Merge pull request #39457 from bruvzg/kbd_layouts

Add keyboard layout enumeration / set / get functions.

6 files changed, 290 insertions, 136 deletions

diff --git a/platform/linuxbsd/display_server_x11.cpp b/platform/linuxbsd/display_server_x11.cpp
index ef5ac66b34..a0954600a2 100644
--- a/platform/linuxbsd/display_server_x11.cpp
+++ b/platform/linuxbsd/display_server_x11.cpp
@@ -1846,37 +1846,106 @@ void DisplayServerX11::cursor_set_custom_image(const RES &p_cursor, CursorShape
 	}
 }
 
-DisplayServerX11::LatinKeyboardVariant DisplayServerX11::get_latin_keyboard_variant() const {
-	_THREAD_SAFE_METHOD_
-
-	XkbDescRec *xkbdesc = XkbAllocKeyboard();
-	ERR_FAIL_COND_V(!xkbdesc, LATIN_KEYBOARD_QWERTY);
+int DisplayServerX11::keyboard_get_layout_count() const {
+	int _group_count = 0;
+	XkbDescRec *kbd = XkbAllocKeyboard();
+	if (kbd) {
+		kbd->dpy = x11_display;
+		XkbGetControls(x11_display, XkbAllControlsMask, kbd);
+		XkbGetNames(x11_display, XkbSymbolsNameMask, kbd);
+
+		const Atom *groups = kbd->names->groups;
+		if (kbd->ctrls != NULL) {
+			_group_count = kbd->ctrls->num_groups;
+		} else {
+			while (_group_count < XkbNumKbdGroups && groups[_group_count] != None) {
+				_group_count++;
+			}
+		}
+		XkbFreeKeyboard(kbd, 0, true);
+	}
+	return _group_count;
+}
 
-	XkbGetNames(x11_display, XkbSymbolsNameMask, xkbdesc);
-	ERR_FAIL_COND_V(!xkbdesc->names, LATIN_KEYBOARD_QWERTY);
-	ERR_FAIL_COND_V(!xkbdesc->names->symbols, LATIN_KEYBOARD_QWERTY);
+int DisplayServerX11::keyboard_get_current_layout() const {
+	XkbStateRec state;
+	XkbGetState(x11_display, XkbUseCoreKbd, &state);
+	return state.group;
+}
 
-	char *layout = XGetAtomName(x11_display, xkbdesc->names->symbols);
-	ERR_FAIL_COND_V(!layout, LATIN_KEYBOARD_QWERTY);
+void DisplayServerX11::keyboard_set_current_layout(int p_index) {
+	ERR_FAIL_INDEX(p_index, keyboard_get_layout_count());
+	XkbLockGroup(x11_display, XkbUseCoreKbd, p_index);
+}
 
-	Vector<String> info = String(layout).split("+");
-	ERR_FAIL_INDEX_V(1, info.size(), LATIN_KEYBOARD_QWERTY);
+String DisplayServerX11::keyboard_get_layout_language(int p_index) const {
+	String ret;
+	XkbDescRec *kbd = XkbAllocKeyboard();
+	if (kbd) {
+		kbd->dpy = x11_display;
+		XkbGetControls(x11_display, XkbAllControlsMask, kbd);
+		XkbGetNames(x11_display, XkbSymbolsNameMask, kbd);
+		XkbGetNames(x11_display, XkbGroupNamesMask, kbd);
+
+		int _group_count = 0;
+		const Atom *groups = kbd->names->groups;
+		if (kbd->ctrls != NULL) {
+			_group_count = kbd->ctrls->num_groups;
+		} else {
+			while (_group_count < XkbNumKbdGroups && groups[_group_count] != None) {
+				_group_count++;
+			}
+		}
 
