Stick windows to sides of workspaces

ash/wm/dock/docked_window_layout_manager.h

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ASH_WM_DOCK_DOCKED_WINDOW_LAYOUT_MANAGER_H_
+#define ASH_WM_DOCK_DOCKED_WINDOW_LAYOUT_MANAGER_H_
+
+#include "ash/ash_export.h"
+#include "ash/shelf/shelf_layout_manager_observer.h"
+#include "ash/shell_observer.h"
+#include "ash/wm/dock/dock_types.h"
+#include "ash/wm/property_util.h"
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "ui/aura/client/activation_change_observer.h"
+#include "ui/aura/layout_manager.h"
+#include "ui/aura/window_observer.h"
+#include "ui/keyboard/keyboard_controller_observer.h"
+
+namespace aura {
+class Window;
+}
+
+namespace gfx {
+class Point;
+class Rect;
+}
+
+namespace ash {
+class Launcher;
+
+namespace internal {
+class ShelfLayoutManager;
+
+// DockedWindowLayoutManager is responsible for organizing windows when they are
+// docked to the side of a screen. It is associated with a specific container
+// window (i.e. kShellWindowId_DockContainer) and controls the layout of any
+// windows added to that container.
+//
+// The constructor takes a |dock_container| argument which is expected to set
+// its layout manager to this instance, e.g.:
+// dock_container->SetLayoutManager(
+//     new DockedWindowLayoutManager(dock_container));
+
+class ASH_EXPORT DockedWindowLayoutManager
+    : public aura::LayoutManager,
+      public ash::ShellObserver,
+      public aura::WindowObserver,
+      public aura::client::ActivationChangeObserver,
+      public keyboard::KeyboardControllerObserver,
+      public ash::ShelfLayoutManagerObserver {
+ public:
+  explicit DockedWindowLayoutManager(aura::Window* dock_container);
+  virtual ~DockedWindowLayoutManager();
+
+  // Called by a DockedWindowResizer to update which window is being dragged.
+  void StartDragging(aura::Window* window);
+  void FinishDragging();
+
+  // Returns true if a window is touching the side of the screen except 2 cases:
+  // when some other windows are already docked on the other side or
+  // when launcher (shelf) is aligned on the same side.
+  static bool ShouldWindowDock(aura::Window* window,
+                               const gfx::Point& location);
+
+  ash::Launcher* launcher() { return launcher_; }
+  void SetLauncher(ash::Launcher* launcher);
+
+  // Used to snap docked windows to the side of screen during drag.
+  DockedAlignment alignment() const { return alignment_; }
+
+  // Currently dragged window should be able to dock on another screen
+  aura::Window* dragged_window() const { return dragged_window_;}
+
+  // aura::LayoutManager:
+  virtual void OnWindowResized() OVERRIDE;
+  virtual void OnWindowAddedToLayout(aura::Window* child) OVERRIDE;
+  virtual void OnWillRemoveWindowFromLayout(aura::Window* child) OVERRIDE;
+  virtual void OnWindowRemovedFromLayout(aura::Window* child) OVERRIDE;
+  virtual void OnChildWindowVisibilityChanged(aura::Window* child,
+                                              bool visibile) OVERRIDE;
+  virtual void SetChildBounds(aura::Window* child,
+                              const gfx::Rect& requested_bounds) OVERRIDE;
+
+  // ash::ShellObserver:
+  virtual void OnShelfAlignmentChanged(aura::RootWindow* root_window) OVERRIDE;
+
+  // aura::WindowObserver:
+  virtual void OnWindowPropertyChanged(aura::Window* window,
+                                       const void* key,
+                                       intptr_t old) OVERRIDE;
+
+  // aura::client::ActivationChangeObserver:
+  virtual void OnWindowActivated(aura::Window* gained_active,
+                                 aura::Window* lost_active) OVERRIDE;
+
+  // ShelfLayoutManagerObserver:
+  virtual void WillChangeVisibilityState(
+      ShelfVisibilityState new_state) OVERRIDE;
+
+ private:
+  friend class DockedWindowLayoutManagerTest;
+  friend class DockedWindowResizerTest;
+
+  // Minimize / restore window and relayout.
+  void MinimizeWindow(aura::Window* window);
+  void RestoreWindow(aura::Window* window);
+
+  // Called whenever the window layout might change.
+  void Relayout();
+
+  // Called whenever the window stacking order needs to be updated (e.g. focus
+  // changes or a window is moved).
+  void UpdateStacking(aura::Window* active_window);
+
+  // keyboard::KeyboardControllerObserver:
+  virtual void OnKeyboardBoundsChanging(
+      const gfx::Rect& keyboard_bounds) OVERRIDE;
+
+  // Parent window associated with this layout manager.
+  aura::Window* dock_container_;
+  // Protect against recursive calls to Relayout().
+  bool in_layout_;
+  // The docked window being dragged.
+  aura::Window* dragged_window_;
+  // The launcher we are observing for launcher icon changes.
+  Launcher* launcher_;
+  // The shelf layout manager being observed for visibility changes.
+  ShelfLayoutManager* shelf_layout_manager_;
+  // Tracks the visibility of the shelf. Defaults to false when there is no
+  // shelf.
+  bool shelf_hidden_;
+
+  // Side of the screen that the dock is positioned at.
+  DockedAlignment alignment_;
+
+  DISALLOW_COPY_AND_ASSIGN(DockedWindowLayoutManager);
+};
+
+}  // namespace internal
+}  // namespace ash
+
+#endif  // ASH_WM_DOCK_DOCKED_WINDOW_LAYOUT_MANAGER_H_