README
¶
gtk4
Drive GTK4 from pure Go with CGO_ENABLED=0 — windows, the common
controls, GObject signals and the GLib main loop — over
ebitengine/purego.
It is the Linux sibling of go-macos/objc:
the shared native-toolkit bridge a go-widgets
host backend embeds real controls through, so a pixel-drawn app can inlay a real
GtkEntry, GtkButton or secure field over its own rendering.
ok, err := gtk4.Init()
// win := gtk4.WindowNew(); win.SetTitle("…"); win.SetDefaultSize(360, 200)
// fixed := gtk4.FixedNew() // the overlay container
// e := gtk4.EntryNew(); e.SetVisibility(false) // a password field
// b := gtk4.ButtonNewWithLabel("OK")
// b.Connect("clicked", func() { … }) // a GObject signal, as a Go closure
// fixed.Put(e, 10, 10); fixed.Put(b, 10, 44); win.SetChild(fixed); win.Present()
No cgo
libgtk-4, libgobject-2.0 and libglib-2.0 are dlopen'd by soname and
every entry point is resolved with purego.RegisterLibFunc. A GObject signal
reaches Go through a purego.NewCallback, retained for the process life (GTK
holds the C pointer). The package links with no cgo and cross-compiles like any
other Go code.
What it binds
Init · WindowNew (+ SetTitle/SetDefaultSize/SetChild/Present) ·
FixedNew (+ Put/Move — absolute overlay positioning) · ButtonNewWithLabel
(+ SetLabel) · EntryNew (+ SetVisibility for a secure field) ·
CheckButtonNewWithLabel (+ Active/SetActive; grouped check buttons are GTK
radios) · LabelNew · Text/SetText (GtkEditable) · SetSizeRequest ·
SetVisible · Unparent · Connect (signals) · MainLoop (Run/Quit) ·
IdleAdd (marshal onto the GTK thread).
Platform
Linux only — this is the GTK path; a go-widgets host uses AppKit/Win32 on
macOS/Windows. Off Linux the package still compiles (a consumer cross-compiles
without a build tag) and every constructor's Init returns
ErrUnsupported, so
nothing is a build-time surprise. It needs only the runtime libgtk-4
(libgtk-4-1 on Debian/Ubuntu) — no -dev package.
Testing
CI builds it on every platform and runs a live test against real GTK4 under a
headless X server (Xvfb) — creating a window, entry, secure field, button and
check button, round-tripping their values, and proving a changed signal reaches
Go through the main loop.
License
BSD-3-Clause. See LICENSE.
Documentation
¶
Overview ¶
Package gtk4 binds the parts of GTK4 a windowing toolkit needs — windows, the common controls, GObject signals and the GLib main loop — from pure Go with CGO_ENABLED=0, over github.com/ebitengine/purego. It is the Linux sibling of github.com/go-macos/objc: the shared native-toolkit bridge a go-widgets host backend embeds real controls through.
It links no cgo: libgtk-4, libgobject-2.0 and libglib-2.0 are dlopen'd by soname and every entry point is resolved with purego.RegisterLibFunc, exactly as the feasibility spike proved on a stock Linux GTK4. A GObject signal reaches Go through a purego.NewCallback, so a control's clicks and edits are ordinary Go closures.
Index ¶
- Variables
- func IdleAdd(fn func())
- func Init() (ok bool, err error)
- type MainLoop
- type Widget
- func (w Widget) Active() bool
- func (w Widget) Connect(signal string, fn func()) uint64
- func (f Widget) Move(child Widget, x, y float64)
- func (w Widget) Present()
- func (f Widget) Put(child Widget, x, y float64)
- func (w Widget) SetActive(on bool)
- func (w Widget) SetChild(child Widget)
- func (w Widget) SetDefaultSize(width, height int)
- func (w Widget) SetLabel(label string)
- func (w Widget) SetSizeRequest(width, height int)
- func (w Widget) SetText(s string)
- func (w Widget) SetTitle(title string)
- func (w Widget) SetVisibility(vis bool)
- func (w Widget) SetVisible(vis bool)
- func (w Widget) Text() string
- func (w Widget) Unparent()
Constants ¶
This section is empty.
Variables ¶
var ErrUnsupported = errors.New("gtk4: only available on Linux")
ErrUnsupported is returned by Init on any platform without GTK4 (everything but Linux). It is defined on every platform so a portable consumer can test for it with errors.Is.
Functions ¶
Types ¶
type Widget ¶
type Widget uintptr
A Widget is a GTK widget — a GObject pointer. The zero value is the null widget. Methods on it are thin wrappers over the C API.
func ButtonNewWithLabel ¶
ButtonNewWithLabel creates a push button.
func CheckButtonNewWithLabel ¶
CheckButtonNewWithLabel creates a labelled check button. GTK check buttons that share a group act as radios; a host groups them for a NativeRadio.
func EntryNew ¶
func EntryNew() Widget
EntryNew creates a single-line text entry. Call SetVisibility(false) for a secure (password) entry.
func FixedNew ¶
func FixedNew() Widget
FixedNew creates a GtkFixed — the container a host overlays native controls in at absolute positions, over the pixel drawing area.
func (Widget) Connect ¶
Connect wires a GObject signal (e.g. "clicked", "changed") to a Go func. The callback keeps the widget's value reachable through its own accessors, so the zero-argument closure is enough for the control signals a host cares about. The returned handler id is GObject's; a host rarely needs it.
The callback is retained for the process life (like the go-macos target classes): GTK holds a C pointer to it, and letting Go collect it would leave a dangling call.
func (Widget) SetDefaultSize ¶
func (Widget) SetSizeRequest ¶
SetSizeRequest fixes a widget's size (a host sizes controls to the region it laid out).
func (Widget) SetVisibility ¶
func (Widget) SetVisible ¶
SetVisible shows or hides a widget in place.
Source Files