-	if (info[1].find("colemak") != -1) {
-		return LATIN_KEYBOARD_COLEMAK;
-	} else if (info[1].find("qwertz") != -1) {
-		return LATIN_KEYBOARD_QWERTZ;
-	} else if (info[1].find("azerty") != -1) {
-		return LATIN_KEYBOARD_AZERTY;
-	} else if (info[1].find("qzerty") != -1) {
-		return LATIN_KEYBOARD_QZERTY;
-	} else if (info[1].find("dvorak") != -1) {
-		return LATIN_KEYBOARD_DVORAK;
-	} else if (info[1].find("neo") != -1) {
-		return LATIN_KEYBOARD_NEO;
+		Atom names = kbd->names->symbols;
+		if (names != None) {
+			char *name = XGetAtomName(x11_display, names);
+			Vector<String> info = String(name).split("+");
+			if (p_index >= 0 && p_index < _group_count) {
+				if (p_index + 1 < info.size()) {
+					ret = info[p_index + 1]; // Skip "pc" at the start and "inet"/"group" at the end of symbols.
+				} else {
+					ret = "en"; // No symbol for layout fallback to "en".
+				}
+			} else {
+				ERR_PRINT("Index " + itos(p_index) + "is out of bounds (" + itos(_group_count) + ").");
+			}
+			XFree(name);
+		}
+		XkbFreeKeyboard(kbd, 0, true);
 	}
+	return ret.substr(0, 2);
+}
+
+String DisplayServerX11::keyboard_get_layout_name(int p_index) const {
+	String ret;
+	XkbDescRec *kbd = XkbAllocKeyboard();
+	if (kbd) {
+		kbd->dpy = x11_display;
+		XkbGetControls(x11_display, XkbAllControlsMask, kbd);
+		XkbGetNames(x11_display, XkbSymbolsNameMask, kbd);
+		XkbGetNames(x11_display, XkbGroupNamesMask, kbd);
+
+		int _group_count = 0;
+		const Atom *groups = kbd->names->groups;
+		if (kbd->ctrls != NULL) {
+			_group_count = kbd->ctrls->num_groups;
+		} else {
+			while (_group_count < XkbNumKbdGroups && groups[_group_count] != None) {
+				_group_count++;
+			}
+		}
 
-	return LATIN_KEYBOARD_QWERTY;
+		if (p_index >= 0 && p_index < _group_count) {
+			char *full_name = XGetAtomName(x11_display, groups[p_index]);
+			ret.parse_utf8(full_name);
+			XFree(full_name);
+		} else {
+			ERR_PRINT("Index " + itos(p_index) + "is out of bounds (" + itos(_group_count) + ").");
+		}
+		XkbFreeKeyboard(kbd, 0, true);
+	}
+	return ret;
 }
 
 DisplayServerX11::Property DisplayServerX11::_read_property(Display *p_display, Window p_window, Atom p_property) {
diff --git a/platform/linuxbsd/display_server_x11.h b/platform/linuxbsd/display_server_x11.h
index b5ea71f72a..f01b9a2323 100644
--- a/platform/linuxbsd/display_server_x11.h
+++ b/platform/linuxbsd/display_server_x11.h
@@ -327,7 +327,11 @@ public:
 	virtual CursorShape cursor_get_shape() const;
 	virtual void cursor_set_custom_image(const RES &p_cursor, CursorShape p_shape, const Vector2 &p_hotspot);
 
-	virtual LatinKeyboardVariant get_latin_keyboard_variant() const;
+	virtual int keyboard_get_layout_count() const;
+	virtual int keyboard_get_current_layout() const;
+	virtual void keyboard_set_current_layout(int p_index);
+	virtual String keyboard_get_layout_language(int p_index) const;
+	virtual String keyboard_get_layout_name(int p_index) const;
 
 	virtual void process_events();
 
diff --git a/platform/osx/display_server_osx.h b/platform/osx/display_server_osx.h
index 8133dfe2c4..fddb1d0ca6 100644
--- a/platform/osx/display_server_osx.h
+++ b/platform/osx/display_server_osx.h
@@ -281,7 +281,11 @@ public:
 
 	virtual bool get_swap_ok_cancel();
 
-	virtual LatinKeyboardVariant get_latin_keyboard_variant() const;
+	virtual int keyboard_get_layout_count() const;
+	virtual int keyboard_get_current_layout() const;
+	virtual void keyboard_set_current_layout(int p_index);
+	virtual String keyboard_get_layout_language(int p_index) const;
+	virtual String keyboard_get_layout_name(int p_index) const;
 
 	virtual void process_events();
 	virtual void force_process_and_drop_events();
diff --git a/platform/osx/display_server_osx.mm b/platform/osx/display_server_osx.mm
index 9a1191490c..4a94e09c1c 100644
--- a/platform/osx/display_server_osx.mm
+++ b/platform/osx/display_server_osx.mm
@@ -2987,85 +2987,129 @@ void DisplayServerOSX::cursor_set_custom_image(const RES &p_cursor, CursorShape
 	}
 }
 
