIImageOrientationLeft) {
        CGContextScaleCTM(context, -scaleRatio, scaleRatio);
        CGContextTranslateCTM(context, -height, 0);
    }
    else {
        CGContextScaleCTM(context, scaleRatio, -scaleRatio);
        CGContextTranslateCTM(context, 0, -height);
    }

    CGContextConcatCTM(context, transform);

    CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, width, height), imgRef);
    UIImage *imageCopy = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return imageCopy;
}

Answer 2

This is a really old thread, but here's how to do it currently in case anyone also has this issue.

UIWindow *keyWindow = [[UIApplication sharedApplication] keyWindow];

CGRect rect = [keyWindow bounds];
UIGraphicsBeginImageContext(rect.size);

CGContextRef context = UIGraphicsGetCurrentContext();
[keyWindow.layer renderInContext:context];

UIImage * image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return [[UIImage alloc] initWithCGImage:[image CGImage] scale:1 orientation:UIImageOrientationLeft];

If you want it rotated right, just replace UIImageOrientationLeft with UIImageOrientationRight