How to fix translucent toolbar screenshot showing as black in iOS 7?

问题

My top and bottom toolbars are showing as black when in the app they show as light gray. I'm assuming it may have something to do with the default 'translucency checkbox' I found in the .storyboard, attributes inspector of the toolbar?

I'm using a UIActivityViewController to shoot this image out in an email. Here's the code for grabbing the screenshot:

// Grab a screenshot
UIGraphicsBeginImageContext(self.view.bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *imageToShare = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

回答1:

Solution found here: iOS: what's the fastest, most performant way to make a screenshot programmatically?

Seems like this should be a factory method provided by an Apple framework though. I'm putting this a Utils.h/.m class:

+ (UIImage *)screenshot
{
    CGSize imageSize = CGSizeZero;

    UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
    if (UIInterfaceOrientationIsPortrait(orientation)) {
        imageSize = [UIScreen mainScreen].bounds.size;
    } else {
        imageSize = CGSizeMake([UIScreen mainScreen].bounds.size.height, [UIScreen mainScreen].bounds.size.width);
    }

    UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);
    CGContextRef context = UIGraphicsGetCurrentContext();
    for (UIWindow *window in [[UIApplication sharedApplication] windows]) {
        CGContextSaveGState(context);
        CGContextTranslateCTM(context, window.center.x, window.center.y);
        CGContextConcatCTM(context, window.transform);
        CGContextTranslateCTM(context, -window.bounds.size.width * window.layer.anchorPoint.x, -window.bounds.size.height * window.layer.anchorPoint.y);
        if (orientation == UIInterfaceOrientationLandscapeLeft) {
            CGContextRotateCTM(context, M_PI_2);
            CGContextTranslateCTM(context, 0, -imageSize.width);
        } else if (orientation == UIInterfaceOrientationLandscapeRight) {
            CGContextRotateCTM(context, -M_PI_2);
            CGContextTranslateCTM(context, -imageSize.height, 0);
        } else if (orientation == UIInterfaceOrientationPortraitUpsideDown) {
            CGContextRotateCTM(context, M_PI);
            CGContextTranslateCTM(context, -imageSize.width, -imageSize.height);
        }
        if ([window respondsToSelector:@selector(drawViewHierarchyInRect:afterScreenUpdates:)]) {
            [window drawViewHierarchyInRect:window.bounds afterScreenUpdates:YES];
        } else {
            [window.layer renderInContext:context];
        }
        CGContextRestoreGState(context);
    }

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

回答2:

You should probably set the color you on your layer before rendering it:

self.view.backgroundColor = [UIColor whateverColorYouWant];
UIGraphicsBeginImageContext(self.view.bounds.size); 
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()]; 
UIImage *imageToShare = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Take a look at that anwser

来源：https://stackoverflow.com/questions/21863223/how-to-fix-translucent-toolbar-screenshot-showing-as-black-in-ios-7

标签

ios7