Workaround for IME on Linux(fixes #29 #7106):

    Workaround for supporting input method frameworks like SCIM,
    IBus, Fcitx, etc.

    The locale is set when the application starts.

    Workaround for input when the input context within the specified
    input method is not available.

3 files changed, 129 insertions, 10 deletions

diff --git a/platform/x11/godot_x11.cpp b/platform/x11/godot_x11.cpp
index b293b1bebb..6f418b213f 100644
--- a/platform/x11/godot_x11.cpp
+++ b/platform/x11/godot_x11.cpp
@@ -28,6 +28,7 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 #include <limits.h>
+#include <locale.h>
 #include <stdlib.h>
 #include <unistd.h>
 
@@ -38,6 +39,8 @@ int main(int argc, char *argv[]) {
 
 	OS_X11 os;
 
+	setlocale(LC_CTYPE, "");
+
 	char *cwd = (char *)malloc(PATH_MAX);
 	getcwd(cwd, PATH_MAX);
 
diff --git a/platform/x11/os_x11.cpp b/platform/x11/os_x11.cpp
index 2eebc96d2c..aa20030606 100644
--- a/platform/x11/os_x11.cpp
+++ b/platform/x11/os_x11.cpp
@@ -93,6 +93,7 @@ const char *OS_X11::get_audio_driver_name(int p_driver) const {
 
 void OS_X11::initialize(const VideoMode &p_desired, int p_video_driver, int p_audio_driver) {
 
+	long im_event_mask = 0;
 	last_button_state = 0;
 
 	xmbstring = NULL;
@@ -113,7 +114,10 @@ void OS_X11::initialize(const VideoMode &p_desired, int p_video_driver, int p_au
 	/** XLIB INITIALIZATION **/
 	x11_display = XOpenDisplay(NULL);
 
-	char *modifiers = XSetLocaleModifiers("@im=none");
+	char *modifiers = XSetLocaleModifiers("");
+	if (modifiers == NULL) {
+		modifiers = XSetLocaleModifiers("@im=none");
+	}
 	if (modifiers == NULL) {
 		WARN_PRINT("Error setting locale modifiers");
 	}
@@ -153,6 +157,14 @@ void OS_X11::initialize(const VideoMode &p_desired, int p_video_driver, int p_au
 		WARN_PRINT("XOpenIM failed");
 		xim_style = 0L;
 	} else {
+		::XIMCallback im_destroy_callback;
+		im_destroy_callback.client_data = (::XPointer)(this);
+		im_destroy_callback.callback = (::XIMProc)(xim_destroy_callback);
+		if (XSetIMValues(xim, XNDestroyCallback, &im_destroy_callback,
+					NULL) != NULL) {
+			WARN_PRINT("Error setting XIM destroy callback");
+		}
+
 		::XIMStyles *xim_styles = NULL;
 		xim_style = 0L;
 		char *imvalret = NULL;
@@ -303,7 +315,8 @@ void OS_X11::initialize(const VideoMode &p_desired, int p_video_driver, int p_au
 						  StructureNotifyMask |
 						  SubstructureNotifyMask | SubstructureRedirectMask |
 						  FocusChangeMask | PropertyChangeMask |
-						  ColormapChangeMask | OwnerGrabButtonMask;
+						  ColormapChangeMask | OwnerGrabButtonMask |
+						  im_event_mask;
 
 	XChangeWindowAttributes(x11_display, x11_window, CWEventMask, &new_attr);
 
@@ -327,6 +340,16 @@ void OS_X11::initialize(const VideoMode &p_desired, int p_video_driver, int p_au
 	if (xim && xim_style) {
 
 		xic = XCreateIC(xim, XNInputStyle, xim_style, XNClientWindow, x11_window, XNFocusWindow, x11_window, (char *)NULL);
+		if (XGetICValues(xic, XNFilterEvents, &im_event_mask, NULL) != NULL) {
+			WARN_PRINT("XGetICValues couldn't obtain XNFilterEvents value");
+			XDestroyIC(xic);
+			xic = NULL;
+		}
+		if (xic) {
+			XSetICFocus(xic);
+		} else {
+			WARN_PRINT("XCreateIC couldn't create xic");
+		}
 	} else {
 
 		xic = NULL;
@@ -445,6 +468,30 @@ void OS_X11::initialize(const VideoMode &p_desired, int p_video_driver, int p_au
 	_ensure_data_dir();
 }
 
+void OS_X11::xim_destroy_callback(::XIM im, ::XPointer client_data,
+		::XPointer call_data) {
+	WARN_PRINT("Input method stopped");
+	OS_X11 *os = reinterpret_cast<OS_X11 *>(client_data);
+	os->xim = NULL;
+	os->xic = NULL;
+}
+
+void OS_X11::set_ime_position(short x, short y) {
+	if (xic) {
+		::XPoint spot;
+		spot.x = x;
+		spot.y = y;
+		XVaNestedList preedit_attr = XVaCreateNestedList(0,
+				XNSpotLocation, &spot,
+				NULL);
+		XSetICValues(xic,
+				XNPreeditAttributes, preedit_attr,
+				NULL);
+		XFree(preedit_attr);
+	}
+	return;
+}
+
 void OS_X11::finalize() {
 
 	if (main_loop)
@@ -492,8 +539,12 @@ void OS_X11::finalize() {
 			XcursorImageDestroy(img[i]);
 	};
 