+struct LayoutInfo {
+	String name;
+	String code;
+};
+
+static Vector<LayoutInfo> kbd_layouts;
+static int current_layout = 0;
 static bool keyboard_layout_dirty = true;
 static void keyboard_layout_changed(CFNotificationCenterRef center, void *observer, CFStringRef name, const void *object, CFDictionaryRef user_info) {
+	kbd_layouts.clear();
+	current_layout = 0;
 	keyboard_layout_dirty = true;
 }
 
-// Returns string representation of keys, if they are printable.
-static NSString *createStringForKeys(const CGKeyCode *keyCode, int length) {
-	TISInputSourceRef currentKeyboard = TISCopyCurrentKeyboardInputSource();
-	if (!currentKeyboard)
-		return nil;
+void _update_keyboard_layouts() {
+	@autoreleasepool {
+		TISInputSourceRef cur_source = TISCopyCurrentKeyboardInputSource();
+		NSString *cur_name = (NSString *)TISGetInputSourceProperty(cur_source, kTISPropertyLocalizedName);
+		CFRelease(cur_source);
 
-	CFDataRef layoutData = (CFDataRef)TISGetInputSourceProperty(currentKeyboard, kTISPropertyUnicodeKeyLayoutData);
-	if (!layoutData)
-		return nil;
+		// Enum IME layouts
+		NSDictionary *filter_ime = @{ (NSString *)kTISPropertyInputSourceType : (NSString *)kTISTypeKeyboardInputMode };
+		NSArray *list_ime = (NSArray *)TISCreateInputSourceList((CFDictionaryRef)filter_ime, false);
+		for (NSUInteger i = 0; i < [list_ime count]; i++) {
+			LayoutInfo ly;
+			NSString *name = (NSString *)TISGetInputSourceProperty((TISInputSourceRef)[list_ime objectAtIndex:i], kTISPropertyLocalizedName);
+			ly.name.parse_utf8([name UTF8String]);
 
-	const UCKeyboardLayout *keyboardLayout = (const UCKeyboardLayout *)CFDataGetBytePtr(layoutData);
+			NSArray *langs = (NSArray *)TISGetInputSourceProperty((TISInputSourceRef)[list_ime objectAtIndex:i], kTISPropertyInputSourceLanguages);
+			ly.code.parse_utf8([(NSString *)[langs objectAtIndex:0] UTF8String]);
+			kbd_layouts.push_back(ly);
 
-	OSStatus err;
-	CFMutableStringRef output = CFStringCreateMutable(NULL, 0);
+			if ([name isEqualToString:cur_name]) {
+				current_layout = kbd_layouts.size() - 1;
+			}
+		}
+		[list_ime release];
 
-	for (int i = 0; i < length; ++i) {
-		UInt32 keysDown = 0;
-		UniChar chars[4];
-		UniCharCount realLength;
+		// Enum plain keyboard layouts
+		NSDictionary *filter_kbd = @{ (NSString *)kTISPropertyInputSourceType : (NSString *)kTISTypeKeyboardLayout };
+		NSArray *list_kbd = (NSArray *)TISCreateInputSourceList((CFDictionaryRef)filter_kbd, false);
+		for (NSUInteger i = 0; i < [list_kbd count]; i++) {
+			LayoutInfo ly;
+			NSString *name = (NSString *)TISGetInputSourceProperty((TISInputSourceRef)[list_kbd objectAtIndex:i], kTISPropertyLocalizedName);
+			ly.name.parse_utf8([name UTF8String]);
 
-		err = UCKeyTranslate(keyboardLayout,
-				keyCode[i],
-				kUCKeyActionDisplay,
-				0,
-				LMGetKbdType(),
-				kUCKeyTranslateNoDeadKeysBit,
-				&keysDown,
-				sizeof(chars) / sizeof(chars[0]),
-				&realLength,
-				chars);
+			NSArray *langs = (NSArray *)TISGetInputSourceProperty((TISInputSourceRef)[list_kbd objectAtIndex:i], kTISPropertyInputSourceLanguages);
+			ly.code.parse_utf8([(NSString *)[langs objectAtIndex:0] UTF8String]);
+			kbd_layouts.push_back(ly);
 
