ui/app: (linux) separate xkb logic from wayland backend

Makes the Wayland backend more clean, and X11 might be able to reuse the xkb code. Signed-off-by: Elias Naur <mail@eliasnaur.com>
2026-07-01 15:45:38 +00:00 · 2019-09-26 13:01:51 +02:00
parent bbc0cebacf
commit 51cfb4e5c2
2 changed files with 263 additions and 200 deletions
@@ -10,13 +10,10 @@ import (
 	"fmt"
 	"image"
 	"math"
-	"os"
 	"os/exec"
 	"strconv"
 	"sync"
 	"time"
-	"unicode"
-	"unicode/utf8"
 	"unsafe"

 	"gioui.org/ui/f32"
@@ -41,13 +38,11 @@ import (
 //go:generate sed -i "1s;^;// +build linux,!android\\n\\n;" wayland_text_input.c

 /*
-#cgo LDFLAGS: -lwayland-client -lwayland-cursor -lxkbcommon
+#cgo LDFLAGS: -lwayland-client -lwayland-cursor

 #include <stdlib.h>
 #include <wayland-client.h>
 #include <wayland-cursor.h>
-#include <xkbcommon/xkbcommon.h>
-#include <xkbcommon/xkbcommon-compose.h>
 #include "wayland_text_input.h"
 #include "wayland_xdg_shell.h"
 #include "wayland_xdg_decoration.h"
@@ -56,27 +51,22 @@ import (
 import "C"

 type wlConn struct {
-	disp         *C.struct_wl_display
-	compositor   *C.struct_wl_compositor
-	wm           *C.struct_xdg_wm_base
-	imm          *C.struct_zwp_text_input_manager_v3
-	im           *C.struct_zwp_text_input_v3
-	shm          *C.struct_wl_shm
-	cursorTheme  *C.struct_wl_cursor_theme
-	cursor       *C.struct_wl_cursor
-	cursorSurf   *C.struct_wl_surface
-	decor        *C.struct_zxdg_decoration_manager_v1
-	seat         *C.struct_wl_seat
-	seatName     C.uint32_t
-	pointer      *C.struct_wl_pointer
-	touch        *C.struct_wl_touch
-	keyboard     *C.struct_wl_keyboard
-	xkb          *C.struct_xkb_context
-	xkbMap       *C.struct_xkb_keymap
-	xkbState     *C.struct_xkb_state
-	xkbCompTable *C.struct_xkb_compose_table
-	xkbCompState *C.struct_xkb_compose_state
-	utf8Buf      []byte
+	disp        *C.struct_wl_display
+	compositor  *C.struct_wl_compositor
+	wm          *C.struct_xdg_wm_base
+	imm         *C.struct_zwp_text_input_manager_v3
+	im          *C.struct_zwp_text_input_v3
+	shm         *C.struct_wl_shm
+	cursorTheme *C.struct_wl_cursor_theme
+	cursor      *C.struct_wl_cursor
+	cursorSurf  *C.struct_wl_surface
+	decor       *C.struct_zxdg_decoration_manager_v1
+	seat        *C.struct_wl_seat
+	seatName    C.uint32_t
+	pointer     *C.struct_wl_pointer
+	touch       *C.struct_wl_touch
+	keyboard    *C.struct_wl_keyboard
+	xkb         *xkb

 	repeat repeatState
 }
@@ -86,7 +76,7 @@ type repeatState struct {
 	delay time.Duration

 	key   C.uint32_t
-	win   *window
+	win   *Window
 	stopC chan struct{}

 	start time.Duration
@@ -121,6 +111,7 @@ type window struct {

 	stage             Stage
 	dead              bool
+	pendingErr        error
 	lastFrameCallback *C.struct_wl_callback

 	mu        sync.Mutex
@@ -154,11 +145,6 @@ var (
 	outputConfig = make(map[*C.struct_wl_output]*wlOutput)
 )

-var (
-	_XKB_MOD_NAME_CTRL  = []byte("Control\x00")
-	_XKB_MOD_NAME_SHIFT = []byte("Shift\x00")
-)
-
 func main() {
 	<-mainDone
 }
@@ -631,61 +617,20 @@ func (w *window) resetFling() {

