SDL: don't bypass X11 WM compositor (koreader#1158)

Author: pazos

ffi-cdecl/SDL2_0_decl.c

@@ -146,6 +146,8 @@ cdecl_func(SDL_GetClipboardText)
 cdecl_func(SDL_SetClipboardText)
 cdecl_func(SDL_GetError)
 
+cdecl_func(SDL_SetHint)
+
 cdecl_func(SDL_NumJoysticks)
 cdecl_func(SDL_JoystickNameForIndex)
 cdecl_func(SDL_JoystickOpen)

ffi/SDL2_0.lua

@@ -104,8 +104,12 @@ function S.open(w, h, x, y)
         S.h = tonumber(os.getenv("EMULATE_READER_H")) or h or 800
     end
 
-    -- default behaviour of SDL 2.0 is to disable the screensaver. This turns it back on
+    -- Enable screensaver and X11 composition.
     SDL.SDL_EnableScreenSaver()
+    if SDL_Linked_Version_AtLeast(2, 0, 8) then
+        SDL.SDL_SetHint("SDL_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR", "0")
+    end
+
     -- set up screen (window)
     S.screen = SDL.SDL_CreateWindow("KOReader",
         tonumber(os.getenv("KOREADER_WINDOW_POS_X")) or x or SDL.SDL_WINDOWPOS_UNDEFINED,

ffi/SDL2_0_h.lua

@@ -745,6 +745,7 @@ SDL_bool SDL_HasClipboardText(void) __attribute__((visibility("default")));
 char *SDL_GetClipboardText(void) __attribute__((visibility("default")));
 int SDL_SetClipboardText(const char *) __attribute__((visibility("default")));
 const char *SDL_GetError(void) __attribute__((visibility("default")));
+SDL_bool SDL_SetHint(const char *, const char *) __attribute__((visibility("default")));
 int SDL_NumJoysticks(void) __attribute__((visibility("default")));
 const char *SDL_JoystickNameForIndex(int) __attribute__((visibility("default")));
 SDL_Joystick *SDL_JoystickOpen(int) __attribute__((visibility("default")));