Add example

examples/keypress/main.go

@@ -0,0 +1,100 @@
+// Example keypress is xgbutil/_examples/keypress-english modified to
+// demonstrate the functionality in this module.
+package main
+
+import "log"
+import "flag"
+import "unicode"
+import "github.com/jezek/xgbutil"
+import "github.com/jezek/xgb/xproto"
+import "github.com/jezek/xgbutil/xevent"
+import "github.com/jezek/xgbutil/xwindow"
+import "github.com/jezek/xgbutil/keybind"
+import "git.tebibyte.media/sashakoshka/xgbkb"
+
+var flagRoot = false
+
+func init() {
+	log.SetFlags(0)
+	flag.BoolVar(&flagRoot, "root", flagRoot,
+		"When set, the keyboard will be grabbed on the root window. "+
+			"Make sure you have a way to kill the window created with "+
+			"the mouse.")
+	flag.Parse()
+}
+
+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.)
+	// It also handles the case when your modifier map is changed.
+	keybind.Initialize(X)
+
+	// xgbkb must also be initialized before use, but only after keybind has
+	// been initialized.
+	xgbkb.Initialize(X)
+
+	// Create a new window. We will listen for key presses and translate them
+	// only when this window is in focus. (Similar to how `xev` works.)
+	win, err := xwindow.Generate(X)
+	if err != nil {
+		log.Fatalf("Could not generate a new window X id: %s", err)
+	}
+	win.Create(X.RootWin(), 0, 0, 500, 500, xproto.CwBackPixel, 0xffffffff)
+
+	// Listen for Key{Press,Release} events.
+	win.Listen(xproto.EventMaskKeyPress, xproto.EventMaskKeyRelease)
+
+	// Map the window.
+	win.Map()
+
+	// Notice that we use xevent.KeyPressFun instead of keybind.KeyPressFun,
+	// because we aren't trying to make a grab *and* because we want to listen
+	// to *all* key press events, rather than just a particular key sequence
+	// that has been pressed.
+	wid := win.Id
+	if flagRoot {
+		wid = X.RootWin()
+	}
+	xevent.KeyPressFun(
+		func(X *xgbutil.XUtil, e xevent.KeyPressEvent) {
+			symbol, character := xgbkb.KeycodeToKeysym( e.Detail, e.State)
+			if unicode.IsPrint(character) {
+				log.Printf("0x%04X | '%s'\n", symbol, string(character))
+			} else {
+				log.Printf("0x%04X |\n", symbol)
+			}
+
+			if keybind.KeyMatch(X, "Escape", e.State, e.Detail) {
+				if e.State&xproto.ModMaskControl > 0 {
+					log.Println("Control-Escape detected. Quitting...")
+					xevent.Quit(X)
+				}
+			}
+		}).Connect(X, wid)
+
+	// If we want root, then we take over the entire keyboard.
+	if flagRoot {
+		if err := keybind.GrabKeyboard(X, X.RootWin()); err != nil {
+			log.Fatalf("Could not grab keyboard: %s", err)
+		}
+		log.Println("WARNING: We are taking *complete* control of the root " +
+			"window. The only way out is to press 'Control + Escape' or to " +
+			"close the window with the mouse.")
+	}
+
+	// Finally, start the main event loop. This will route any appropriate
+	// KeyPressEvents to your callback function.
+	log.Println("Program initialized. Start pressing keys!")
+	log.Println("Keysym | Rune")
+	log.Println("------ | ----")
+	xevent.Main(X)
+}