Impressive is is a program that displays pdf presentation slides in style. If you use beamer to create presentation it is a must have.
Usually it works by running the command
impressive [path/filename] in the terminal/command promt. However, when you are stressed out and standing infront of a crowd, it is not always the fastest way to use the app.
In Elementary OS, one can modify the contextual file menu in pantheon-files by using the following code
Save the file with the extension
.contract in the contract folder, located in
/usr/share/contractor. After you save the file, the context menu will look like this when you write click on a pdf.