diff --git a/config.lib b/config.lib
index f273a7278b..3857bb6fff 100644
--- a/config.lib
+++ b/config.lib
@@ -72,6 +72,7 @@ set_default() {
 	with_lzma="1"
 	with_lzo2="1"
 	with_xdg_basedir="1"
+	with_fcitx="1"
 	with_png="1"
 	enable_builtin_depend="1"
 	with_makedepend="0"
@@ -152,6 +153,7 @@ set_default() {
 		with_lzma
 		with_lzo2
 		with_xdg_basedir
+		with_fcitx
 		with_png
 		enable_builtin_depend
 		with_makedepend
@@ -364,6 +366,10 @@ detect_params() {
 			--without-libxdg-basedir)     with_xdg_basedir="0";;
 			--with-libxdg-basedir=*)      with_xdg_basedir="$optarg";;
 
+			--with-fcitx)                 with_fcitx="2";;
+			--without-fcitx)              with_fcitx="0";;
+			--with-fcitx=*)               with_fcitx="$optarg";;
+
 			--with-png)                   with_png="2";;
 			--without-png)                with_png="0";;
 			--with-png=*)                 with_png="$optarg";;
@@ -895,6 +901,7 @@ check_params() {
 	fi
 
 	detect_xdg_basedir
+	detect_fcitx
 	detect_png
 	detect_freetype
 	detect_fontconfig
@@ -2107,6 +2114,39 @@ EOL
 		fi
 	fi
 
+	if [ -n "$dbus_config" ]; then
+		CFLAGS="$CFLAGS -DWITH_DBUS"
+		CFLAGS="$CFLAGS `$dbus_config --cflags | tr '\n\r' '  '`"
+
+		if [ "$enable_static" != "0" ]; then
+			LIBS="$LIBS `$dbus_config --libs --static | tr '\n\r' '  '`"
+		else
+			LIBS="$LIBS `$dbus_config --libs | tr '\n\r' '  '`"
+		fi
+	fi
+
+	if [ -n "$x11_config" ]; then
+		CFLAGS="$CFLAGS -DWITH_X11"
+		CFLAGS="$CFLAGS `$x11_config --cflags | tr '\n\r' '  '`"
+
+		if [ "$enable_static" != "0" ]; then
+			LIBS="$LIBS `$x11_config --libs --static | tr '\n\r' '  '`"
+		else
+			LIBS="$LIBS `$x11_config --libs | tr '\n\r' '  '`"
+		fi
+	fi
+
+	if [ -n "$fcitx_config" ]; then
+		CFLAGS="$CFLAGS -DWITH_FCITX"
+		CFLAGS="$CFLAGS `$fcitx_config --cflags | tr '\n\r' '  '`"
+
+		if [ "$enable_static" != "0" ]; then
+			LIBS="$LIBS `$fcitx_config --libs --static | tr '\n\r' '  '`"
+		else
+			LIBS="$LIBS `$fcitx_config --libs | tr '\n\r' '  '`"
+		fi
+	fi
+
 	# 64bit machines need -D_SQ64
 	if [ "$cpu_type" = "64" ] && [ "$enable_universal" = "0" ]; then
 		CFLAGS="$CFLAGS -D_SQ64"
@@ -3207,6 +3247,27 @@ detect_xdg_basedir() {
 	detect_pkg_config "$with_xdg_basedir" "libxdg-basedir" "xdg_basedir_config" "1.2"
 }
 