 //export gio_onKeyboardKeymap
 func gio_onKeyboardKeymap(data unsafe.Pointer, keyboard *C.struct_wl_keyboard, format C.uint32_t, fd C.int32_t, size C.uint32_t) {
-	conn.repeat.Stop(0)
 	defer syscall.Close(int(fd))
-	if conn.xkbCompState != nil {
-		C.xkb_compose_state_unref(conn.xkbCompState)
-		conn.xkbCompState = nil
-	}
-	if conn.xkbCompTable != nil {
-		C.xkb_compose_table_unref(conn.xkbCompTable)
-		conn.xkbCompTable = nil
-	}
-	if conn.xkbState != nil {
-		C.xkb_state_unref(conn.xkbState)
-		conn.xkbState = nil
-	}
-	if conn.xkbMap != nil {
-		C.xkb_keymap_unref(conn.xkbMap)
-		conn.xkbMap = nil
+	conn.repeat.Stop(0)
+	if conn.xkb != nil {
+		conn.xkb.Destroy()
 	}
 	if format != C.WL_KEYBOARD_KEYMAP_FORMAT_XKB_V1 {
 		return
 	}
-	if conn.xkb == nil {
-		conn.xkb = C.xkb_context_new(C.XKB_CONTEXT_NO_FLAGS)
-	}
-	if conn.xkb == nil {
-		return
-	}
-	if conn.xkbCompTable == nil {
-		locale := os.Getenv("LC_ALL")
-		if locale == "" {
-			locale = os.Getenv("LC_CTYPE")
-		}
-		if locale == "" {
-			locale = os.Getenv("LANG")
-		}
-		if locale == "" {
-			locale = "C"
-		}
-		cloc := C.CString(locale)
-		defer C.free(unsafe.Pointer(cloc))
-		conn.xkbCompTable = C.xkb_compose_table_new_from_locale(conn.xkb, cloc, C.XKB_COMPOSE_COMPILE_NO_FLAGS)
-		if conn.xkbCompTable != nil {
-			conn.xkbCompState = C.xkb_compose_state_new(conn.xkbCompTable, C.XKB_COMPOSE_STATE_NO_FLAGS)
-		}
-	}
-	mapData, err := syscall.Mmap(int(fd), 0, int(size), syscall.PROT_READ, syscall.MAP_SHARED)
+	xkb, err := newXKB(format, fd, size)
 	if err != nil {
-		return
+		// TODO: Do better.
+		panic(err)
 	}
-	defer syscall.Munmap(mapData)
-	conn.xkbMap = C.xkb_keymap_new_from_buffer(conn.xkb, (*C.char)(unsafe.Pointer(&mapData[0])), C.size_t(size-1), C.XKB_KEYMAP_FORMAT_TEXT_V1, C.XKB_KEYMAP_COMPILE_NO_FLAGS)
-	if conn.xkbMap == nil {
-		return
-	}
-	conn.xkbState = C.xkb_state_new(conn.xkbMap)
+	conn.xkb = xkb
 }

 //export gio_onKeyboardEnter
@@ -706,16 +651,14 @@ func gio_onKeyboardLeave(data unsafe.Pointer, keyboard *C.struct_wl_keyboard, se
 //export gio_onKeyboardKey
 func gio_onKeyboardKey(data unsafe.Pointer, keyboard *C.struct_wl_keyboard, serial, timestamp, keyCode, state C.uint32_t) {
 	t := time.Duration(timestamp) * time.Millisecond
-	conn.repeat.Stop(t)
 	w := winMap[keyboard]
 	w.resetFling()
-	if state != C.WL_KEYBOARD_KEY_STATE_PRESSED || conn.xkbMap == nil || conn.xkbState == nil || conn.xkbCompState == nil {
+	conn.repeat.Stop(t)
+	if state != C.WL_KEYBOARD_KEY_STATE_PRESSED || conn.xkb == nil {
 		return
 	}
-	// According to the xkb_v1 spec: "to determine the xkb keycode, clients must add 8 to the key event keycode."
-	keyCode += 8
-	w.dispatchKey(keyCode)
-	if C.xkb_keymap_key_repeats(conn.xkbMap, C.xkb_keycode_t(keyCode)) == 1 {
+	conn.xkb.dispatchKey(w.w, keyCode)
+	if conn.xkb.isRepeatKey(keyCode) {
 		conn.repeat.Start(w, keyCode, t)
 	}
 }
@@ -730,7 +673,7 @@ func (r *repeatState) Start(w *window, keyCode C.uint32_t, t time.Duration) {
 	r.now = 0
 	r.stopC = stopC
 	r.key = keyCode
-	r.win = w
+	r.win = w.w
 	rate, delay := r.rate, r.delay
 	go func() {
 		timer := time.NewTimer(delay)
@@ -785,7 +728,7 @@ func (r *repeatState) Repeat() {
 		if r.last+delay > now {
 			break
 		}
-		r.win.dispatchKey(r.key)
+		conn.xkb.dispatchKey(r.win, r.key)
 		r.last += delay
 	}
 }
@@ -818,7 +761,7 @@ loop:
 			break
 		}
 		if w.dead {
-			w.w.event(DestroyEvent{})
+			w.w.event(DestroyEvent{Err: w.pendingErr})
 			break
 		}
 		// Clear poll events.
@@ -898,65 +841,13 @@ func (w *window) destroy() {
 	}
 }

