Fixed Window::EnableKeyRepeat on Linux

git-svn-id: https://sfml.svn.sourceforge.net/svnroot/sfml/trunk@1039 4e206d99-4929-0410-ac5d-dfc041789085

src/SFML/Window/Linux/WindowImplX11.cpp

@@ -362,28 +362,51 @@ void WindowImplX11::Display()
 ////////////////////////////////////////////////////////////
 void WindowImplX11::ProcessEvents()
 {
+    // This function implements a workaround to properly discard
+    // repeated key events when necessary. The problem is that the
+    // system's key events policy doesn't match SFML's one: X server will generate
+    // both repeated KeyPress and KeyRelease events when maintaining a key down, while
+    // SFML only wants repeated KeyPress events. Thus, we have to:
+    // - Discard duplicated KeyRelease events when EnableKeyRepeat is true
+    // - Discard both duplicated KeyPress and KeyRelease events when EnableKeyRepeat is false
+
+
     // Process any event in the queue matching our window
     XEvent Event;
-    while (XCheckIfEvent(ourDisplay, &Event, &WindowImplX11::CheckEvent, reinterpret_cast<XPointer>(myWindow)))
+    while (XCheckWindowEvent(ourDisplay, myWindow, ourEventMask, &Event))
     {
-        // Filter repeated key events
+        // Detect repeated key events
+        if ((Event.type == KeyPress) || (Event.type == KeyRelease))
+        {
+            if (Event.xkey.keycode < 256)
+            {
+                // To detect if it is a repeated key event, we check the current state of the key.
+                // - If the state is "down", KeyReleased events must obviously be discarded.
+                // - KeyPress events are a little bit harder to handle: they depend on the EnableKeyRepeat state,
+                //   and we need to properly forward the first one.
+                char Keys[32];
+                XQueryKeymap(ourDisplay, Keys);
+                if (Keys[Event.xkey.keycode >> 3] & (1 << (Event.xkey.keycode % 8)))
+                {
+                    // KeyRelease event + key down = repeated event --> discard
                     if (Event.type == KeyRelease)
                     {
-            if (XPending(ourDisplay))
+                        myLastKeyReleaseEvent = Event;
+                        continue;
+                    }
+
+                    // KeyPress event + key repeat disabled + matching KeyRelease event = repeated event --> discard
+                    if ((Event.type == KeyPress) && !myKeyRepeat &&
+                        (myLastKeyReleaseEvent.xkey.keycode == Event.xkey.keycode) &&
+                        (myLastKeyReleaseEvent.xkey.time == Event.xkey.time))
                     {
-                XEvent NextEvent;
-                XPeekEvent(ourDisplay, &NextEvent);
-                if ((NextEvent.type         == KeyPress)           &&
-                    (NextEvent.xkey.keycode == Event.xkey.keycode) &&
-                    (NextEvent.xkey.time    == Event.xkey.time))
-                {
-                    if (!myKeyRepeat)
-                        XNextEvent(ourDisplay, &NextEvent);
                         continue;
                     }
                 }
             }
+        }
 
+        // Process the event
         ProcessEvent(Event);
    }
 }
@@ -709,6 +732,9 @@ bool WindowImplX11::CreateContext(const VideoMode& Mode, XVisualInfo& ChosenVisu
 ////////////////////////////////////////////////////////////
 void WindowImplX11::Initialize()
 {
+    // Make sure the "last key release" is initialized with invalid values
+    myLastKeyReleaseEvent.type = -1;
+
     // Get the atom defining the close event
     myAtomClose = XInternAtom(ourDisplay, "WM_DELETE_WINDOW", false);
     XSetWMProtocols(ourDisplay, myWindow, &myAtomClose, 1);
@@ -802,17 +828,6 @@ void WindowImplX11::CleanUp()
 }
 
 
-////////////////////////////////////////////////////////////
-/// Filter the received events
-/// (only allow those matching a specific window)
-////////////////////////////////////////////////////////////
-Bool WindowImplX11::CheckEvent(::Display*, XEvent* Event, XPointer UserData)
-{
-    // Just check if the event matches our window
-    return Event->xany.window == reinterpret_cast< ::Window >(UserData);
-}
-
-
 ////////////////////////////////////////////////////////////
 /// Process an incoming event from the window
 ////////////////////////////////////////////////////////////

src/SFML/Window/Linux/WindowImplX11.hpp

@@ -200,18 +200,6 @@ private :
     ////////////////////////////////////////////////////////////
     void CleanUp();
 
-    ////////////////////////////////////////////////////////////
-    /// Filter the received events
-    /// (only allow those matching a specific window)
-    ///
-    /// \param Event :    Event to filter
-    /// \param UserData : Data passed to the function (here : the window to compare)
-    ///
-    /// \return True if the event belongs to the specified window
-    ///
-    ////////////////////////////////////////////////////////////
-    static Bool CheckEvent(::Display*, XEvent* Event, XPointer UserData);
-
     ////////////////////////////////////////////////////////////
     /// Process an incoming event from the window
     ///
@@ -267,6 +255,7 @@ private :
     Cursor     myHiddenCursor;        ///< As X11 doesn't provide cursor hidding, we must create a transparent one
     XIC        myInputContext;        ///< Input context used to get unicode input in our window
     bool       myKeyRepeat;           ///< Is the KeyRepeat feature enabled ?
+    XEvent     myLastKeyReleaseEvent; ///< Last key release event we received (needed for discarding repeated key events)
 };
 
 } // namespace priv