-		if (err != noErr) {
-			CFRelease(output);
-			return nil;
+			if ([name isEqualToString:cur_name]) {
+				current_layout = kbd_layouts.size() - 1;
+			}
 		}
-
-		CFStringAppendCharacters(output, chars, 1);
+		[list_kbd release];
 	}
 
-	return (NSString *)output;
+	keyboard_layout_dirty = false;
 }
 
-DisplayServerOSX::LatinKeyboardVariant DisplayServerOSX::get_latin_keyboard_variant() const {
-	_THREAD_SAFE_METHOD_
-
-	static LatinKeyboardVariant layout = LATIN_KEYBOARD_QWERTY;
+int DisplayServerOSX::keyboard_get_layout_count() const {
+	if (keyboard_layout_dirty) {
+		_update_keyboard_layouts();
+	}
+	return kbd_layouts.size();
+}
 
+void DisplayServerOSX::keyboard_set_current_layout(int p_index) {
 	if (keyboard_layout_dirty) {
-		layout = LATIN_KEYBOARD_QWERTY;
+		_update_keyboard_layouts();
+	}
+
+	ERR_FAIL_INDEX(p_index, kbd_layouts.size());
 
-		CGKeyCode keys[] = { kVK_ANSI_Q, kVK_ANSI_W, kVK_ANSI_E, kVK_ANSI_R, kVK_ANSI_T, kVK_ANSI_Y };
-		NSString *test = createStringForKeys(keys, 6);
+	NSString *cur_name = [NSString stringWithUTF8String:kbd_layouts[p_index].name.utf8().get_data()];
 
-		if ([test isEqualToString:@"qwertz"]) {
-			layout = LATIN_KEYBOARD_QWERTZ;
-		} else if ([test isEqualToString:@"azerty"]) {
-			layout = LATIN_KEYBOARD_AZERTY;
-		} else if ([test isEqualToString:@"qzerty"]) {
-			layout = LATIN_KEYBOARD_QZERTY;
-		} else if ([test isEqualToString:@"',.pyf"]) {
-			layout = LATIN_KEYBOARD_DVORAK;
-		} else if ([test isEqualToString:@"xvlcwk"]) {
-			layout = LATIN_KEYBOARD_NEO;
-		} else if ([test isEqualToString:@"qwfpgj"]) {
-			layout = LATIN_KEYBOARD_COLEMAK;
+	NSDictionary *filter_kbd = @{ (NSString *)kTISPropertyInputSourceType : (NSString *)kTISTypeKeyboardLayout };
+	NSArray *list_kbd = (NSArray *)TISCreateInputSourceList((CFDictionaryRef)filter_kbd, false);
+	for (NSUInteger i = 0; i < [list_kbd count]; i++) {
+		NSString *name = (NSString *)TISGetInputSourceProperty((TISInputSourceRef)[list_kbd objectAtIndex:i], kTISPropertyLocalizedName);
+		if ([name isEqualToString:cur_name]) {
+			TISSelectInputSource((TISInputSourceRef)[list_kbd objectAtIndex:i]);
+			break;
 		}
+	}
+	[list_kbd release];
 
-		[test release];
+	NSDictionary *filter_ime = @{ (NSString *)kTISPropertyInputSourceType : (NSString *)kTISTypeKeyboardInputMode };
+	NSArray *list_ime = (NSArray *)TISCreateInputSourceList((CFDictionaryRef)filter_ime, false);
+	for (NSUInteger i = 0; i < [list_ime count]; i++) {
+		NSString *name = (NSString *)TISGetInputSourceProperty((TISInputSourceRef)[list_ime objectAtIndex:i], kTISPropertyLocalizedName);
+		if ([name isEqualToString:cur_name]) {
+			TISSelectInputSource((TISInputSourceRef)[list_ime objectAtIndex:i]);
+			break;
+		}
+	}
+	[list_ime release];
+}
+
+int DisplayServerOSX::keyboard_get_current_layout() const {
+	if (keyboard_layout_dirty) {
+		_update_keyboard_layouts();
+	}
 