-func (w *window) dispatchKey(keyCode C.uint32_t) {
-	if len(conn.utf8Buf) == 0 {
-		conn.utf8Buf = make([]byte, 1)
-	}
-	sym := C.xkb_state_key_get_one_sym(conn.xkbState, C.xkb_keycode_t(keyCode))
-	if n, ok := convertKeysym(sym); ok {
-		cmd := key.Event{Name: n}
-		if C.xkb_state_mod_name_is_active(conn.xkbState, (*C.char)(unsafe.Pointer(&_XKB_MOD_NAME_CTRL[0])), C.XKB_STATE_MODS_EFFECTIVE) == 1 {
-			cmd.Modifiers |= key.ModCommand
-		}
-		if C.xkb_state_mod_name_is_active(conn.xkbState, (*C.char)(unsafe.Pointer(&_XKB_MOD_NAME_SHIFT[0])), C.XKB_STATE_MODS_EFFECTIVE) == 1 {
-			cmd.Modifiers |= key.ModShift
-		}
-		w.w.event(cmd)
-	}
-	C.xkb_compose_state_feed(conn.xkbCompState, sym)
-	var size C.int
-	switch C.xkb_compose_state_get_status(conn.xkbCompState) {
-	case C.XKB_COMPOSE_CANCELLED, C.XKB_COMPOSE_COMPOSING:
-		return
-	case C.XKB_COMPOSE_COMPOSED:
-		size = C.xkb_compose_state_get_utf8(conn.xkbCompState, (*C.char)(unsafe.Pointer(&conn.utf8Buf[0])), C.size_t(len(conn.utf8Buf)))
-		if int(size) >= len(conn.utf8Buf) {
-			conn.utf8Buf = make([]byte, size+1)
-			size = C.xkb_compose_state_get_utf8(conn.xkbCompState, (*C.char)(unsafe.Pointer(&conn.utf8Buf[0])), C.size_t(len(conn.utf8Buf)))
-		}
-		C.xkb_compose_state_reset(conn.xkbCompState)
-	case C.XKB_COMPOSE_NOTHING:
-		size = C.xkb_state_key_get_utf8(conn.xkbState, C.xkb_keycode_t(keyCode), (*C.char)(unsafe.Pointer(&conn.utf8Buf[0])), C.size_t(len(conn.utf8Buf)))
-		if int(size) >= len(conn.utf8Buf) {
-			conn.utf8Buf = make([]byte, size+1)
-			size = C.xkb_state_key_get_utf8(conn.xkbState, C.xkb_keycode_t(keyCode), (*C.char)(unsafe.Pointer(&conn.utf8Buf[0])), C.size_t(len(conn.utf8Buf)))
-		}
-	}
-	// Report only printable runes.
-	str := conn.utf8Buf[:size]
-	var n int
-	for n < len(str) {
-		r, s := utf8.DecodeRune(str)
-		if unicode.IsPrint(r) {
-			n += s
-		} else {
-			copy(str[n:], str[n+s:])
-			str = str[:len(str)-s]
-		}
-	}
-	if len(str) > 0 {
-		w.w.event(key.EditEvent{Text: string(str)})
-	}
-}
-
 //export gio_onKeyboardModifiers
 func gio_onKeyboardModifiers(data unsafe.Pointer, keyboard *C.struct_wl_keyboard, serial, depressed, latched, locked, group C.uint32_t) {
 	conn.repeat.Stop(0)
-	if conn.xkbState == nil {
+	if conn.xkb == nil {
 		return
 	}
-	xkbGrp := C.xkb_layout_index_t(group)
-	C.xkb_state_update_mask(conn.xkbState, C.xkb_mod_mask_t(depressed), C.xkb_mod_mask_t(latched), C.xkb_mod_mask_t(locked), xkbGrp, xkbGrp, xkbGrp)
+	conn.xkb.updateMask(depressed, latched, locked, group)
 }

