In this chapter, we explored the details of the GTK+ toolkit and how it is made available to Go through go-GTK. We looked at how to get it set up on macOS, Windows, and Linux and how the applications look and behave exactly the same across these platforms. We explored the API design, its various components, and how its event driven model is exposed to developers.

We then returned to the GoMail application from Chapter 4, Walk - Building Graphical Windows Applications, and Chapter 5, andlabs UI - Cross-Platform Native UIs, rebuilding it using the Go-GTK library. As the API provides access to most GTK+ features, we found that the application looks more complete than the GTK+ based application created by the Linux driver within andlabs UI used in Chapter 5, andlabs UI - Cross-Platform Native UIs. We implemented some basic thread and signal handling within the application to handle user input and background events. Lastly, we explored how the powerful GTK+ theme engine could style the created application user interface.

By now, you should be familiar with the Go-GTK library, and how it leverages the underlying GTK+ toolkit and allows the quick development of GUI applications with Go. These applications will differ from the operating system standard look and feel, but are close to standard application design and so should be familiar to most users. If the interface widget design or API wasn't quite what you were looking for, then read the next chapter, where we look at an alternative to GTK, the Qt framework.