Added support for SDL_SetWindowKeyboardGrab():

- With SDL_SetWindowKeyboardGrab() function, we are able to replace
  low level XGrabKeyboard() and XUngrabKeyboard() making the code
  much more portable. Also it fixes a couple of corner cases where
  window focus was lost when concurrent X applications tried to grab
  the keyboard.

- Client no longer depends on libx11 directly and with a future
  commit we can work on Wayland support as mentioned in #7.

- Requires SDL >= 2.0.16.

Author: mbroemme

README.md

@@ -113,8 +113,7 @@ without chroma subsampling for sharp and crystal clear text.
 * Fully CLI based customization. User can specify all required parameters via
   command line switches, allow perfect integration into different window
   managers.
-* Desktop in window support with [XGrabKeyboard](https://tronche.com/gui/x/xlib/input/XGrabKeyboard.html)
-  and [XUngrabKeyboard](https://tronche.com/gui/x/xlib/input/XUngrabKeyboard.html)
+* Desktop in window support with [SDL_SetWindowKeyboardGrab](https://wiki.libsdl.org/SDL_SetWindowKeyboardGrab)
   while leaving mouse pointer ungrabbed. Supporting Alt+Tab and Windows special
   keys grab, even if assigned to the window manager.
 * SDL window is created without `SDL_WINDOW_RESIZABLE` flag set, so window
@@ -160,14 +159,14 @@ without chroma subsampling for sharp and crystal clear text.
 # Building
 
