An iOS image viewer written in Swift with support for multiple images.

• Swift 4.2 (for Swift 3 support, use version 3.x)
• iOS 9.0+
• Xcode 9+

The easiest way is via CocoaPods. Add the dependency to your Podfile and then run pod install:

pod "Agrume"

Or Carthage. Add the dependency to your Cartfile and then run carthage update:

github "JanGorman/Agrume"

There are multiple ways you can use the image viewer (and the included sample project shows them all).

For just a single image it's as easy as

import Agrume

@IBAction func openImage(_ sender: Any) {
  let agrume = Agrume(image: UIImage(named: "…")!)
  agrume.show(from: self)
}

You can also pass in a URL and Agrume will take care of the download for you.

Agrume has different background configurations. You can have it blur the view it's covering or supply a background color:

let agrume = Agrume(image: UIImage(named: "…")!, background: .blurred(.regular))
// or
let agrume = Agrume(image: UIImage(named: "…")!, background: .colored(.green))

If you're displaying a UICollectionView and want to add support for zooming, you can also call Agrume with an array of either images or URLs.

// In case of an array of [UIImage]:
let agrume = Agrume(images: images, startIndex: indexPath.item, background: .blurred(.light))
// Or an array of [URL]:
// let agrume = Agrume(urls: urls, startIndex: indexPath.item, background: .blurred(.light))

agrume.didScroll = { [unowned self] index in
  self.collectionView.scrollToItem(at: IndexPath(item: index, section: 0), at: [], animated: false)
}
agrume.show(from: self)

This shows a way of keeping the zoomed library and the one in the background synced.

Agrume bundles SwiftyGif to display animated gifs. You use SwiftyGif's custom UIImage initializer:

let image = UIImage(gifName: "animated.gif")
let agrume = Agrume(image: image)
agrume.display(from: self)

// Or gif using data:

let image = UIImage(gifData: data)
let agrume = Agrume(image: image)

// Or multiple images:

let images = [UIImage(gifName: "animated.gif"), UIImage(named: "foo.png")] // You can pass both animated and regular images at the same time
let agrume = Agrume(images: images)

Remote animated gifs (i.e. using the url or urls initializer) are supported. Agrume does the image type detection and displays them properly. If using Agrume from a custom UIImageView you may need to rebuild the UIImage using the original data to preserve animation vs. using the UIImage instance from the image view.

Per default you dismiss the zoomed view by dragging/flicking the image off screen. You can opt out of this behaviour and instead display a close button. To match the look and feel of your app you can pass in a custom UIBarButtonItem:

// Default button that displays NSLocalizedString("Close", …)
let agrume = Agrume(image: UIImage(named: "…")!, .dismissal: .withButton(nil))
// Customise the button any way you like. For example display a system "x" button
let button = UIBarButtonItem(barButtonSystemItem: .stop, target: nil, action: nil)
button.tintColor = .red
let agrume = Agrume(image: UIImage(named: "…")!, .dismissal: .withButton(button))

The included sample app shows both cases for reference.

If you want to take control of downloading images (e.g. for caching), you can also set a download closure that calls back to Agrume to set the image. For example, let's use MapleBacon.

import Agrume
import MapleBacon

@IBAction func openURL(_ sender: Any) {
  let agrume = Agrume(url: URL(string: "https://dl.dropboxusercontent.com/u/512759/MapleBacon.png")!)
  agrume.download = { url, completion in
    Downloader.default.download(url) { image in
      completion(image)
    }
  }
  agrume.show(from: self)
}

Instead of having to define a handler on a per instance basis you can instead set a handler on the AgrumeServiceLocator. Agrume will use this handler for all downloads unless overriden on an instance as described above:

import Agrume

AgrumeServiceLocator.shared.setDownloadHandler { url, completion in
  // Download data, cache it and call the completion with the resulting UIImage
}

// Some other place
agrume.show(from: self)

For more dynamic library needs you can implement the AgrumeDataSource protocol that supplies images to Agrume. Agrume will query the data source for the number of images and if that number changes, reload it's scrolling image view.

import Agrume

let dataSource: AgrumeDataSource = MyDataSourceImplementation()
let agrume = Agrume(dataSource: dataSource)

agrume.show(from: self)

When showing the Agrume view controller, it'll default to taking a snapshot of the root view and blurring that. You can customize this behaviour by passing in a different view that it will blur and display:

let agrume = Agrume(image: image)
agrume.show(from: self, backgroundSnapshotVC: self)

You can customize the status bar appearance when displaying the zoomed in view. Agrume has a statusBarStyle property:

let agrume = Agrume(image: image)
agrume.statusBarStyle = .lightContent
agrume.show(from: self)

To get information about lifecycle events in Agrume you have the option to set a didDismiss handler. Similarly, to be informed about whenever the user scrolls through the image collection, there is a didScroll handler that is called with the current page index.

Agrume is released under the MIT license. See LICENSE for details