Cyclops is a small utility for Mac that aims to improve the experience when showing something on a secondary screen. Considering how dense is the retina display, selecting a single portion of a that display to be displayed as full screen in a secondary screen, is a reasonable solution.
A good example is live-coding, most of the time the secondary screen is a projector and the experience of live coding can be annoying due to the huge font and the duplication on a screen that has a low resolution. This is why I prototyped this utility after a nice chat with @icanzilb.
An example of how it works can be found on Vimeo.
This utility is still in alpha stage, contributions are welcomed and as soon as it's ready to be submitted to the store, I will make it available as free utility.
Current version works only on 10.11 El Capitan, the goal is to have it working on 10.10 Yosemite and higher.
Please feel free to contribute adding features via pull-requests, requesting features or opening issues to report bugs.