// newWindow creates a new window with a random background color. It sets the
// WM_PROTOCOLS property to contain the WM_DELETE_WINDOW atom. It also sets
// up a ClientMessage event handler so that we know when to destroy the window.
// We also set up a mouse binding so that clicking inside a window will
// create another one.
func newWindow(X *xgbutil.XUtil) {
counter++
win, err := xwindow.Generate(X)
if err != nil {
log.Fatal(err)
}
// Get a random background color, create the window (ask to receive button
// release events while we're at it) and map the window.
bgColor := rand.Intn(0xffffff + 1)
win.Create(X.RootWin(), 0, 0, 200, 200,
xproto.CwBackPixel|xproto.CwEventMask,
uint32(bgColor), xproto.EventMaskButtonRelease)
// WMGracefulClose does all of the work for us. It sets the appropriate
// values for WM_PROTOCOLS, and listens for ClientMessages that implement
// the WM_DELETE_WINDOW protocol. When one is found, the provided callback
// is executed.
win.WMGracefulClose(
func(w *xwindow.Window) {
// Detach all event handlers.
// This should always be done when a window can no longer
// receive events.
xevent.Detach(w.X, w.Id)
mousebind.Detach(w.X, w.Id)
w.Destroy()
// Exit if there are no more windows left.
counter--
if counter == 0 {
os.Exit(0)
}
})
// It's important that the map comes after setting WMGracefulClose, since
// the WM isn't obliged to watch updates to the WM_PROTOCOLS property.
win.Map()
// A mouse binding so that a left click will spawn a new window.
// Note that we don't issue a grab here. Typically, window managers will
// grab a button press on the client window (which usually activates the
// window), so that we'd end up competing with the window manager if we
// tried to grab it.
// Instead, we set a ButtonRelease mask when creating the window and attach
// a mouse binding *without* a grab.
err = mousebind.ButtonReleaseFun(
func(X *xgbutil.XUtil, ev xevent.ButtonReleaseEvent) {
newWindow(X)
}).Connect(X, win.Id, "1", false, false)
if err != nil {
log.Fatal(err)
}
}
func main() {
// Connect to the X server using the DISPLAY environment variable.
X, err := xgbutil.NewConn()
if err != nil {
log.Fatal(err)
}
// Anytime the mousebind (keybind) package is used, mousebind.Initialize
// *should* be called once. In the case of the mousebind package, this
// isn't strictly necessary, but the 'Drag' features of the mousebind
// package won't work without it.
mousebind.Initialize(X)
// Before attaching callbacks, wrap them in a callback function type.
// The mouse package exposes two such callback types:
// mousebind.ButtonPressFun and mousebind.ButtonReleaseFun.
cb1 := mousebind.ButtonPressFun(
func(X *xgbutil.XUtil, e xevent.ButtonPressEvent) {
log.Println("Button press!")
})
// We can now attach the callback to a particular window and button
// combination. This particular example grabs a button on the root window,
// which makes it a global mouse binding.
// Also, "Mod4-1" typically corresponds to pressing down the "Super" or
// "Windows" key on your keyboard, and then pressing the left mouse button.
// The last two parameters are whether to make a synchronous grab and
// whether to actually issue a grab, respectively.
// (The parameters used here are the common case.)
// See the documentation for the Connect method for more details.
err = cb1.Connect(X, X.RootWin(), "Mod4-1", false, true)
// A mouse binding can fail if the mouse string could not be parsed, or if
// you're trying to bind a button that has already been grabbed by another
// client.
if err != nil {
log.Fatal(err)
}
// We can even attach multiple callbacks to the same button.
err = mousebind.ButtonPressFun(
func(X *xgbutil.XUtil, e xevent.ButtonPressEvent) {
log.Println("A second handler always happens after the first.")
}).Connect(X, X.RootWin(), "Mod4-1", false, true)
if err != nil {
log.Fatal(err)
}
// Finally, if we want this client to stop responding to mouse events, we
// can attach another handler that, when run, detaches all previous
// handlers.
// This time, we'll show an example of a ButtonRelease binding.
err = mousebind.ButtonReleaseFun(
func(X *xgbutil.XUtil, e xevent.ButtonReleaseEvent) {
// Use mousebind.Detach to detach the root window
// from all ButtonPress *and* ButtonRelease handlers.
mousebind.Detach(X, X.RootWin())
mousebind.Detach(X, X.RootWin())
log.Printf("Detached all Button{Press,Release}Events from the "+
"root window (%d).", X.RootWin())
}).Connect(X, X.RootWin(), "Mod4-Shift-1", false, true)
if err != nil {
log.Fatal(err)
}
// Finally, start the main event loop. This will route any appropriate
// ButtonPressEvents to your callback function.
log.Println("Program initialized. Start pressing mouse buttons!")
xevent.Main(X)
}