UIPresentationController+HorribleHacks.m

// This is more hacky than it should be!
- (UIModalPresentationStyle)pspdf_currentPresentationStyle {
    UIViewController *vc = self.presentedViewController.presentingViewController;
    
    if ([self respondsToSelector:@selector(adaptivePresentationStyleForTraitCollection:)]) {
        UIModalPresentationStyle const style = [self adaptivePresentationStyleForTraitCollection:vc.traitCollection];
        return (style == UIModalPresentationNone) ? self.presentationStyle : style;
    }

    // Before iOS 8.3 we have to fall back on assuming adaptivity is only possible for horizontally compact environments.
    // UIKit seems to do the same: UIModalPresentationPopover results in popover on iPhone 6 Plus in landscape.
    if (vc.traitCollection.horizontalSizeClass == UIUserInterfaceSizeClassCompact) {
        UIModalPresentationStyle style = self.adaptivePresentationStyle;
        if (style != UIModalPresentationNone) {
            return style;
        }
    }

    return self.presentationStyle;
}

- (BOOL)pspdf_isPopover {
    return self.pspdf_currentPresentationStyle == UIModalPresentationPopover;
}