We have posted many times about how Fyne is designed to be easy to learn and fast to develop with. Presentations, meetups and our own conference have discussed the topic and it remains very important to the design of the toolkit.

That said there has not been much time put in to showing how to build more than simple demo applications, so it seemed wise to rectify the imbalance.

PixelEdit

And so in preparation for the Go developer room at FOSDEM we spent 4 hours creating a simple application. This application, PixelEdit, was designed to show how to use built in functionality, with a single custom widget to expand on the builtin components. As well as this it should have good test coverage and a well organised project showing how to keep separation of concerns in a graphical application context. And here is what 4 hours work created:

This basic user interface allows loading and saving pixel (PNG) images (using the Go “image” library), pick colours off the canvas and draw them back on with the pencil tool. Panning is provided by a ScrollContainer and the zooming is implemented by wrapping the canvas.Raster type in a custom widget.

Alongside this work a 67% code coverage was made possible by designing the code in small components and using the fyne.io/fyne/test utility package for automated testing Fyne apps. And let’s not forget that this will build and run across all the desktop and mobile platforms that Fyne supports.

You can find the full project at GitHub and you can install it using go get github.com/fyne-io/pixeledit. This is launched from the command line with a file parameter to open - once file open and save dialogs are implemented in Fyne we can improve that.

Check it out and feel free to share with us what apps you have built in surprisingly little time.