iPhone 横向视图屏幕截图

Question

我正在横向模式下运行该应用程序。 我需要注意什么才能使拍摄的屏幕截图也处于横向模式。

我在 iPhone 应用程序中使用以下代码，底部有标签栏并拍摄屏幕截图，但它始终仅处于纵向模式。为什么？

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

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

Answer 1

我之前的回答是不正确的。我已经研究过这个问题，并且我有一个横向右屏幕截图的答案。这会将横向右侧屏幕截图正确保存到相机胶卷中。我还没有尝试过左风景。

这是另一个 stackoverflow 问题中提供的答案的变体此处。该答案的问题在于屏幕截图始终具有 UIImageOrientationUp 的 imageOrientation（只读）。因此，我们有责任了解方向是什么并适当地改变它。

我希望这有帮助。如果这适用于横向左侧，或者您得到适用于横向左侧的变体，请发布它。

 - (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

这是一个非常古老的线程，但目前以下是如何执行此操作，以防有人也遇到此问题。

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];

如果你想让它向右旋转，只需将 UIImageOrientationLeft 替换为 UIImageOrientationRight