SynScrollViewObserverEffects
Description
SynScrollViewObserverEffects provides a set of observer effects for observing and reacting to scroll events on a UIScrollView. This library simplifies the process of implementing scroll-based animations and effects in your app.
Installation
You can install SynScrollViewObserverEffects through CocoaPods by adding the following line to your Podfile:
pod 'SynScrollViewObserverEffects'
Usage
Import
First, import the SynScrollViewObserverEffects module:
import SynScrollViewObserverEffects
Initializing
To use SynScrollViewObserverEffects, create an instance of SynScrollViewObserver and set it as the delegate of your UIScrollView.
let observer = SynScrollViewObserver()
scrollView.delegate = observer
Configuring Effects
SynScrollViewObserverEffects supports a variety of effects that can be applied to your UIScrollView. You can configure these effects through the observer’s properties.
FadeEffect
The FadeEffect fades in/out the content of your UIScrollView as it is being scrolled. To enable the effect, set the observer’s fadeEffectEnabled property to true.
observer.fadeEffectEnabled = true
ScaleEffect
The ScaleEffect scales the content of your UIScrollView as it is being scrolled. To enable the effect, set the observer’s scaleEffectEnabled property to true.
observer.scaleEffectEnabled = true
ParallaxEffect
The ParallaxEffect gives a parallax effect to your UIScrollView. To enable the effect, set the observer’s parallaxEffectEnabled property to true. You can also adjust the parallax intensity using the parallaxIntensity property (default is 0.2).
observer.parallaxEffectEnabled = true
observer.parallaxIntensity = 0.3
Customization
SynScrollViewObserverEffects provides customization options for each effect. You can adjust the behavior and appearance of each effect to suit your app’s design.
FadeEffect
You can customize the fade effect’s behavior by modifying the following properties:
- fadeEffectStartOffset – The offset at which the fade effect should start (default is 0.0).
- fadeEffectEndOffset – The offset at which the fade effect should end (default is 1.0).
- fadeEffectStartAlpha – The initial alpha value at the start offset (default is 1.0).
- fadeEffectEndAlpha – The final alpha value at the end offset (default is 0.0).
- fadeEffectEaseFunction – The easing function to be used for alpha interpolation (default is linear). You can choose from linear, easeIn, easeOut, and easeInOut.
ScaleEffect
You can customize the scale effect’s behavior by modifying the following properties:
- scaleEffectStartOffset – The offset at which the scale effect should start (default is 0.0).
- scaleEffectEndOffset – The offset at which the scale effect should end (default is 1.0).
- scaleEffectStartScale – The initial scale value at the start offset (default is 1.0).
- scaleEffectEndScale – The final scale value at the end offset (default is 0.5).
- scaleEffectEaseFunction – The easing function to be used for scale interpolation (default is easeOut). You can choose from linear, easeIn, easeOut, and easeInOut.
ParallaxEffect
You can customize the parallax effect’s behavior by modifying the following properties:
- parallaxEffectStartOffset – The offset at which the parallax effect should start (default is 0.0).
- parallaxEffectEndOffset – The offset at which the parallax effect should end (default is 1.0).
- parallaxEffectStartScale – The initial scale value at the start offset (default is 1.0).
- parallaxEffectEndScale – The final scale value at the end offset (default is 2.0).
- parallaxEffectEaseFunction – The easing function to be used for scale interpolation (default is linear). You can choose from linear, easeIn, easeOut, and easeInOut.
Examples
Here are some examples of how you can use SynScrollViewObserverEffects in your app:
Fading Navigation Bar
You can fade in/out your navigation bar as the UIScrollView is being scrolled.
let navigationBar = navigationController.navigationBar
observer.animationBlock = { scrollView, _ in
let offsetY = scrollView.contentOffset.y
let alpha = min(1.0, offsetY / navigationBar.frame.height)
navigationBar.alpha = alpha
}
Scaling Background Image
You can scale a background image as the UIScrollView is being scrolled.
let imageView = UIImageView(image: UIImage(named: "background.png"))
imageView.contentMode = .scaleAspectFill
scrollView.addSubview(imageView)
observer.animationBlock = { scrollView, _ in
let offsetY = scrollView.contentOffset.y
let scale = max(1.0, 1.0 + offsetY / imageView.frame.height)
imageView.transform = CGAffineTransform(scaleX: scale, y: scale)
}
Requirements
SynScrollViewObserverEffects has the following requirements:
- iOS 10.0+
- Xcode 11.0+
- Swift 5.0+
License
SynScrollViewObserverEffects is available under the MIT license. See the LICENSE file for more info.