Layout Algorithms: Facebook | Google Plus | Lightbox | Lightbox Android | 500px

Lightbox.com has a really interesting image layout algorithm. We're going to see how it works and its best use case.

How does it work?

Column based

The algorithm is column based. You pick a number of columns at the beginning. Then every time you want to layout an image, you just place it to the smallest column.

Some facts about this layout: All the images here have the same width. The order is not particularly respected. The end of the stream is not properly aligned.

Bigger Images

The interesting part of Lightbox layout is the ability to make some images bigger. When you are about to layout an image, you look at the height of the neighbor columns. If the column has the same size, then you can to extend the image to take the width of both columns.

Beating the Odds

Having two adjacent columns with the exact same size is rarely going to happen in practice. In order to solve this situation we are going to cheat a little. We draw an invisible grid and every time an image doesn't perfectly align with the grid, we crop it to the nearest line.

The bigger the grid is, the more opportunity you will have to make bigger images but at the same time, the more you will crop your images.

When to make images bigger?

This might be counter intuitive but you don't want to make images bigger every time the opportunity present itself. Every time you make an image bigger, it is going to preserve two adjacent columns of the same height. If you keep adding bigger images on top of those two column, you essentially created a column that has twice the width.

Using a column based layout implies that landscape images are much smaller than the portrait ones. In order to restore balance, Lightbox uses the following heuristic. If the image is landscape, then it has 60% chance to be made bigger, only 10% when it is a portrait.

Conclusion

Check out the Demo!

This layout is very good for random collection of images in an infinite stream. Here's a little Pro/Con to know if this technique will fit your needs.

Pros:

  • Can make some images bigger
  • No holes
  • Need to store only two dimensions per image
  • Arbitrary number of columns

Cons:

  • Landscape images are much smaller than portrait ones
  • Images that can be bigger is very arbitrary
  • Small cropping
  • Order is not respected
  • End of stream is not well aligned

Some other implementations I found on the internet:

If you liked this article, you might be interested in my Twitter feed as well.
 
 

Related Posts

  • August 13, 2012 Image Layout Algorithm – Facebook (1)
    Layout Algorithms: Facebook | Google Plus | Lightbox | Lightbox Android | 500px For the redesign of the Photo Section of Facebook we wanted to highlight some photos by making them bigger. It all started with the following mock by Andy Chung: Layout Alternated Blocks My […]
  • August 14, 2012 Image Layout Algorithm – Facebook – Reordering (2)
    In this article, we are going to see how to support dynamic updates to Facebook Image Layout Algorithm. Beware, this is not an easy task and there are many special cases to handle :) Making images bigger To make images bigger we just run the algorithm all over again with the new […]
  • June 8, 2012 CSS – Absolute position taking into account padding (6)
    When looking at the code of Lightbox.com I remarked that they are not using top and left in order to position their images but margin-top and margin-left. I've been wondering why for some time and finally found the reason. It is a way to position absolutely elements in a container and […]
  • April 5, 2012 Climb – Property-based dispatch in functional languages (1)
    ELS Presentation | A Generic and Dynamic Approach to Image Processing | Chaining Operators & Component Trees | Property-based dispatch in functional languages This is the third (and last) presentation about my work on Climb at the LRDE. During the first one I tackled genericity […]
  • July 13, 2012 Image Layout Algorithm – Google Plus (18)
    Layout Algorithms: Facebook | Google Plus | Lightbox | Lightbox Android | 500px Google Plus has a really nice image gallery. They somehow managed to display all the photos without cropping, without reordering and without any holes. We are going to see how they did it in this blog […]