I have a view that I wish to present to the user in the standard way (sliding up from the bottom of the screen). About half this view is a transparent background and the bot
This is possible, and rockybalboa provides a solution to this issue in the forum post on raywenderlich.com:
iOS 8 UIModalPresentationCurrentContext is not transparent?
That solution being, quoting balboa's answer, in Objective-C:
Before iOS 8, you do this:
[backgroundViewController setModalPresentationStyle:UIModalPresentationCurrentContext];
[backgroundViewController presentViewController:_myMoreAppsViewController animated:NO completion:nil];
in iOS 8, you have to do this:
backgroundViewController.providesPresentationContextTransitionStyle = YES;
backgroundController.definesPresentationContext = YES;
[overlayViewController setModalPresentationStyle:UIModalPresentationOverCurrentContext];
To supplement the above code with the Swift equivalent:
backgroundViewController.providesPresentationContextTransitionStyle = true
backgroundController.definesPresentationContext = true
overlayViewController.modalPresentationStyle = .OverCurrentContext
Having implemented this using Xcode 6.3 beta 3 on iOS 8.1 with Swift 1.2, it works perfectly.
Just a comment that I viewed three different SO questions on this - the more recent now marked as duplicates - prior to finding and attempting the Ray Wenderlich forum solution.