 VDI Stream Client uses GNU Build System to configure, build and install the
-application. It requires `sdl2`, `sdl2_ttf`, `libx11`, `libglvnd`, `libusb`,
-`usbredir` and the [Parsec SDK](https://github.com/parsec-cloud/parsec-sdk).
-The build system will search the SDK first in build directory and use DSO
-linking, the resulting binary will be redistributable but you need to ship
-Parsec library somehow. If not found, it will search in system-wide include and
-library directories and link accordingly, binary may not be redistributable.
-For build and install use the commands below and if `--prefix=/usr` is used,
-the `make install` command must be run as root user.
+application. It requires `sdl2`, `sdl2_ttf`, `libglvnd`, `libusb`, `usbredir`
+and the [Parsec SDK](https://github.com/parsec-cloud/parsec-sdk). The build
+system will search the SDK first in build directory and use DSO linking, the
+resulting binary will be redistributable but you need to ship Parsec library
+somehow. If not found, it will search in system-wide include and library
+directories and link accordingly, binary may not be redistributable. For build
+and install use the commands below and if `--prefix=/usr` is used, the
+`make install` command must be run as root user.
 
 ```
 git clone https://github.com/parsec-cloud/parsec-sdk

configure.ac

@@ -21,14 +21,11 @@ PKG_PROG_PKG_CONFIG
 AC_CHECK_HEADER([dlfcn.h], [], [AC_MSG_ERROR([*** dlfcn.h is required, install glibc header files])])
 AC_CHECK_LIB([dl], [dlopen], [], [AC_MSG_ERROR([*** dlopen is required, install glibc library files])])
 
-# checking for libx11 library.
-PKG_CHECK_MODULES([X11], [x11])
-
 # checking for libglvnd library.
 PKG_CHECK_MODULES([GL], [gl])
 
 # checking for sdl2 library.
-PKG_CHECK_MODULES([SDL2], [sdl2 >= 2.0.5])
+PKG_CHECK_MODULES([SDL2], [sdl2 >= 2.0.16])
 
 # checking for sdl2_ttf library.
 PKG_CHECK_MODULES([SDL2_TTF], [SDL2_ttf >= 2.0.5])

src/parsec.c

@@ -127,7 +127,6 @@ Sint32 vdi_stream_client__render_text(void *opaque, char *text) {
 Sint32 vdi_stream_client__event_loop(vdi_config_s *vdi_config) {
 	struct parsec_context_s parsec_context = {0};
 	struct redirect_context_s redirect_context[USB_MAX] = {0};
-	SDL_bool focus = SDL_FALSE;
 	SDL_bool grab_forced = SDL_FALSE;
 	Uint32 wait_time = 0;
 	Uint32 last_time = 0;
@@ -421,10 +420,6 @@ Sint32 vdi_stream_client__event_loop(vdi_config_s *vdi_config) {
 					vdi_stream_client__render_text(&parsec_context, "Closing...");
 					break;
 				case SDL_KEYUP:
-
-					/* TODO: we need to re-grab keyboard later. (workaround for buggy x11 and sdl) */
-					focus = SDL_FALSE;
-
 					pmsg.type = MESSAGE_KEYBOARD;
 					pmsg.keyboard.code = (ParsecKeycode) msg.key.keysym.scancode;
 					pmsg.keyboard.mod = msg.key.keysym.mod;
@@ -574,27 +569,15 @@ Sint32 vdi_stream_client__event_loop(vdi_config_s *vdi_config) {
 					break;
 				case SDL_WINDOWEVENT:
 					switch (msg.window.event) {
-						case SDL_WINDOWEVENT_FOCUS_GAINED:
+						case SDL_WINDOWEVENT_ENTER:
 							SDL_EventState(SDL_KEYDOWN, SDL_ENABLE);
 							SDL_EventState(SDL_KEYUP, SDL_ENABLE);
-							XGrabKeyboard(wm_info.info.x11.display, wm_info.info.x11.window, False, GrabModeAsync, GrabModeAsync, CurrentTime);
-
-							/* TODO: copy client to host clipboard. (workaround for buggy x11 and sdl) */
-							if (vdi_config->clipboard == 1 && SDL_HasClipboardText() == SDL_TRUE) {
-								ParsecClientSendUserData(parsec_context.parsec, PARSEC_CLIPBOARD_MSG, SDL_GetClipboardText());
-							}
-
+							SDL_SetWindowKeyboardGrab(parsec_context.window, SDL_TRUE);
 							break;
-						case SDL_WINDOWEVENT_FOCUS_LOST:
+						case SDL_WINDOWEVENT_LEAVE:
 							SDL_EventState(SDL_KEYDOWN, SDL_DISABLE);
 							SDL_EventState(SDL_KEYUP, SDL_DISABLE);
-							XUngrabKeyboard(wm_info.info.x11.display, CurrentTime);
-							break;
-						case SDL_WINDOWEVENT_ENTER:
-							parsec_context.focus = SDL_TRUE;
-							break;
-						case SDL_WINDOWEVENT_LEAVE:
-							parsec_context.focus = SDL_FALSE;
+							SDL_SetWindowKeyboardGrab(parsec_context.window, SDL_FALSE);
 							break;
 					}
 					break;
@@ -663,9 +646,6 @@ Sint32 vdi_stream_client__event_loop(vdi_config_s *vdi_config) {
 				default:
 					break;
 			}
-
-			/* TODO: we need to re-grab keyboard later. (workaround for buggy x11 and sdl) */
-			focus = SDL_FALSE;
 		}
 
 		/* TODO: check if we need to grab input to force decoder initialization. (workaround for buggy parsec sdk) */
@@ -711,17 +691,11 @@ Sint32 vdi_stream_client__event_loop(vdi_config_s *vdi_config) {
 			parsec_context.window_height = parsec_context.client_status.decoder->height;
 		}
 
-		/* check if we need to regrab keyboard on modifier keypress. */
-		if (focus == SDL_FALSE && (SDL_GetWindowFlags(parsec_context.window) & SDL_WINDOW_INPUT_FOCUS) != 0) {
-			XGrabKeyboard(wm_info.info.x11.display, wm_info.info.x11.window, False, GrabModeAsync, GrabModeAsync, CurrentTime);
-			focus = SDL_TRUE;
-		}
-
 		SDL_Delay(1);
 	}
 
 	/* already release any grabbed keyboard because thread termination can take some time. */
-	XUngrabKeyboard(wm_info.info.x11.display, CurrentTime);
+	SDL_SetWindowGrab(parsec_context.window, SDL_FALSE);
 
 	/* stop network threads for usb redirection. */
 	if (vdi_config->usb_devices[0].vendor != 0) {