TRMosaicLayout 1.0.0

TRMosaicLayout 1.0.0

LangLanguage SwiftSwift
License MIT
ReleasedLast Release Oct 2016
SwiftSwift Version 3.0
SPMSupports SPM

Maintained by Vincent Le.

  • By
  • Vincent Le


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A mosaic collection view layout inspired by Lightbox’s Algorithm. This is a swift implementation/extension of @fmitech’s FMMosaicLayout. The standard UICollectionViewFlowLayout can be a boring presentation in your app, but TRMosaicLayout is a simple feature that will engage your users with your eyecatching content. If you don’t believe me, checkout Snapchat’s app and their awesome layout in their Discover feed.

TRMosaicLayout implementation

Similar implementation used by @snapchat

Why use this

  • TRMosaicLayout is great for displaying images that are in portrait or have a similar aspect ratio
  • Examples
    • Movie posters
    • Book covers
    • Magazines
    • News articles



  1. Download and drop /TRMosaicLayoutfolder in your project.
  2. Congratulations!


Create a subclass of UICollectionViewController

import TRMosaicLayout

class TRCollectionViewController: UICollectionViewController {
  override func viewDidLoad() {

      let mosaicLayout = TRMosaicLayout()
      self.collectionView?.collectionViewLayout = mosaicLayout
      mosaicLayout.delegate = self

Extend your subclass of UICollectionViewController with TRMosaicLayoutDelegate

extension TRCollectionViewController: TRMosaicLayoutDelegate {

  func collectionView(collectionView:UICollectionView, mosaicCellSizeTypeAtIndexPath indexPath:NSIndexPath) -> TRMosaicCellType {
    // I recommend setting every third cell as .Big to get the best layout
    return indexPath.item % 3 == 0 ? TRMosaicCellType.Big : TRMosaicCellType.Small

  func collectionView(collectionView:UICollectionView, layout collectionViewLayout: TRMosaicLayout, insetAtSection:Int) -> UIEdgeInsets {
    return UIEdgeInsets(top: 3, left: 3, bottom: 3, right: 3)

  func heightForSmallMosaicCell() -> CGFloat {
    return 150


The cell’s aren’t aligned properly

  • Make sure the views you are adding to the cell have the correct frame
  let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath)
  let imageView = UIImageView(image: image)
  imageView.frame = cell.frame
  cell.backgroundView = imageView
  return cell

Getting a nil while unwrapping error

  • Make sure you set the delegate of TRMosaicLayout to your collectionViewController
  • mosaicLayout.delegate = self

Something else isn’t working properly

  • Use github’s issue reporter on the right, this will you be your best bet as I’m on Github fairly regularly
  • Send me an email [email protected]

Release History

  • 0.1.0 First release on CocoaPods


I am happy to accept any open contributions. Just fork this project, make the changes and submit a pull request.


Vincent Le, [email protected]


TRMosaicLayout is available under the MIT license. See the LICENSE file for more info.