Refactor: Shelf Widget

ash/wm/shelf_layout_manager.h

-// Copyright (c) 2012 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_SHELF_LAYOUT_MANAGER_H_
-#define ASH_WM_SHELF_LAYOUT_MANAGER_H_
-
-#include "ash/ash_export.h"
-#include "ash/launcher/launcher.h"
-#include "ash/shelf_types.h"
-#include "ash/shell_observer.h"
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "base/logging.h"
-#include "base/observer_list.h"
-#include "base/timer.h"
-#include "ui/aura/client/activation_change_observer.h"
-#include "ui/aura/layout_manager.h"
-#include "ui/gfx/insets.h"
-#include "ui/gfx/rect.h"
-
-namespace aura {
-class RootWindow;
-}
-
-namespace ui {
-class GestureEvent;
-}
-
-namespace ash {
-class ScreenAsh;
-namespace internal {
-
-class ShelfLayoutManagerTest;
-class StatusAreaWidget;
-class WorkspaceController;
-
-// ShelfLayoutManager is the layout manager responsible for the launcher and
-// status widgets. The launcher is given the total available width and told the
-// width of the status area. This allows the launcher to draw the background and
-// layout to the status area.
-// To respond to bounds changes in the status area StatusAreaLayoutManager works
-// closely with ShelfLayoutManager.
-class ASH_EXPORT ShelfLayoutManager :
-    public aura::LayoutManager,
-    public ash::ShellObserver,
-    public aura::client::ActivationChangeObserver {
- public:
-  class ASH_EXPORT Observer {
-   public:
-    // Called when the target ShelfLayoutManager will be deleted.
-    virtual void WillDeleteShelf() {}
-
-    // Called when the visibility change is scheduled.
-    virtual void WillChangeVisibilityState(ShelfVisibilityState new_state) {}
-
-    // Called when the auto hide state is changed.
-    virtual void OnAutoHideStateChanged(ShelfAutoHideState new_state) {}
-  };
-
-  // We reserve a small area at the bottom of the workspace area to ensure that
-  // the bottom-of-window resize handle can be hit.
-  static const int kWorkspaceAreaBottomInset;
-
-  // Size of the shelf when auto-hidden.
-  static const int kAutoHideSize;
-
-  explicit ShelfLayoutManager(StatusAreaWidget* status);
-  virtual ~ShelfLayoutManager();
-
-  // Sets the ShelfAutoHideBehavior. See enum description for details.
-  void SetAutoHideBehavior(ShelfAutoHideBehavior behavior);
-  ShelfAutoHideBehavior auto_hide_behavior() const {
-    return auto_hide_behavior_;
-  }
-
-  // Sets the alignment. Returns true if the alignment is changed. Otherwise,
-  // returns false.
-  bool SetAlignment(ShelfAlignment alignment);
-  ShelfAlignment GetAlignment() const { return alignment_; }
-
-  void set_workspace_controller(WorkspaceController* controller) {
-    workspace_controller_ = controller;
-  }
-
-  views::Widget* launcher_widget() {
-    return launcher_ ? launcher_->widget() : NULL;
-  }
-  const views::Widget* launcher_widget() const {
-    return launcher_ ? launcher_->widget() : NULL;
-  }
-  StatusAreaWidget* status_area_widget() { return status_area_widget_; }
-
-  bool in_layout() const { return in_layout_; }
-
-  // Returns whether the shelf and its contents (launcher, status) are visible
-  // on the screen.
-  bool IsVisible() const;
-
-  // The launcher is typically created after the layout manager.
-  void SetLauncher(Launcher* launcher);
-  Launcher* launcher() { return launcher_; }
-
-  // Returns the ideal bounds of the shelf assuming it is visible.
-  gfx::Rect GetIdealBounds();
-
-  // Stops any animations and sets the bounds of the launcher and status
-  // widgets.
-  void LayoutShelf();
-
-  // Returns shelf visibility state based on current value of auto hide
-  // behavior setting.
-  ShelfVisibilityState CalculateShelfVisibility();
-
-  // Returns shelf visibility state based on current value of auto hide
-  // behavior setting.
-  ShelfVisibilityState CalculateShelfVisibilityWhileDragging();
-
-  // Updates the visibility state.
-  void UpdateVisibilityState();
-
-  // Invoked by the shelf/launcher when the auto-hide state may have changed.
-  void UpdateAutoHideState();
-
-  ShelfVisibilityState visibility_state() const {
-    return state_.visibility_state;
-  }
-  ShelfAutoHideState auto_hide_state() const { return state_.auto_hide_state; }
-
-  // Sets whether any windows overlap the shelf. If a window overlaps the shelf
-  // the shelf renders slightly differently.
-  void SetWindowOverlapsShelf(bool value);
-  bool window_overlaps_shelf() const { return window_overlaps_shelf_; }
-
-  void AddObserver(Observer* observer);
-  void RemoveObserver(Observer* observer);
-
-  // Gesture dragging related functions:
-  void StartGestureDrag(const ui::GestureEvent& gesture);
-  enum DragState {
-    DRAG_SHELF,
-    DRAG_TRAY
-  };
-  // Returns DRAG_SHELF if the gesture should continue to drag the entire shelf.
-  // Returns DRAG_TRAY if the gesture can start dragging the tray-bubble from
-  // this point on.
