TWin: Active borders and snap tiling

This commit is a squash of the commits of TDE/tdebase#331.

In short, this backports some improvements to existing electric border
functionality from KDE, adds the snap tiling (or aerosnap) feature and
brings rudimentary support for active corners, which will be fully
implemented in a later PR.

The options dialog and the documentation has been updated to reflect
these changes.

Additionally, a new relevant option is introduced: an option for
restoring the original size of maximized/tiled windows when the user
starts dragging them. The option is set to be off by default,
preserving the traditional behaviour of KDE 3.x/TDE.

Last but not least, the term "electric" in relation to borders and
corners is replaced by "active" for clarity to the users.

Signed-off-by: Mavridis Philippe <mavridisf@gmail.com>

1 files changed, 31 insertions, 25 deletions

diff --git a/twin/layers.cpp b/twin/layers.cpp
index 143d826d5..17068a675 100644
--- a/twin/layers.cpp
+++ b/twin/layers.cpp
@@ -129,43 +129,50 @@ void Workspace::updateStackingOrder( bool propagate_new_clients )
 void Workspace::propagateClients( bool propagate_new_clients )
     {
     Window *cl; // MW we should not assume WId and Window to be compatible
-                                // when passig pointers around.
+                                // when passing pointers around.
 
     // restack the windows according to the stacking order
-#if 0
-    Window* new_stack = new Window[ stacking_order.count() + 2 ];
-    int pos = 0;
-#endif
     NET::WindowType t;
     Window shadow;
     Window *dock_shadow_stack, *window_stack;
     int i, numDocks, pos, topmenu_space_pos;
- 
+
+    // Dock Stack size magic number explanation:
+    // -> (count * 2) because we might need to also store the shadow window
+    //    for each dock window (Chakra shadow patch, introduced in 9cc1e2c1aa)
     dock_shadow_stack = new Window[ stacking_order.count() * 2 ];
-    window_stack = new Window[ stacking_order.count() * 2 + 2 ];
+
+    // Window Stack size magic number explanation:
+    // -> (count * 2) because we might need to store shadow windows (see above)
+    // -> + 1 for supportWindow
+    // -> + 1 for topmenu_space
+    // -> + 8 for active borders
+    window_stack = new Window[ stacking_order.count() * 2 + 1 + 1 + 8 ];
     i = 0;
     pos = 0;
     topmenu_space_pos = 1; // not 0, that's supportWindow !!!
 
-    // Stack all windows under the support window. The support window is
-    // not used for anything (besides the NETWM property), and it's not shown,
-    // but it was lowered after twin startup. Stacking all clients below
-    // it ensures that no client will be ever shown above override-redirect
-    // windows (e.g. popups).
-#if 0
-    new_stack[ pos++ ] = supportWindow->winId();
-    int topmenu_space_pos = 1; // not 0, that's supportWindow !!!
-#endif
+    // Stack active windows under the support window.
+    /* The support window is not used for anything (besides the NETWM property),
+     * and it's not shown, but it was lowered after TWin startup.
+     * Stacking all clients below it ensures that no client will be ever shown
+     * above override-redirect windows (e.g. popups).
+     */
+    for (int i = 0; i < ACTIVE_BORDER_COUNT; ++i)
+    {
+        if (active_windows[i] != None)
+        {
+            window_stack[pos++] = active_windows[i];
+        }
+    }
+
+    // Stack all windows under the support and active borders windows.
     window_stack[pos++] = supportWindow->winId();
     for( ClientList::ConstIterator it = stacking_order.fromLast();
          it != stacking_order.end();
          --it )
         {
-#if 0
-        new_stack[ pos++ ] = (*it)->frameId();
-        if( (*it)->belongsToLayer() >= DockLayer )
-            topmenu_space_pos = pos;
-#endif
+
 	t = (*it)->windowType();
 	switch (t)
 		{
@@ -202,15 +209,14 @@ void Workspace::propagateClients( bool propagate_new_clients )
         new_stack[ topmenu_space_pos ] = topmenu_space->winId();
 #endif
             window_stack[ i ] = window_stack[ i - 1 ];
-	window_stack[ topmenu_space_pos ] = topmenu_space->winId();
-        ++pos;
+            window_stack[ topmenu_space_pos ] = topmenu_space->winId();
+            ++pos;
         }
 #if 0
     // TODO isn't it too inefficient to restart always all clients?
     // TODO don't restack not visible windows?
     assert( new_stack[ 0 ] = supportWindow->winId());
-#endif
-#if 0
+
     XRestackWindows(tqt_xdisplay(), new_stack, pos);
     delete [] new_stack;
 #endif