+detect_fcitx() {
+	if ([ "$with_fcitx" = "1" ] && [ "$enable_dedicated" = "0" ]) || [ "$with_fcitx" = "2" ]; then
+		detect_pkg_config "$with_fcitx" "dbus-1" "dbus_config" "1.0" "1"
+		detect_pkg_config "$with_fcitx" "x11" "x11_config" "1.0" "1"
+		if [ -z "$dbus_config" ]; then
+			log 1 "checking fcitx... no dbus, skipping"
+			fcitx_config=""
+			dbus_config=""
+			x11_config=""
+			return 0
+		elif [ -z "$x11_config" ]; then
+			log 1 "checking fcitx... no x11, skipping"
+			fcitx_config=""
+			dbus_config=""
+			x11_config=""
+			return 0
+		fi
+	fi
+	detect_pkg_config "$with_fcitx" "fcitx" "fcitx_config" "4.0" "1"
+}
+
 detect_png() {
 	detect_pkg_config "$with_png" "libpng" "png_config" "1.2"
 }
diff --git a/src/video/sdl2_v.cpp b/src/video/sdl2_v.cpp
index 9f01295b81..1edd4879cd 100644
--- a/src/video/sdl2_v.cpp
+++ b/src/video/sdl2_v.cpp
@@ -23,8 +23,7 @@
 #include "../core/math_func.hpp"
 #include "../fileio_func.h"
 #include "../framerate_type.h"
-#include "../window_func.h"
-#include "../window_gui.h"
+#include "../scope.h"
 #include "sdl2_v.h"
 #include <SDL.h>
 #include <mutex>
@@ -35,6 +34,15 @@
 #include "../3rdparty/mingw-std-threads/mingw.condition_variable.h"
 #endif
 
+#if defined(WITH_FCITX)
+#include <fcitx/frontend.h>
+#include <dbus/dbus.h>
+#include <SDL_syswm.h>
+#include <X11/Xlib.h>
+#include <X11/keysym.h>
+#include <unistd.h>
+#endif
+
 #include "../safeguards.h"
 
 static FVideoDriver_SDL iFVideoDriver_SDL;
@@ -64,6 +72,191 @@ static int _window_size_h;
 
 static std::string _editing_text;
 
