当相机在-iOS上时拍摄截图

Question

我正在开发一个AR应用程序，在我的项目中使用苹果的AVCam示例代码。我试图用下面的方法拍摄截图，这些方法我在这里已经找到了，但它们并不适用于我。有什么建议吗？谢谢。

    - (UIImage *) screenshot {
        UIWindow *window = [UIApplication sharedApplication].keyWindow;

        if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
            UIGraphicsBeginImageContextWithOptions(window.bounds.size, NO, [UIScreen mainScreen].scale);
        else
            UIGraphicsBeginImageContext(window.bounds.size);
        [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
        UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        NSData * data = UIImageJPEGRepresentation(image, 1.0);

        return [UIImage imageWithData:data];
    }

    - (UI

Image*)screenshot2
{
    // On iOS prior to 4, fall back to use UIGraphicsBeginImageContext
    CGSize imageSize = [[UIScreen mainScreen] bounds].size;
    if (NULL != UIGraphicsBeginImageContextWithOptions)
        UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);
    else
        UIGraphicsBeginImageContext(imageSize);

    CGContextRef context = UIGraphicsGetCurrentContext();

    // Iterate over every window from back to front
    for (UIWindow *window in [[UIApplication sharedApplication] windows])
    {
        if (![window respondsToSelector:@selector(screen)] || [window screen] == [UIScreen mainScreen])
        {
            // -renderInContext: renders in the coordinate space of the layer,
            // so we must first apply the layer's geometry to the graphics context
            CGContextSaveGState(context);
            // Center the context around the window's anchor point
            CGContextTranslateCTM(context, [window center].x, [window center].y);
            // Apply the window's transform about the anchor point
            CGContextConcatCTM(context, [window transform]);
            // Offset by the portion of the bounds left of and above the anchor point
            CGContextTranslateCTM(context,
                                  -[window bounds].size.width * [[window layer] anchorPoint].x,
                                  -[window bounds].size.height * [[window layer] anchorPoint].y);

            // Render the layer hierarchy to the current context
            [[window layer] renderInContext:context];

            // Restore the context
            CGContextRestoreGState(context);
        }
    }

    // Retrieve the screenshot image
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;
}

Answer 1

代码不工作，因为CALayer的renderInContext不呈现来自摄像机的内容。

请参阅以下参考资料：index.html

正如上面的链接所描述的，您可以：

1)使用相关的AVFoundation API (ref/doc/uid/DTS40010192)捕获摄像机的内容

2)然后将捕获的图像绘制到呈现UIKit元素的图形上下文中。