pwiecz/go-fltk
GitHub: pwiecz/go-fltk
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# go-fltk
[](https://pkg.go.dev/github.com/pwiecz/go-fltk)
A simple wrapper around FLTK 1.4 library, which is a lightweight GUI library which allows creating small, self-contained and fast gui applications.
## Status
The library is only a partial wrapper. New functions are being added as the are demanded by the users.
## Requirements
For building go-fltk, besides Golang compiler, you will also need a C++11 compiler, such as GCC or Clang on Linux, MinGW on Windows and XCode on MacOS.
go-fltk comes with prebuilt FLTK libraries for some architectures (linux/amd64, windows/amd64), but you can easily rebuild them yourself
or build them for other architectures.
To build FLTK libraries for your platform it should be enough to call `go generate` from the root of the go-fltk source tree.
If the build procedure doesn't work for you, you can modify `fltk-build.sh` or `fltk-build.bat` yourself or ask a question on `https://github.com/pwiecz/go-fltk/discussions`.
For running programs built using go-fltk you will need some system libs which are normally available on operating systems with a graphical user interfaces:
- Windows: No external dependencies, besides a (for mingw64)
- MacOS: No external dependencies
- Linux (and other Unix systems - not tested): You need:
- X11
- Xrender
- Xcursor
- Xfixes
- Xext
- Xft
- Xinerama
- XKBCommon
- Wayland
- libdecor
- DBus
- OpenGL
## Usage
package main
import "github.com/pwiecz/go-fltk"
func main() {
win := fltk.NewWindow(400, 300)
win.SetLabel("Main Window")
btn := fltk.NewButton(160, 200, 80, 30, "Click")
btn.SetCallback(func() {
btn.SetLabel("Clicked")
})
win.End()
win.Show()
fltk.Run()
}
Widgets are created using the `fltk.New` functions, modified for whatever widget you're instantiating.
Function and method names resemble the original C++ names, while however, following the Golang convention of PascalCase.
Setter methods are also preceded by a `Set` prefix.
## Styling
FLTk offers 4 builtin schemes:
- base (default)
- gtk+
- gleam
- plastic
These can be set using `fltk.SetScheme("gtk+")` for example.
FLTK also allows custom styling of your widgets:
package main
import (
"strconv"
"github.com/pwiecz/go-fltk"
)
// FLTK uses an RGBI color representation, the I is an index into FLTK's color map
// Passing 00 as I will use the RGB part of the value
const GRAY = 0x75757500
const LIGHT_GRAY = 0xeeeeee00
const BLUE = 0x42A5F500
const SEL_BLUE = 0x2196F300
const WIDTH = 600
const HEIGHT = 400
func main() {
curr := 0
fltk.InitStyles()
win := fltk.NewWindow(WIDTH, HEIGHT)
win.SetLabel("Flutter-like")
win.SetColor(fltk.WHITE)
bar := fltk.NewBox(fltk.FLAT_BOX, 0, 0, WIDTH, 60, " FLTK App!")
bar.SetDrawHandler(func() { // Shadow under the bar
fltk.DrawBox(fltk.FLAT_BOX, 0, 0, WIDTH, 63, LIGHT_GRAY)
})
bar.SetAlign(fltk.ALIGN_INSIDE | fltk.ALIGN_LEFT)
bar.SetLabelColor(255) // this uses the index into the color map, here it's white
bar.SetColor(BLUE)
bar.SetLabelSize(22)
text := fltk.NewBox(fltk.NO_BOX, 250, 180, 100, 40, "You have pushed the button this many times:")
text.SetLabelSize(18)
text.SetLabelFont(fltk.TIMES)
count := fltk.NewBox(fltk.NO_BOX, 250, 180+40, 100, 40, "0")
count.SetLabelSize(36)
count.SetLabelColor(GRAY)
btn := fltk.NewButton(WIDTH-100, HEIGHT-100, 60, 60, "@+6plus") // this translates into a plus sign
btn.SetColor(BLUE)
btn.SetSelectionColor(SEL_BLUE)
btn.SetLabelColor(255)
btn.SetBox(fltk.OFLAT_BOX)
btn.ClearVisibleFocus()
btn.SetCallback(func() {
curr += 1
count.SetLabel(strconv.Itoa(curr))
})
win.End()
win.Show()
fltk.Run()
}
Label attributes can be seen [here](https://www.fltk.org/doc-1.4/common.html#common_labels)
## Resources
- [Link](https://www.fltk.org/doc-1.4/index.html) to the official FLTK 1.4 documentation.
- [Link](https://pkg.go.dev/github.com/pwiecz/go-fltk) to go-fltk documentation.