+static void SetTextInputRect();
+
+Point GetFocusedWindowCaret();
+Point GetFocusedWindowTopLeft();
+bool FocusedWindowIsConsole();
+bool EditBoxInGlobalFocus();
+
+#if defined(WITH_FCITX)
+static bool _fcitx_mode = false;
+static char _fcitx_service_name[64];
+static char _fcitx_ic_name[64];
+static DBusConnection *_fcitx_dbus_session_conn = nullptr;
+
+static void FcitxICMethod(const char *method)
+{
+	DBusMessage *msg = dbus_message_new_method_call(_fcitx_service_name, _fcitx_ic_name, "org.fcitx.Fcitx.InputContext", method);
+	if (!msg) return;
+	dbus_connection_send(_fcitx_dbus_session_conn, msg, NULL);
+	dbus_connection_flush(_fcitx_dbus_session_conn);
+	dbus_message_unref(msg);
+}
+
+static int GetXDisplayNum()
+{
+	const char *display = getenv("DISPLAY");
+	if (!display) return 0;
+	const char *colon = strchr(display, ':');
+	if (!colon) return 0;
+	return atoi(colon + 1);
+}
+
+static void FcitxDeinit() {
+	if (_fcitx_mode) {
+		FcitxICMethod("DestroyIC");
+		_fcitx_mode = false;
+	}
+	if (_fcitx_dbus_session_conn) {
+		dbus_connection_close(_fcitx_dbus_session_conn);
+		_fcitx_dbus_session_conn = nullptr;
+	}
+}
+
+static DBusHandlerResult FcitxDBusMessageFilter(DBusConnection *connection, DBusMessage *message, void *user_data)
+{
+	if (dbus_message_is_signal(message, "org.fcitx.Fcitx.InputContext", "CommitString")) {
+		DBusMessageIter iter;
+		const char *text = nullptr;
+		dbus_message_iter_init(message, &iter);
+		dbus_message_iter_get_basic(&iter, &text);
+
+		if (text != nullptr && EditBoxInGlobalFocus()) {
+			HandleTextInput(nullptr, true);
+			HandleTextInput(text);
+			SetTextInputRect();
+		}
+
+		return DBUS_HANDLER_RESULT_HANDLED;
+	}
+
+	if (dbus_message_is_signal(message, "org.fcitx.Fcitx.InputContext", "UpdatePreedit")) {
+		const char *text = nullptr;
+		int32 cursor;
+		if (!dbus_message_get_args(message, nullptr, DBUS_TYPE_STRING, &text, DBUS_TYPE_INT32, &cursor, DBUS_TYPE_INVALID)) return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+
+		if (text != nullptr && EditBoxInGlobalFocus()) {
+			HandleTextInput(text, true, text + min<uint>(cursor, strlen(text)));
+		}
+		return DBUS_HANDLER_RESULT_HANDLED;
+	}
+	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+static void FcitxInit()
+{
+	DBusError err;
+	dbus_error_init(&err);
+	_fcitx_dbus_session_conn = dbus_bus_get_private(DBUS_BUS_SESSION, &err);
+	if (dbus_error_is_set(&err)) {
+		dbus_error_free(&err);
+		return;
+	}
+	dbus_connection_set_exit_on_disconnect(_fcitx_dbus_session_conn, false);
+	seprintf(_fcitx_service_name, lastof(_fcitx_service_name), "org.fcitx.Fcitx-%d", GetXDisplayNum());
+
+	auto guard = scope_guard([]() {
+		if (!_fcitx_mode) FcitxDeinit();
+	});
+
+	int pid = getpid();
+	int id = -1;
+	uint32 enable, hk1sym, hk1state, hk2sym, hk2state;
+	DBusMessage *msg = dbus_message_new_method_call(_fcitx_service_name, "/inputmethod", "org.fcitx.Fcitx.InputMethod", "CreateICv3");
+	if (!msg) return;
+	auto guard1 = scope_guard([&]() {
+		dbus_message_unref(msg);
+	});
+	const char *name = "OpenTTD";
+	if (!dbus_message_append_args(msg, DBUS_TYPE_STRING, &name, DBUS_TYPE_INT32, &pid, DBUS_TYPE_INVALID)) return;
+	DBusMessage *reply = dbus_connection_send_with_reply_and_block(_fcitx_dbus_session_conn, msg, 100, nullptr);
+	if (!reply) return;
+	auto guard2 = scope_guard([&]() {
+		dbus_message_unref(reply);
+	});