 //export gio_onKeyboardRepeatInfo
@@ -1096,6 +987,13 @@ func (w *window) isAnimating() bool {
 	return w.animating || w.flinger.Active()
 }

+func (w *window) kill(err error) {
+	if w.pendingErr == nil {
+		w.pendingErr = err
+	}
+	w.dead = true
+}
+
 func (w *window) draw(sync bool) {
 	w.flushScroll()
 	w.mu.Lock()
@@ -1228,22 +1126,9 @@ func waylandConnect() error {

 func (c *wlConn) destroy() {
 	c.repeat.Stop(0)
-	if c.xkbCompState != nil {
-		C.xkb_compose_state_unref(c.xkbCompState)
-		c.xkbCompState = nil
-	}
-	if c.xkbCompTable != nil {
-		C.xkb_compose_table_unref(c.xkbCompTable)
-		c.xkbCompTable = nil
-	}
-	if c.xkbState != nil {
-		C.xkb_state_unref(conn.xkbState)
-	}
-	if c.xkbMap != nil {
-		C.xkb_keymap_unref(c.xkbMap)
-	}
 	if c.xkb != nil {
-		C.xkb_context_unref(c.xkb)
+		c.xkb.Destroy()
+		c.xkb = nil
 	}
 	if c.cursorSurf != nil {
 		C.wl_surface_destroy(c.cursorSurf)
@@ -1297,44 +1182,3 @@ func fromFixed(v C.wl_fixed_t) float32 {
 	f := math.Float64frombits(b) - (3 << 43)
 	return float32(f)
 }
-
-func convertKeysym(s C.xkb_keysym_t) (rune, bool) {
-	if '0' <= s && s <= '9' || 'A' <= s && s <= 'Z' {
-		return rune(s), true
-	}
-	if 'a' <= s && s <= 'z' {
-		return rune(s - 0x20), true
-	}
-	var n rune
-	switch s {
-	case C.XKB_KEY_Escape:
-		n = key.NameEscape
-	case C.XKB_KEY_Left:
-		n = key.NameLeftArrow
-	case C.XKB_KEY_Right:
-		n = key.NameRightArrow
-	case C.XKB_KEY_Return:
-		n = key.NameReturn
-	case C.XKB_KEY_KP_Enter:
-		n = key.NameEnter
-	case C.XKB_KEY_Up:
-		n = key.NameUpArrow
-	case C.XKB_KEY_Down:
-		n = key.NameDownArrow
-	case C.XKB_KEY_Home:
-		n = key.NameHome
-	case C.XKB_KEY_End:
-		n = key.NameEnd
-	case C.XKB_KEY_BackSpace:
-		n = key.NameDeleteBackward
-	case C.XKB_KEY_Delete:
-		n = key.NameDeleteForward
-	case C.XKB_KEY_Page_Up:
-		n = key.NamePageUp
-	case C.XKB_KEY_Page_Down:
-		n = key.NamePageDown
-	default:
-		return 0, false
-	}
-	return n, true
-}
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+// +build !android
+
+package app
+
+/*
+#cgo LDFLAGS: -lxkbcommon
+
+#include <stdlib.h>
+#include <xkbcommon/xkbcommon.h>
+#include <xkbcommon/xkbcommon-compose.h>
+*/
+import "C"
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"syscall"
+	"unicode"
+	"unicode/utf8"
+	"unsafe"
+
+	"gioui.org/ui/key"
+)
+
+type xkb struct {
+	ctx       *C.struct_xkb_context
+	keyMap    *C.struct_xkb_keymap
+	state     *C.struct_xkb_state
+	compTable *C.struct_xkb_compose_table
+	compState *C.struct_xkb_compose_state
+	utf8Buf   []byte
+}
+
+var (
+	_XKB_MOD_NAME_CTRL  = []byte("Control\x00")
+	_XKB_MOD_NAME_SHIFT = []byte("Shift\x00")
+)
+
+func (x *xkb) Destroy() {
+	if x.state != nil {
+		C.xkb_compose_state_unref(x.compState)