-		keyboard_layout_dirty = false;
-		return layout;
+	return current_layout;
+}
+
+String DisplayServerOSX::keyboard_get_layout_language(int p_index) const {
+	if (keyboard_layout_dirty) {
+		_update_keyboard_layouts();
+	}
+
+	ERR_FAIL_INDEX_V(p_index, kbd_layouts.size(), "");
+	return kbd_layouts[p_index].code;
+}
+
+String DisplayServerOSX::keyboard_get_layout_name(int p_index) const {
+	if (keyboard_layout_dirty) {
+		_update_keyboard_layouts();
 	}
 
-	return layout;
+	ERR_FAIL_INDEX_V(p_index, kbd_layouts.size(), "");
+	return kbd_layouts[p_index].name;
 }
 
 void DisplayServerOSX::_push_input(const Ref<InputEvent> &p_event) {
diff --git a/platform/windows/display_server_windows.cpp b/platform/windows/display_server_windows.cpp
index 9d8344fa7e..0b7130db74 100644
--- a/platform/windows/display_server_windows.cpp
+++ b/platform/windows/display_server_windows.cpp
@@ -1372,70 +1372,99 @@ void DisplayServerWindows::enable_for_stealing_focus(OS::ProcessID pid) {
 	AllowSetForegroundWindow(pid);
 }
 
-DisplayServer::LatinKeyboardVariant DisplayServerWindows::get_latin_keyboard_variant() const {
-	_THREAD_SAFE_METHOD_
+int DisplayServerWindows::keyboard_get_layout_count() const {
+	return GetKeyboardLayoutList(0, NULL);
+}
 
-	unsigned long azerty[] = {
-		0x00020401, // Arabic (102) AZERTY
-		0x0001080c, // Belgian (Comma)
-		0x0000080c, // Belgian French
-		0x0000040c, // French
-		0 // <--- STOP MARK
-	};
-	unsigned long qwertz[] = {
-		0x0000041a, // Croation
-		0x00000405, // Czech
-		0x00000407, // German
-		0x00010407, // German (IBM)
-		0x0000040e, // Hungarian
-		0x0000046e, // Luxembourgish
-		0x00010415, // Polish (214)
-		0x00000418, // Romanian (Legacy)
-		0x0000081a, // Serbian (Latin)
-		0x0000041b, // Slovak
-		0x00000424, // Slovenian
-		0x0001042e, // Sorbian Extended
-		0x0002042e, // Sorbian Standard
-		0x0000042e, // Sorbian Standard (Legacy)
-		0x0000100c, // Swiss French
-		0x00000807, // Swiss German
-		0 // <--- STOP MARK
-	};
-	unsigned long dvorak[] = {
-		0x00010409, // US-Dvorak
-		0x00030409, // US-Dvorak for left hand
-		0x00040409, // US-Dvorak for right hand
-		0 // <--- STOP MARK
-	};
+int DisplayServerWindows::keyboard_get_current_layout() const {
+	HKL cur_layout = GetKeyboardLayout(0);
+
+	int layout_count = GetKeyboardLayoutList(0, NULL);
+	HKL *layouts = (HKL *)memalloc(layout_count * sizeof(HKL));
+	GetKeyboardLayoutList(layout_count, layouts);
+
+	for (int i = 0; i < layout_count; i++) {
+		if (cur_layout == layouts[i]) {
+			memfree(layouts);
+			return i;
+		}
+	}
+	memfree(layouts);
+	return -1;
+}
+
+void DisplayServerWindows::keyboard_set_current_layout(int p_index) {
+	int layout_count = GetKeyboardLayoutList(0, NULL);
+
+	ERR_FAIL_INDEX(p_index, layout_count);
+
+	HKL *layouts = (HKL *)memalloc(layout_count * sizeof(HKL));
+	GetKeyboardLayoutList(layout_count, layouts);
+	ActivateKeyboardLayout(layouts[p_index], KLF_SETFORPROCESS);
+	memfree(layouts);
+}
+
+String DisplayServerWindows::keyboard_get_layout_language(int p_index) const {
+	int layout_count = GetKeyboardLayoutList(0, NULL);
 
-	char name[KL_NAMELENGTH + 1];
-	name[0] = 0;
-	GetKeyboardLayoutNameA(name);
+	ERR_FAIL_INDEX_V(p_index, layout_count, "");
 
-	unsigned long hex = strtoul(name, nullptr, 16);
+	HKL *layouts = (HKL *)memalloc(layout_count * sizeof(HKL));
+	GetKeyboardLayoutList(layout_count, layouts);
 