+	if (!dbus_message_get_args(reply, nullptr, DBUS_TYPE_INT32, &id, DBUS_TYPE_BOOLEAN, &enable, DBUS_TYPE_UINT32, &hk1sym, DBUS_TYPE_UINT32, &hk1state, DBUS_TYPE_UINT32, &hk2sym, DBUS_TYPE_UINT32, &hk2state, DBUS_TYPE_INVALID)) return;
+
+	if (id < 0) return;
+
+	seprintf(_fcitx_ic_name, lastof(_fcitx_ic_name), "/inputcontext_%d", id);
+	dbus_bus_add_match(_fcitx_dbus_session_conn, "type='signal', interface='org.fcitx.Fcitx.InputContext'", nullptr);
+	dbus_connection_add_filter(_fcitx_dbus_session_conn, &FcitxDBusMessageFilter, nullptr, nullptr);
+	dbus_connection_flush(_fcitx_dbus_session_conn);
+
+	uint32 caps = CAPACITY_PREEDIT;
+	DBusMessage *msg2 = dbus_message_new_method_call(_fcitx_service_name, _fcitx_ic_name, "org.fcitx.Fcitx.InputContext", "SetCapacity");
+	if (!msg2) return;
+	auto guard3 = scope_guard([&]() {
+		dbus_message_unref(msg2);
+	});
+	if (!dbus_message_append_args(msg2, DBUS_TYPE_UINT32, &caps, DBUS_TYPE_INVALID)) return;
+	dbus_connection_send(_fcitx_dbus_session_conn, msg2, NULL);
+	dbus_connection_flush(_fcitx_dbus_session_conn);
+
+	SDL_EventState(SDL_SYSWMEVENT, 1);
+
+	_fcitx_mode = true;
+}
+
+static uint32 _fcitx_last_keycode;
+static uint32 _fcitx_last_keysym;
+static bool FcitxProcessKey(const SDL_Keysym &key)
+{
+	uint32 fcitx_mods = 0;
+	if (key.mod & KMOD_SHIFT) fcitx_mods |= FcitxKeyState_Shift;
+	if (key.mod & KMOD_CAPS)  fcitx_mods |= FcitxKeyState_CapsLock;
+	if (key.mod & KMOD_CTRL)  fcitx_mods |= FcitxKeyState_Ctrl;
+	if (key.mod & KMOD_ALT)   fcitx_mods |= FcitxKeyState_Alt;
+	if (key.mod & KMOD_NUM)   fcitx_mods |= FcitxKeyState_NumLock;
+	if (key.mod & KMOD_LGUI)  fcitx_mods |= FcitxKeyState_Super;
+	if (key.mod & KMOD_RGUI)  fcitx_mods |= FcitxKeyState_Meta;
+
+	int type = FCITX_PRESS_KEY;
+	uint32 event_time = 0;
+
+	DBusMessage *msg = dbus_message_new_method_call(_fcitx_service_name, _fcitx_ic_name, "org.fcitx.Fcitx.InputContext", "ProcessKeyEvent");
+	if (!msg) return false;
+	auto guard1 = scope_guard([&]() {
+		dbus_message_unref(msg);
+	});
+	if (!dbus_message_append_args(msg, DBUS_TYPE_UINT32, &_fcitx_last_keysym, DBUS_TYPE_UINT32, &_fcitx_last_keycode, DBUS_TYPE_UINT32, &fcitx_mods,
+			DBUS_TYPE_INT32, &type, DBUS_TYPE_UINT32, &event_time, DBUS_TYPE_INVALID)) return false;
+	DBusMessage *reply = dbus_connection_send_with_reply_and_block(_fcitx_dbus_session_conn, msg, 300, nullptr);
+	if (!reply) return false;
+	auto guard2 = scope_guard([&]() {
+		dbus_message_unref(reply);
+	});
+	uint32 handled = 0;
+	if (!dbus_message_get_args(reply, nullptr, DBUS_TYPE_INT32, &handled, DBUS_TYPE_INVALID)) return false;
+	return handled;
+}
+
+static void FcitxPoll()
+{
+	dbus_connection_read_write(_fcitx_dbus_session_conn, 0);
+	while (dbus_connection_dispatch(_fcitx_dbus_session_conn) == DBUS_DISPATCH_DATA_REMAINS) {}
+}
+
+static void FcitxFocusChange(bool focused)
+{
+	FcitxICMethod(focused ? "FocusIn" : "FocusOut");
+}
+
+static void FcitxSYSWMEVENT(const SDL_SysWMEvent &event)
+{
+	if (event.msg->subsystem != SDL_SYSWM_X11) return;
+	XEvent &xevent = event.msg->msg.x11.event;
+	if (xevent.type == KeyPress) {
+		KeySym keysym = XLookupKeysym(&xevent.xkey, 0);
+		_fcitx_last_keycode = xevent.xkey.keycode;
+		_fcitx_last_keysym = keysym;
+	}
+}
+#else
+const static bool _fcitx_mode = false;
+#endif
+
 void VideoDriver_SDL::MakeDirty(int left, int top, int width, int height)
 {
 	if (_num_dirty_rects < MAX_DIRTY_RECTS) {
@@ -362,21 +555,79 @@ bool VideoDriver_SDL::ClaimMousePointer()
 	return true;
 }
 
