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

• Swift 3.0
• iOS 8.0+
• Xcode 8+

The easiest way is through CocoaPods. Simply add the dependency to your Podfile and then pod install:

pod 'Agrume', :git => 'https://github.com/JanGorman/Agrume.git'

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

github "JanGorman/Agrume"

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

For just a single image it's as easy as

import Agrume

@IBAction func openImage(_ sender: AnyObject) {
  if let image = UIImage(named: "…") {
	let agrume = Agrume(image: image)
	agrume.showFrom(self)	
  }
}

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

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.

let agrume = Agrume(images: images, startIndex: indexPath.row, backgroundBlurStyle: .light)
agrume.didScroll = { [unowned self] index in
  self.collectionView?.scrollToItem(at: IndexPath(row: index, section: 0),
                                    at: [],
                                    animated: false)
}
agrume.showFrom(self)

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

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. I can recommend MapleBacon.

import Agrume
import MapleBacon

@IBAction func openURL(_ sender: AnyObject) {
  let agrume = Agrume(imageUrl: URL(string: "https://dl.dropboxusercontent.com/u/512759/MapleBacon.png")!, backgroundBlurStyle: .light)
	agrume.download = { url, completion in
	  ImageDownloader.downloadImage(url) { image in
		if let image = image {
		  completion(image)
		} else {
		  completion(nil)
		}
	}
  }
  agrume.showFrom(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 remember to call the completion
}

// Some other place
agrume.showFrom(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.showFrom(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.showFrom(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.showFrom(self)

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