Description

UIScrollView category to center content, enable additional zoom gestures and add getters for animated properties.

This category adds properties to enable and configure:

• Centering the content view, even when zooming out and having the UIScrollView bouncing. This also works for the view returned by -viewForZoomingInScrollView: of the UIScrollViewDelegate when zooming.

• Double-tapping to zoom in, two-finger-tapping to zoom out and one-finger-zooming (see BDDROneFingerZoomGestureRecognizer). Properties to access the gesture recognizers are provided.

Additionally, this category adds zoomScale, contentOffset and contentSize getters that return correct values when an animation is running on the UIScrollView. These new properties are not KVO compliant but can be polled repeatedly.
This is especially useful if you use an UIScrollView in your OpenGL View to scroll/zoom content: In your game loop you just poll the values to position and scale your rendered content.

For more info see the header.

Installation

Simply add the files in the UIScrollView+BDDRScrollViewAdditions.h and UIScrollView+BDDRScrollViewAdditions.m to your project or add BDDRScrollViewAdditions to your Podfile if you're using CocoaPods.

To run the example project clone the repo and run pod install in the Example folder.

Reasons for Existence

• Centering the content view is not done by default.

• By default there is no support for double-tap-zoom-in, two-finger-zoom-out or one-finger-zoom gestures.

• UIScrollView defines zoomScale, contentOffset and contentSize but these properties don't always return the correct values when UIScrollView is animating, for example when zoomBouncing is YES.

Contact

Follow @bddckr on Twitter.

Copyright and License

Copyright (c) 2013 Christopher - Marcel Böddecker
Licensed under The MIT License (MIT).