+		x.compState = nil
+	}
+	if x.compTable != nil {
+		C.xkb_compose_table_unref(x.compTable)
+		x.compTable = nil
+	}
+	if x.state != nil {
+		C.xkb_state_unref(x.state)
+		x.state = nil
+	}
+	if x.keyMap != nil {
+		C.xkb_keymap_unref(x.keyMap)
+		x.keyMap = nil
+	}
+	if x.ctx != nil {
+		C.xkb_context_unref(x.ctx)
+		x.ctx = nil
+	}
+}
+
+func newXKB(format C.uint32_t, fd C.int32_t, size C.uint32_t) (*xkb, error) {
+	xkb := &xkb{
+		ctx: C.xkb_context_new(C.XKB_CONTEXT_NO_FLAGS),
+	}
+	if xkb.ctx == nil {
+		return nil, errors.New("newXKB: xkb_context_new failed")
+	}
+	locale := os.Getenv("LC_ALL")
+	if locale == "" {
+		locale = os.Getenv("LC_CTYPE")
+	}
+	if locale == "" {
+		locale = os.Getenv("LANG")
+	}
+	if locale == "" {
+		locale = "C"
+	}
+	cloc := C.CString(locale)
+	defer C.free(unsafe.Pointer(cloc))
+	xkb.compTable = C.xkb_compose_table_new_from_locale(xkb.ctx, cloc, C.XKB_COMPOSE_COMPILE_NO_FLAGS)
+	if xkb.compTable == nil {
+		xkb.Destroy()
+		return nil, errors.New("newXKB: xkb_compose_table_new_from_locale failed")
+	}
+	xkb.compState = C.xkb_compose_state_new(xkb.compTable, C.XKB_COMPOSE_STATE_NO_FLAGS)
+	if xkb.compState == nil {
+		xkb.Destroy()
+		return nil, errors.New("newXKB: xkb_compose_state_new failed")
+	}
+	mapData, err := syscall.Mmap(int(fd), 0, int(size), syscall.PROT_READ, syscall.MAP_SHARED)
+	if err != nil {
+		xkb.Destroy()
+		return nil, fmt.Errorf("newXKB: mmap of keymap failed: %v", err)
+	}
+	defer syscall.Munmap(mapData)
+	xkb.keyMap = C.xkb_keymap_new_from_buffer(xkb.ctx, (*C.char)(unsafe.Pointer(&mapData[0])), C.size_t(size-1), C.XKB_KEYMAP_FORMAT_TEXT_V1, C.XKB_KEYMAP_COMPILE_NO_FLAGS)
+	if xkb.keyMap == nil {
+		xkb.Destroy()
+		return nil, errors.New("newXKB: xkb_keymap_new_from_buffer failed")
+	}
+	xkb.state = C.xkb_state_new(xkb.keyMap)
+	if xkb.state == nil {
+		xkb.Destroy()
+		return nil, errors.New("newXKB: xkb_state_new failed")
+	}
+	return xkb, nil
+}
+
+func (x *xkb) dispatchKey(w *Window, keyCode C.uint32_t) {
+	keyCode = mapXKBKeyCode(keyCode)
+	if len(x.utf8Buf) == 0 {
+		x.utf8Buf = make([]byte, 1)
+	}
+	sym := C.xkb_state_key_get_one_sym(x.state, C.xkb_keycode_t(keyCode))
+	if n, ok := convertKeysym(sym); ok {
+		cmd := key.Event{Name: n}
+		if C.xkb_state_mod_name_is_active(x.state, (*C.char)(unsafe.Pointer(&_XKB_MOD_NAME_CTRL[0])), C.XKB_STATE_MODS_EFFECTIVE) == 1 {
+			cmd.Modifiers |= key.ModCommand
+		}
+		if C.xkb_state_mod_name_is_active(x.state, (*C.char)(unsafe.Pointer(&_XKB_MOD_NAME_SHIFT[0])), C.XKB_STATE_MODS_EFFECTIVE) == 1 {
+			cmd.Modifiers |= key.ModShift
+		}
+		w.event(cmd)
+	}
+	C.xkb_compose_state_feed(x.compState, sym)
+	var size C.int
+	switch C.xkb_compose_state_get_status(x.compState) {
