獲取快照

- (UIImage *)getSnapshot 
{      
UIScreen *screen = [UIScreen mainScreen];
CGRect bounds = [self.view bounds];
UIGraphicsBeginImageContextWithOptions(bounds.size, false, screen.scale);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(context, kCGInterpolationHigh);
[self.view drawViewHierarchyInRect:bounds afterScreenUpdates:YES];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();  
return image;
}

迅速

var screenshot: UIImage
{
UIGraphicsBeginImageContext(self.bounds.size);
let context = UIGraphicsGetCurrentContext();
self.layer.render(in: context)
let screenShot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return screenShot
}