+static void StartTextInput()
+{
+#if defined(WITH_FCITX)
+	if (_fcitx_mode) {
+		return;
+	}
+#endif
+	SDL_StartTextInput();
+}
+
+static void StopTextInput()
+{
+#if defined(WITH_FCITX)
+	if (_fcitx_mode) {
+		return;
+	}
+#endif
+	SDL_StopTextInput();
+}
+
 static void SetTextInputRect()
 {
 	SDL_Rect winrect;
-	Point pt = _focused_window->GetCaretPosition();
-	winrect.x = _focused_window->left + pt.x;
-	winrect.y = _focused_window->top  + pt.y;
+	Point caret = GetFocusedWindowCaret();
+	Point win = GetFocusedWindowTopLeft();
+	winrect.x = win.x + caret.x;
+	winrect.y = win.y + caret.y;
 	winrect.w = 1;
 	winrect.h = FONT_HEIGHT_NORMAL;
+
+#if defined(WITH_FCITX)
+	if (_fcitx_mode) {
+		SDL_SysWMinfo info;
+		SDL_VERSION(&info.version);
+		if (!SDL_GetWindowWMInfo(_sdl_window, &info)) {
+			return;
+		}
+		int x = 0;
+		int y = 0;
+		if (info.subsystem == SDL_SYSWM_X11) {
+			Display *x_disp = info.info.x11.display;
+			Window x_win = info.info.x11.window;
+			XWindowAttributes attrib;
+			XGetWindowAttributes(x_disp, x_win, &attrib);
+			Window unused;
+			XTranslateCoordinates(x_disp, x_win, attrib.root, 0, 0, &x, &y, &unused);
+		} else {
+			SDL_GetWindowPosition(_sdl_window, &x, &y);
+		}
+		x += winrect.x;
+		y += winrect.y;
+		DBusMessage *msg = dbus_message_new_method_call(_fcitx_service_name, _fcitx_ic_name, "org.fcitx.Fcitx.InputContext", "SetCursorRect");
+		if (!msg) return;
+		auto guard = scope_guard([&]() {
+			dbus_message_unref(msg);
+		});
+		if (!dbus_message_append_args(msg, DBUS_TYPE_INT32, &x, DBUS_TYPE_INT32, &y, DBUS_TYPE_INT32, &winrect.w,
+				DBUS_TYPE_INT32, &winrect.h, DBUS_TYPE_INVALID)) return;
+		dbus_connection_send(_fcitx_dbus_session_conn, msg, NULL);
+		dbus_connection_flush(_fcitx_dbus_session_conn);
+		return;
+	}
+#endif
+
 	SDL_SetTextInputRect(&winrect);
 }
 
