frames.c: Re-implement directional maximization when double-clicking

the frame edges.

Fixes #620.

Author: mtwebster

src/core/window.c

@@ -6476,10 +6476,15 @@ update_move (MetaWindow  *window,
 
   /* shake loose (unmaximize) maximized or tiled window if dragged beyond
    * the threshold in the Y direction. Tiled windows can also be pulled
-   * loose via X motion.
+   * loose via X motion. The fact you can 'slide' one-way-maximized
+   * windows along their maximized edge is useful but it's easy to accidentally
+   * pull them loose while doing so. Double their thresholds to make this less
+   * likely to happen.
    */
 
   if ((META_WINDOW_MAXIMIZED (window) && ABS (dy) >= shake_threshold) ||
+      (META_WINDOW_MAXIMIZED_HORIZONTALLY (window) && ABS (dx) >= (shake_threshold * 2)) ||
+      (META_WINDOW_MAXIMIZED_VERTICALLY (window) && ABS (dy) >= (shake_threshold * 2)) ||
       (META_WINDOW_TILED (window) && (MAX (ABS (dx), ABS (dy)) >= shake_threshold)))
     {
       double prop;

src/ui/frames.c

@@ -1094,6 +1094,27 @@ get_button_number (const ClutterEvent *event)
   return -1;
 }
 
+static gboolean
+meta_frame_double_click_edge_event (MetaUIFrame        *frame,
+                                    const ClutterEvent *event,
+                                    MetaFrameControl    control)
+{
+    switch (control) {
+        case META_FRAME_CONTROL_RESIZE_N:
+        case META_FRAME_CONTROL_RESIZE_S:
+            return meta_frame_titlebar_event (frame,
+                                              event,
+                                              C_DESKTOP_TITLEBAR_ACTION_TOGGLE_MAXIMIZE_VERTICALLY);
+        case META_FRAME_CONTROL_RESIZE_E:
+        case META_FRAME_CONTROL_RESIZE_W:
+            return meta_frame_titlebar_event (frame,
+                                              event,
+                                              C_DESKTOP_TITLEBAR_ACTION_TOGGLE_MAXIMIZE_HORIZONTALLY);
+        default:
+            return FALSE;
+        }
+}
+
 static gboolean
 meta_frame_left_click_event (MetaUIFrame        *frame,
                              const ClutterEvent *event)
@@ -1238,6 +1259,16 @@ handle_press_event (MetaUIFrame        *frame,
       return meta_frame_double_click_event (frame, event);
     }
 
+  if ((control == META_FRAME_CONTROL_RESIZE_N ||
+       control == META_FRAME_CONTROL_RESIZE_S ||
+       control == META_FRAME_CONTROL_RESIZE_E ||
+       control == META_FRAME_CONTROL_RESIZE_W) &&
+       action == META_ACTION_DOUBLE_CLICK)
+    {
+      meta_x11_wm_end_grab_op (frame->frames->x11_display, evtime);
+      return meta_frame_double_click_edge_event (frame, event, control);
+    }
+
   if (meta_x11_wm_get_grab_op (frame->frames->x11_display) != META_GRAB_OP_NONE)
     return FALSE; /* already up to something */