Question

I got this screenshot method from Apple’s website:

- (UIImage*)screenshot 
{
    // Create a graphics context with the target size
    // On iOS 4 and later, use UIGraphicsBeginImageContextWithOptions to take the scale into consideration
    // 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;
}

It works like a charm, but I have a small problem with it: I don’t want the status bar to show app in my screenshots. What should I modify? I honestly have no idea what I should modify here because I have never worked with the CG framework too much. I was thinking in substracting 20 (the status bar heigh) from something that gets a “y” property, but I don’t want to break this method. So what should I modify to take an screenshot of everything but the status bar? Again, I apologise if this is a real stupid problem, but I really have no idea of what I would be doing shall I try to modify it myself.

Answer 1

I just figured it out. Indeed, I just substracted 20 from a “y” property:

So instead of this:

CGContextTranslateCTM(context, [window center].x, [window center].y);

I did this:

CGContextTranslateCTM(context, [window center].x, [window center].y - 20);

There’s probably a better way to do it, but this one served me very well.