wm/vend/xgbutil/_examples/simple-keybinding/main.go

83 lines
3.0 KiB
Go

// Example simple-keybinding shows how to grab keys on the root window and
// respond to them via callback functions. It also shows how to remove such
// callbacks so that they no longer respond to the key events.
// Note that more documentation can be found in the keybind package.
package main
import (
"log"
"github.com/jezek/xgbutil"
"github.com/jezek/xgbutil/keybind"
"github.com/jezek/xgbutil/xevent"
)
func main() {
// Connect to the X server using the DISPLAY environment variable.
X, err := xgbutil.NewConn()
if err != nil {
log.Fatal(err)
}
// Anytime the keybind (mousebind) package is used, keybind.Initialize
// *should* be called once. It isn't strictly necessary, but allows your
// keybindings to persist even if the keyboard mapping is changed during
// run-time. (Assuming you're using the xevent package's event loop.)
keybind.Initialize(X)
// Before attaching callbacks, wrap them in a callback function type.
// The keybind package exposes two such callback types: keybind.KeyPressFun
// and keybind.KeyReleaseFun.
cb1 := keybind.KeyPressFun(
func(X *xgbutil.XUtil, e xevent.KeyPressEvent) {
log.Println("Key press!")
})
// We can now attach the callback to a particular window and key
// combination. This particular example grabs a key on the root window,
// which makes it a global keybinding.
// Also, "Mod4-j" typically corresponds to pressing down the "Super" or
// "Windows" key on your keyboard, and then pressing the letter "j".
// N.B. This approach works by issuing a passive grab on the window
// specified. To respond to Key{Press,Release} events without a grab, use
// the xevent.Key{Press,Release}Fun callback function types instead.
err = cb1.Connect(X, X.RootWin(), "Mod4-j", true)
// A keybinding can fail if the key string could not be parsed, or if you're
// trying to bind a key that has already been grabbed by another client.
if err != nil {
log.Fatal(err)
}
// We can even attach multiple callbacks to the same key.
err = keybind.KeyPressFun(
func(X *xgbutil.XUtil, e xevent.KeyPressEvent) {
log.Println("A second handler always happens after the first.")
}).Connect(X, X.RootWin(), "Mod4-j", true)
if err != nil {
log.Fatal(err)
}
// Finally, if we want this client to stop responding to key events, we
// can attach another handler that, when run, detaches all previous
// handlers.
// This time, we'll show an example of a KeyRelease binding.
err = keybind.KeyReleaseFun(
func(X *xgbutil.XUtil, e xevent.KeyReleaseEvent) {
// Use keybind.Detach to detach the root window
// from all KeyPress *and* KeyRelease handlers.
keybind.Detach(X, X.RootWin())
log.Printf("Detached all Key{Press,Release}Events from the "+
"root window (%d).", X.RootWin())
}).Connect(X, X.RootWin(), "Mod4-Shift-q", true)
if err != nil {
log.Fatal(err)
}
// Finally, start the main event loop. This will route any appropriate
// KeyPressEvents to your callback function.
log.Println("Program initialized. Start pressing keys!")
xevent.Main(X)
}