Fyne: an easy to use UI toolkit and app API written in Go with OpenGL

About

Fyne is an easy to use UI toolkit and app API written in Go. We use OpenGL (through the go-gl and go-glfw projects) to provide cross platform graphics.

The 1.0 release is now out and we encourage feedback and requests for the next major releae :).

Getting Started

Fyne is designed to be really easy to code with, here are the steps to your first app.

Prerequisites

As Fyne uses CGo you will require a C compiler (typically gcc). If you don't have one set up the instructions at Compiling may help.

By default Fyne uses the gl golang bindings which means you need a working OpenGL configuration. Debian/Ubuntu based systems may need to also need to install the libgl1-mesa-dev and xorg-dev packages.

Using the standard go tools you can install Fyne's core library using:

go get fyne.io/fyne

Code

And then you're ready to write your first app!

package main

import (
	"fyne.io/fyne/widget"
	"fyne.io/fyne/app"
)

func main() {
	app := app.New()

	w := app.NewWindow("Hello")
	w.SetContent(widget.NewVBox(
		widget.NewLabel("Hello Fyne!"),
		widget.NewButton("Quit", func() {
			app.Quit()
		}),
	))

	w.ShowAndRun()
}

And you can run that simply as:

go run main.go

It should look like this:

Note that windows applications load from a command prompt by default, which means if you click an icon you may see a command window. To fix this add the parameters -ldflags -H=windowsgui to your run or build commands.

Scaling

Fyne is built entirely using vector graphics which means that applications that are written using it will scale to any value beautifully (not just whole number values). The default scale value is calculated from your screen's DPI - and if you move a window to another screen it will re-scale and adjust the window size accordingly! We call this "auto scaling" and it is designed to keep an app GUI the same size as you change monitor. You can override this behaviour by setting a specific scale using the FYNE_SCALE environment variable.

Standard size FYNE_SCALE=0.5 FYNE_SCALE=2.5

Themes

Fyne ships with two themes by default, "light" and "dark". You can choose which to use with the environment variable FYNE_THEME . The default is dark:

If you prefer a light theme then you could run:

FYNE_THEME=light go run main.go

It should then look like this:

Widget demo

To run a showcase of the features of fyne execute the following:

cd $GOPATH/src/fyne.io/fyne/cmd/fyne_demo/
go build
./fyne_demo

And you should see something like this (after you click a few buttons):

Or if you are using the light theme:

Declarative API

If you prefer a more declarative API then that is provided too. The following is exactly the same as the code above but in this different style.

package main

import (
	"fyne.io/fyne"
	"fyne.io/fyne/app"
	"fyne.io/fyne/widget"
)

func main() {
	app := app.New()

	w := app.NewWindow("Hello")
	w.SetContent(&widget.Box{Children: []fyne.CanvasObject{
		&widget.Label{Text: "Hello Fyne!"},
		&widget.Button{Text: "Quit", OnTapped: func() {
			app.Quit()
		}},
	}})

	w.ShowAndRun()
}

Examples

The main examples have been moved - you can find them in their own repository .