x11: enable window transparency

CHANGES.md

@@ -16,6 +16,7 @@
 - INPUT: Map clear button to DEL key.
 - LINUX/X11: Add RetroArch logo to window title bar.
 - LINUX/X11: Input driver now supports new lightgun code.
+- LINUX/X11: Support window transparency.
 - LOBBIES: Fix for crash on join netplay rooms via touch / glui.
 - LOCALIZATION: Update Italian translation.
 - LOCALIZATION: Update Japanese translation.
@@ -33,6 +34,7 @@
 - WINDOWS: Use configured OSD/text message color on GDI driver.
 - WINDOWS/XINPUT: Populate XInput VID/PID from DInput so autoconfig doesn't rely solely on joypad names
 - WINDOWS: Improve version reporting under System Information.
+- WINDOWS: Support window transparency.
 
 # 1.6.9
 - COMMON: Small memory leak.

Makefile.common

@@ -900,10 +900,11 @@ ifeq ($(HAVE_X11), 1)
    OBJ += input/common/input_x11_common.o \
           input/drivers/x11_input.o \
           gfx/common/x11_common.o \
-			 gfx/common/xinerama_common.o
+          gfx/common/xinerama_common.o \
+          gfx/display_servers/dispserv_x11.o
 
    LIBS += $(X11_LIBS) $(XEXT_LIBS) $(XF86VM_LIBS) $(XINERAMA_LIBS)
-   DEFINES += $(X11_CFLAGS) $(XEXT_CFLAGS) $(XF86VM_CFLAGS) $(XINERAMA_CFLAGS)
+   DEFINES += -DHAVE_X11 $(X11_CFLAGS) $(XEXT_CFLAGS) $(XF86VM_CFLAGS) $(XINERAMA_CFLAGS)
 ifeq ($(HAVE_XCB),1)
    LIBS    += -lX11-xcb
 endif

gfx/display_servers/dispserv_win32.c

@@ -45,7 +45,7 @@ static bool win32_set_window_opacity(void *data, unsigned opacity)
 
 #if defined(_WIN32_WINNT) && _WIN32_WINNT >= 0x0500
    /* Set window transparency on Windows 2000 and above */
-   return SetLayeredWindowAttributes(hwnd, 0, opacity, LWA_ALPHA);
+   return SetLayeredWindowAttributes(hwnd, 0, (255 * opacity) / 100, LWA_ALPHA);
 #else
    return false;
 #endif

gfx/display_servers/dispserv_x11.c

@@ -0,0 +1,64 @@
+/*  RetroArch - A frontend for libretro.
+ *  Copyright (C) 2010-2014 - Hans-Kristian Arntzen
+ *  Copyright (C) 2011-2017 - Daniel De Matteis
+ *  Copyright (C) 2016-2017 - Brad Parker
+ *
+ *  RetroArch is free software: you can redistribute it and/or modify it under the terms
+ *  of the GNU General Public License as published by the Free Software Found-
+ *  ation, either version 3 of the License, or (at your option) any later version.
+ *
+ *  RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ *  PURPOSE.  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with RetroArch.
+ *  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "../video_display_server.h"
+#include "../common/x11_common.h"
+#include "../../configuration.h"
+
+typedef struct
+{
+   unsigned opacity;
+} dispserv_x11_t;
+
+static void* x11_display_server_init(void)
+{
+   dispserv_x11_t *dispserv = (dispserv_x11_t*)calloc(1, sizeof(*dispserv));
+
+   return dispserv;
+}
+
+static void x11_display_server_destroy(void)
+{
+
+}
+
+static bool x11_set_window_opacity(void *data, unsigned opacity)
+{
+   dispserv_x11_t *serv = (dispserv_x11_t*)data;
+   Atom net_wm_opacity = XInternAtom(g_x11_dpy, "_NET_WM_WINDOW_OPACITY", False);
+   Atom cardinal = XInternAtom(g_x11_dpy, "CARDINAL", False);
+   settings_t *settings = config_get_ptr();
+
+   serv->opacity = opacity;
+
+   opacity = opacity * ((unsigned)-1 / 100.0);
+
+   if (opacity == (unsigned)-1)
+      XDeleteProperty(g_x11_dpy, g_x11_win, net_wm_opacity);
+  else
+      XChangeProperty(g_x11_dpy, g_x11_win, net_wm_opacity, cardinal, 32, PropModeReplace, (const unsigned char*)&opacity, 1);
+
+   return true;
+}
+
+const video_display_server_t dispserv_x11 = {
+   x11_display_server_init,
+   x11_display_server_destroy,
+   x11_set_window_opacity,
+   "x11"
+};
+

gfx/drivers_context/x_ctx.c

@@ -623,7 +623,10 @@ static bool gfx_ctx_x_set_video_mode(void *data,
    int (*old_handler)(Display*, XErrorEvent*) = NULL;
    gfx_ctx_x_data_t *x       = (gfx_ctx_x_data_t*)data;
    Atom net_wm_icon = XInternAtom(g_x11_dpy, "_NET_WM_ICON", False);
+   Atom net_wm_opacity = XInternAtom(g_x11_dpy, "_NET_WM_WINDOW_OPACITY", False);
    Atom cardinal = XInternAtom(g_x11_dpy, "CARDINAL", False);
+   settings_t *settings = config_get_ptr();
+   unsigned opacity = settings->uints.video_window_opacity * ((unsigned)-1 / 100.0);
 
    frontend_driver_install_signal_handler();
 
@@ -713,6 +716,9 @@ static bool gfx_ctx_x_set_video_mode(void *data,
 
    XChangeProperty(g_x11_dpy, g_x11_win, net_wm_icon, cardinal, 32, PropModeReplace, (const unsigned char*)retroarch_icon_data, sizeof(retroarch_icon_data) / sizeof(*retroarch_icon_data));
 
+   if (opacity < (unsigned)-1)
+      XChangeProperty(g_x11_dpy, g_x11_win, net_wm_opacity, cardinal, 32, PropModeReplace, (const unsigned char*)&opacity, 1);
+
    switch (x_api)
    {
       case GFX_CTX_OPENGL_API:

gfx/video_display_server.c

@@ -29,11 +29,16 @@ void* video_display_server_init(void)
 
    switch (type)
    {
-      case RARCH_DISPLAY_WIN32:
 #if defined(_WIN32) && !defined(_XBOX)
+      case RARCH_DISPLAY_WIN32:
          current_display_server = &dispserv_win32;
-#endif
          break;
+#endif
+#if defined(HAVE_X11)
+      case RARCH_DISPLAY_X11:
+         current_display_server = &dispserv_x11;
+         break;
+#endif
       default:
          current_display_server = &dispserv_null;
          break;

gfx/video_display_server.h

@@ -36,6 +36,7 @@ void video_display_server_destroy(void);
 bool video_display_server_set_window_opacity(unsigned opacity);
 
 extern const video_display_server_t dispserv_win32;
+extern const video_display_server_t dispserv_x11;
 extern const video_display_server_t dispserv_null;
 
 RETRO_END_DECLS

menu/menu_setting.c

@@ -1836,7 +1836,7 @@ void general_write_handler(void *data)
 #endif
          break;
       case MENU_ENUM_LABEL_VIDEO_WINDOW_OPACITY:
-         video_display_server_set_window_opacity((255 * settings->uints.video_window_opacity) / 100);
+         video_display_server_set_window_opacity(settings->uints.video_window_opacity);
          break;
       default:
          break;