-	XDestroyIC(xic);
-	XCloseIM(xim);
+	if (xic) {
+		XDestroyIC(xic);
+	}
+	if (xim) {
+		XCloseIM(xim);
+	}
 
 	XCloseDisplay(x11_display);
 	if (xmbstring)
@@ -1041,11 +1092,61 @@ void OS_X11::handle_key_event(XKeyEvent *p_event, bool p_echo) {
 		xmblen = 8;
 	}
 
+	keysym_unicode = keysym_keycode;
+
 	if (xkeyevent->type == KeyPress && xic) {
 
 		Status status;
-		do {
+#ifdef X_HAVE_UTF8_STRING
+		int utf8len = 8;
+		char *utf8string = (char *)memalloc(sizeof(char) * utf8len);
+		int utf8bytes = Xutf8LookupString(xic, xkeyevent, utf8string,
+				utf8len - 1, &keysym_unicode, &status);
+		if (status == XBufferOverflow) {
+			utf8len = utf8bytes + 1;
+			utf8string = (char *)memrealloc(utf8string, utf8len);
+			utf8bytes = Xutf8LookupString(xic, xkeyevent, utf8string,
+					utf8len - 1, &keysym_unicode, &status);
+		}
+		utf8string[utf8bytes] = '\0';
+
+		if (status == XLookupChars) {
+			bool keypress = xkeyevent->type == KeyPress;
+			unsigned int keycode = KeyMappingX11::get_keycode(keysym_keycode);
+			String tmp;
+			tmp.parse_utf8(utf8string, utf8bytes);
+			for (int i = 0; i < tmp.length(); i++) {
+				Ref<InputEventKey> k;
+				k.instance();
+				if (keycode == 0 && tmp[i] == 0) {
+					continue;
+				}
+
+				get_key_modifier_state(xkeyevent->state, k);
+
+				k->set_unicode(tmp[i]);
+
+				k->set_pressed(keypress);
+
+				if (keycode >= 'a' && keycode <= 'z')
+					keycode -= 'a' - 'A';
+				k->set_scancode(keycode);
 
+				k->set_echo(p_echo);
+
+				if (k->get_scancode() == KEY_BACKTAB) {
+					//make it consistent across platforms.
+					k->set_scancode(KEY_TAB);
+					k->set_shift(true);
+				}
+
+				input->parse_input_event(k);
+			}
+			return;
+		}
+		memfree(utf8string);
+#else
+		do {
 			int mnbytes = XmbLookupString(xic, xkeyevent, xmbstring, xmblen - 1, &keysym_unicode, &status);
 			xmbstring[mnbytes] = '\0';
 
@@ -1054,6 +1155,7 @@ void OS_X11::handle_key_event(XKeyEvent *p_event, bool p_echo) {
 				xmbstring = (char *)memrealloc(xmbstring, xmblen);
 			}
 		} while (status == XBufferOverflow);
+#endif
 	}
 
 	/* Phase 2, obtain a pigui keycode from the keysym */
@@ -1082,11 +1184,6 @@ void OS_X11::handle_key_event(XKeyEvent *p_event, bool p_echo) {
 
 	bool keypress = xkeyevent->type == KeyPress;
 
-	if (xkeyevent->type == KeyPress && xic) {
-		if (XFilterEvent((XEvent *)xkeyevent, x11_window))
-			return;
-	}
-
 	if (keycode == 0 && unicode == 0)
 		return;
 
@@ -1253,6 +1350,10 @@ void OS_X11::process_xevents() {
 		XEvent event;
 		XNextEvent(x11_display, &event);
 
+		if (XFilterEvent(&event, None)) {
+			continue;
+		}
+
 		switch (event.type) {
 			case Expose:
 				Main::force_redraw();
@@ -1295,6 +1396,9 @@ void OS_X11::process_xevents() {
 							ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
 							GrabModeAsync, GrabModeAsync, x11_window, None, CurrentTime);
 				}
+				if (xic) {
+					XSetICFocus(xic);
+				}
 				break;
 
 			case FocusOut:
@@ -1308,9 +1412,17 @@ void OS_X11::process_xevents() {
 					}
 					XUngrabPointer(x11_display, CurrentTime);
 				}
+				if (xic) {
+					XUnsetICFocus(xic);
+				}
 				break;
 
 			case ConfigureNotify:
+				if (xic) {
+					//  Not portable.
+					set_ime_position(0, 1);
+				}
+
 				/* call resizeGLScene only if our window-size changed */
 
 				if ((event.xconfigure.width == current_videomode.width) &&
diff --git a/platform/x11/os_x11.h b/platform/x11/os_x11.h
index d62186e5bd..b253934a05 100644
--- a/platform/x11/os_x11.h
+++ b/platform/x11/os_x11.h
@@ -113,6 +113,10 @@ class OS_X11 : public OS_Unix {
 	::XIC xic;
 	::XIM xim;
 	::XIMStyle xim_style;
+	static void xim_destroy_callback(::XIM im, ::XPointer client_data,
+			::XPointer call_data);
+	void set_ime_position(short x, short y);
+
 	Point2i last_mouse_pos;
 	bool last_mouse_pos_valid;
 	Point2i last_click_pos;