-	int i = 0;
-	while (azerty[i] != 0) {
-		if (azerty[i] == hex)
-			return LATIN_KEYBOARD_AZERTY;
-		i++;
+	wchar_t buf[LOCALE_NAME_MAX_LENGTH];
+	memset(buf, 0, LOCALE_NAME_MAX_LENGTH * sizeof(wchar_t));
+	LCIDToLocaleName(MAKELCID(LOWORD(layouts[p_index]), SORT_DEFAULT), buf, LOCALE_NAME_MAX_LENGTH, 0);
+
+	memfree(layouts);
+
+	return String(buf).substr(0, 2);
+}
+
+String _get_full_layout_name_from_registry(HKL p_layout) {
+	String id = "SYSTEM\\CurrentControlSet\\Control\\Keyboard Layouts\\" + String::num_int64((int64_t)p_layout, 16, false).lpad(8, "0");
+	String ret;
+
+	HKEY hkey;
+	wchar_t layout_text[1024];
+	memset(layout_text, 0, 1024 * sizeof(wchar_t));
+
+	if (RegOpenKeyExW(HKEY_LOCAL_MACHINE, (LPCWSTR)id.c_str(), 0, KEY_QUERY_VALUE, &hkey) != ERROR_SUCCESS) {
+		return ret;
 	}
 
-	i = 0;
-	while (qwertz[i] != 0) {
-		if (qwertz[i] == hex)
-			return LATIN_KEYBOARD_QWERTZ;
-		i++;
+	DWORD buffer = 1024;
+	DWORD vtype = REG_SZ;
+	if (RegQueryValueExW(hkey, L"Layout Text", NULL, &vtype, (LPBYTE)layout_text, &buffer) == ERROR_SUCCESS) {
+		ret = String(layout_text);
 	}
+	RegCloseKey(hkey);
+	return ret;
+}
+
+String DisplayServerWindows::keyboard_get_layout_name(int p_index) const {
+	int layout_count = GetKeyboardLayoutList(0, NULL);
+
+	ERR_FAIL_INDEX_V(p_index, layout_count, "");
+
+	HKL *layouts = (HKL *)memalloc(layout_count * sizeof(HKL));
+	GetKeyboardLayoutList(layout_count, layouts);
 
-	i = 0;
-	while (dvorak[i] != 0) {
-		if (dvorak[i] == hex)
-			return LATIN_KEYBOARD_DVORAK;
-		i++;
+	String ret = _get_full_layout_name_from_registry(layouts[p_index]); // Try reading full name from Windows registry, fallback to locale name if failed (e.g. on Wine).
+	if (ret == String()) {
+		wchar_t buf[LOCALE_NAME_MAX_LENGTH];
+		memset(buf, 0, LOCALE_NAME_MAX_LENGTH * sizeof(wchar_t));
+		LCIDToLocaleName(MAKELCID(LOWORD(layouts[p_index]), SORT_DEFAULT), buf, LOCALE_NAME_MAX_LENGTH, 0);
+
+		wchar_t name[1024];
+		memset(name, 0, 1024 * sizeof(wchar_t));
+		GetLocaleInfoEx(buf, LOCALE_SLOCALIZEDDISPLAYNAME, (LPWSTR)&name, 1024);
+
+		ret = String(name);
 	}
+	memfree(layouts);
 
-	return LATIN_KEYBOARD_QWERTY;
+	return ret;
 }
 
 void DisplayServerWindows::process_events() {
diff --git a/platform/windows/display_server_windows.h b/platform/windows/display_server_windows.h
index caf8598dc2..995ced0809 100644
--- a/platform/windows/display_server_windows.h
+++ b/platform/windows/display_server_windows.h
@@ -523,7 +523,11 @@ public:
 
 	virtual void enable_for_stealing_focus(OS::ProcessID pid);
 
-	virtual LatinKeyboardVariant get_latin_keyboard_variant() const;
+	virtual int keyboard_get_layout_count() const;
+	virtual int keyboard_get_current_layout() const;
+	virtual void keyboard_set_current_layout(int p_index);
+	virtual String keyboard_get_layout_language(int p_index) const;
+	virtual String keyboard_get_layout_name(int p_index) const;
 
 	virtual void process_events();