+	case C.XKB_COMPOSE_CANCELLED, C.XKB_COMPOSE_COMPOSING:
+		return
+	case C.XKB_COMPOSE_COMPOSED:
+		size = C.xkb_compose_state_get_utf8(x.compState, (*C.char)(unsafe.Pointer(&x.utf8Buf[0])), C.size_t(len(x.utf8Buf)))
+		if int(size) >= len(x.utf8Buf) {
+			x.utf8Buf = make([]byte, size+1)
+			size = C.xkb_compose_state_get_utf8(x.compState, (*C.char)(unsafe.Pointer(&x.utf8Buf[0])), C.size_t(len(x.utf8Buf)))
+		}
+		C.xkb_compose_state_reset(x.compState)
+	case C.XKB_COMPOSE_NOTHING:
+		size = C.xkb_state_key_get_utf8(x.state, C.xkb_keycode_t(keyCode), (*C.char)(unsafe.Pointer(&x.utf8Buf[0])), C.size_t(len(x.utf8Buf)))
+		if int(size) >= len(x.utf8Buf) {
+			x.utf8Buf = make([]byte, size+1)
+			size = C.xkb_state_key_get_utf8(x.state, C.xkb_keycode_t(keyCode), (*C.char)(unsafe.Pointer(&x.utf8Buf[0])), C.size_t(len(x.utf8Buf)))
+		}
+	}
+	// Report only printable runes.
+	str := x.utf8Buf[:size]
+	var n int
+	for n < len(str) {
+		r, s := utf8.DecodeRune(str)
+		if unicode.IsPrint(r) {
+			n += s
+		} else {
+			copy(str[n:], str[n+s:])
+			str = str[:len(str)-s]
+		}
+	}
+	if len(str) > 0 {
+		w.event(key.EditEvent{Text: string(str)})
+	}
+}
+
+func (x *xkb) isRepeatKey(keyCode C.uint32_t) bool {
+	keyCode = mapXKBKeyCode(keyCode)
+	return C.xkb_keymap_key_repeats(conn.xkb.keyMap, C.xkb_keycode_t(keyCode)) == 1
+}
+
+func (x *xkb) updateMask(depressed, latched, locked, group C.uint32_t) {
+	xkbGrp := C.xkb_layout_index_t(group)
+	C.xkb_state_update_mask(conn.xkb.state, C.xkb_mod_mask_t(depressed), C.xkb_mod_mask_t(latched), C.xkb_mod_mask_t(locked), xkbGrp, xkbGrp, xkbGrp)
+}
+
+func mapXKBKeyCode(keyCode C.uint32_t) C.uint32_t {
+	// According to the xkb_v1 spec: "to determine the xkb keycode, clients must add 8 to the key event keycode."
+	return keyCode + 8
+}
+
+func convertKeysym(s C.xkb_keysym_t) (rune, bool) {
+	if '0' <= s && s <= '9' || 'A' <= s && s <= 'Z' {
+		return rune(s), true
+	}
+	if 'a' <= s && s <= 'z' {
+		return rune(s - 0x20), true
+	}
+	var n rune
+	switch s {
+	case C.XKB_KEY_Escape:
+		n = key.NameEscape
+	case C.XKB_KEY_Left:
+		n = key.NameLeftArrow
+	case C.XKB_KEY_Right:
+		n = key.NameRightArrow
+	case C.XKB_KEY_Return:
+		n = key.NameReturn
+	case C.XKB_KEY_KP_Enter:
+		n = key.NameEnter
+	case C.XKB_KEY_Up:
+		n = key.NameUpArrow
+	case C.XKB_KEY_Down:
+		n = key.NameDownArrow
+	case C.XKB_KEY_Home:
+		n = key.NameHome
+	case C.XKB_KEY_End:
+		n = key.NameEnd
+	case C.XKB_KEY_BackSpace:
+		n = key.NameDeleteBackward
+	case C.XKB_KEY_Delete:
+		n = key.NameDeleteForward
+	case C.XKB_KEY_Page_Up:
+		n = key.NamePageUp
+	case C.XKB_KEY_Page_Down:
+		n = key.NamePageDown
+	default:
+		return 0, false
+	}
+	return n, true
+}