 void VideoDriver_SDL::EditBoxGainedFocus()
 {
 	if (!this->edit_box_focused) {
-		SDL_StartTextInput();
+		if (!_fcitx_mode) {
+			StartTextInput();
+		}
 		this->edit_box_focused = true;
 	}
 	SetTextInputRect();
@@ -385,7 +636,14 @@ void VideoDriver_SDL::EditBoxGainedFocus()
 void VideoDriver_SDL::EditBoxLostFocus()
 {
 	if (this->edit_box_focused) {
-		SDL_StopTextInput();
+		if (_fcitx_mode) {
+#if defined(WITH_FCITX)
+			FcitxICMethod("Reset");
+			FcitxICMethod("CloseIC");
+#endif
+		} else {
+			StopTextInput();
+		}
 		this->edit_box_focused = false;
 	}
 	/* Clear any marked string from the current edit box. */
@@ -525,8 +783,11 @@ static uint ConvertSdlKeycodeIntoMy(SDL_Keycode kc)
 
 int VideoDriver_SDL::PollEvent()
 {
-	SDL_Event ev;
+#if defined(WITH_FCITX)
+	if (_fcitx_mode) FcitxPoll();
+#endif
 
+	SDL_Event ev;
 	if (!SDL_PollEvent(&ev)) return -2;
 
 	switch (ev.type) {
@@ -584,6 +845,15 @@ int VideoDriver_SDL::PollEvent()
 			break;
 
 		case SDL_KEYDOWN: // Toggle full-screen on ALT + ENTER/F
+#if defined(WITH_FCITX)
+			if (_fcitx_mode && EditBoxInGlobalFocus() && !(FocusedWindowIsConsole() &&
+					ConvertSdlKeycodeIntoMy(SDL_GetKeyFromName(ev.text.text)) == WKC_BACKQUOTE)) {
+				if (FcitxProcessKey(ev.key.keysym)) {
+					/* key press handled by Fcitx */
+					break;
+				}
+			}
+#endif
 			if ((ev.key.keysym.mod & (KMOD_ALT | KMOD_GUI)) &&
 					(ev.key.keysym.sym == SDLK_RETURN || ev.key.keysym.sym == SDLK_f)) {
 				if (ev.key.repeat == 0) ToggleFullScreen(!_fullscreen);
@@ -603,14 +873,15 @@ int VideoDriver_SDL::PollEvent()
 					keycode & WKC_ALT ||
 					(keycode >= WKC_F1 && keycode <= WKC_F12) ||
 					!IsValidChar(character, CS_ALPHANUMERAL) ||
-					!this->edit_box_focused) {
+					!this->edit_box_focused ||
+					_fcitx_mode) {
 					HandleKeypress(keycode, character);
 				}
 			}
 			break;
 
 		case SDL_TEXTINPUT: {
-			if (EditBoxInGlobalFocus() && !(_focused_window->window_class == WC_CONSOLE &&
+			if (EditBoxInGlobalFocus() && !(FocusedWindowIsConsole() &&
 					ConvertSdlKeycodeIntoMy(SDL_GetKeyFromName(ev.text.text)) == WKC_BACKQUOTE)) {
 				HandleTextInput(nullptr, true);
 				HandleTextInput(ev.text.text);
@@ -652,9 +923,25 @@ int VideoDriver_SDL::PollEvent()
 				// mouse left the window, undraw cursor
 				UndrawMouseCursor();
 				_cursor.in_window = false;
+			} else if (ev.window.event == SDL_WINDOWEVENT_MOVED) {
+				if (_fcitx_mode) SetTextInputRect();
+			} else if (ev.window.event == SDL_WINDOWEVENT_FOCUS_GAINED) {
+#if defined(WITH_FCITX)
+				if (_fcitx_mode) FcitxFocusChange(true);
+#endif
+			} else if (ev.window.event == SDL_WINDOWEVENT_FOCUS_LOST) {
+#if defined(WITH_FCITX)
+				if (_fcitx_mode) FcitxFocusChange(false);
+#endif
 			}
 			break;
 		}
+
+		case SDL_SYSWMEVENT: {
+#if defined(WITH_FCITX)
+				if (_fcitx_mode) FcitxSYSWMEVENT(ev.syswm);
+#endif
+		}
 	}
 	return -1;
 }
@@ -690,11 +977,18 @@ const char *VideoDriver_SDL::Start(const char * const *parm)
 	SDL_StopTextInput();
 	this->edit_box_focused = false;
 
+#if defined(WITH_FCITX)
+	FcitxInit();
+#endif
+
 	return nullptr;
 }
 
 void VideoDriver_SDL::Stop()
 {
+#if defined(WITH_FCITX)
+	FcitxDeinit();
+#endif
 	SDL_QuitSubSystem(SDL_INIT_VIDEO);
 	if (SDL_WasInit(SDL_INIT_EVERYTHING) == 0) {
 		SDL_Quit(); // If there's nothing left, quit SDL
diff --git a/src/window.cpp b/src/window.cpp
index 92dc9981d3..710cd8562f 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -454,6 +454,21 @@ void SetFocusedWindow(Window *w)
 	if (_focused_window != nullptr) _focused_window->OnFocus(old_focused);
 }
 
+Point GetFocusedWindowCaret()
+{
+	return _focused_window->GetCaretPosition();
+}
+
+Point GetFocusedWindowTopLeft()
+{
+	return { _focused_window->left, _focused_window->top };
+}
+
+bool FocusedWindowIsConsole()
+{
+	return _focused_window && _focused_window->window_class == WC_CONSOLE;
+}
+
 /**
  * Check if an edit box is in global focus. That is if focused window
  * has a edit box as focused widget, or if a console is focused.