-  DragState UpdateGestureDrag(const ui::GestureEvent& gesture);
-  void CompleteGestureDrag(const ui::GestureEvent& gesture);
-  void CancelGestureDrag();
-
-  // Overridden from 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 visible) OVERRIDE;
-  virtual void SetChildBounds(aura::Window* child,
-                              const gfx::Rect& requested_bounds) OVERRIDE;
-
-  // Overridden from ash::ShellObserver:
-  virtual void OnLockStateChanged(bool locked) OVERRIDE;
-
-  // Overriden from aura::client::ActivationChangeObserver:
-  virtual void OnWindowActivated(aura::Window* gained_active,
-                                 aura::Window* lost_active) OVERRIDE;
-
-  // TODO(harrym|oshima): These templates will be moved to
-  // new Shelf class.
-  // A helper function that provides a shortcut for choosing
-  // values specific to a shelf alignment.
-  template<typename T>
-  T SelectValueForShelfAlignment(T bottom, T left, T right, T top) const {
-    switch (alignment_) {
-      case SHELF_ALIGNMENT_BOTTOM:
-        return bottom;
-      case SHELF_ALIGNMENT_LEFT:
-        return left;
-      case SHELF_ALIGNMENT_RIGHT:
-        return right;
-      case SHELF_ALIGNMENT_TOP:
-        return top;
-    }
-    NOTREACHED();
-    return right;
-  }
-
-  template<typename T>
-  T PrimaryAxisValue(T horizontal, T vertical) const {
-    return IsHorizontalAlignment() ? horizontal : vertical;
-  }
-
-  // Is the shelf's alignment horizontal?
-  bool IsHorizontalAlignment() const;
-
-  // Returns a ShelfLayoutManager on the display which has a launcher for
-  // given |window|. See RootWindowController::ForLauncher for more info.
-  static ShelfLayoutManager* ForLauncher(aura::Window* window);
-
- private:
-  class AutoHideEventFilter;
-  class UpdateShelfObserver;
-  friend class ash::ScreenAsh;
-  friend class ShelfLayoutManagerTest;
-
-  struct TargetBounds {
-    TargetBounds();
-
-    float opacity;
-    gfx::Rect launcher_bounds_in_root;
-    gfx::Rect status_bounds_in_root;
-    gfx::Insets work_area_insets;
-  };
-
-  struct State {
-    State() : visibility_state(SHELF_VISIBLE),
-              auto_hide_state(SHELF_AUTO_HIDE_HIDDEN),
-              is_screen_locked(false) {}
-
-    // Returns true if the two states are considered equal. As
-    // |auto_hide_state| only matters if |visibility_state| is
-    // |SHELF_AUTO_HIDE|, Equals() ignores the |auto_hide_state| as
-    // appropriate.
-    bool Equals(const State& other) const {
-      return other.visibility_state == visibility_state &&
-          (visibility_state != SHELF_AUTO_HIDE ||
-           other.auto_hide_state == auto_hide_state) &&
-          other.is_screen_locked == is_screen_locked;
-    }
-
-    ShelfVisibilityState visibility_state;
-    ShelfAutoHideState auto_hide_state;
-    bool is_screen_locked;
-  };
-
-  // Sets the visibility of the shelf to |state|.
-  void SetState(ShelfVisibilityState visibility_state);
-
-  // Stops any animations.
-  void StopAnimating();
-
-  // Returns the width (if aligned to the side) or height (if aligned to the
-  // bottom).
-  void GetShelfSize(int* width, int* height);
-
-  // Insets |bounds| by |inset| on the edge the shelf is aligned to.
-  void AdjustBoundsBasedOnAlignment(int inset, gfx::Rect* bounds) const;
-
-  // Calculates the target bounds assuming visibility of |visible|.
-  void CalculateTargetBounds(const State& state, TargetBounds* target_bounds);
-
-  // Updates the target bounds if a gesture-drag is in progress. This is only
-  // used by |CalculateTargetBounds()|.
-  void UpdateTargetBoundsForGesture(TargetBounds* target_bounds) const;
-
-  // Updates the background of the shelf.
-  void UpdateShelfBackground(BackgroundAnimator::ChangeType type);
-
-  // Returns whether the launcher should draw a background.
-  bool GetLauncherPaintsBackground() const;
-
-  // Updates the auto hide state immediately.
-  void UpdateAutoHideStateNow();
-
-  // Returns the AutoHideState. This value is determined from the launcher and
-  // tray.
-  ShelfAutoHideState CalculateAutoHideState(
-      ShelfVisibilityState visibility_state) const;
-
-  // Updates the hit test bounds override for launcher and status area.
-  void UpdateHitTestBounds();
-
-  // Returns true if |window| is a descendant of the shelf.
-  bool IsShelfWindow(aura::Window* window);
-
-  int GetWorkAreaSize(const State& state, int size) const;
-
-  // The RootWindow is cached so that we don't invoke Shell::GetInstance() from
-  // our destructor. We avoid that as at the time we're deleted Shell is being
-  // deleted too.
-  aura::RootWindow* root_window_;
-
-  // True when inside LayoutShelf method. Used to prevent calling LayoutShelf
-  // again from SetChildBounds().
-  bool in_layout_;
-
-  // See description above setter.
-  ShelfAutoHideBehavior auto_hide_behavior_;
-
-  ShelfAlignment alignment_;
-
-  // Current state.
-  State state_;
-
-  Launcher* launcher_;
-  StatusAreaWidget* status_area_widget_;
-
-  WorkspaceController* workspace_controller_;
-
-  // Do any windows overlap the shelf? This is maintained by WorkspaceManager.
-  bool window_overlaps_shelf_;
-
-  base::OneShotTimer<ShelfLayoutManager> auto_hide_timer_;
-
-  // EventFilter used to detect when user moves the mouse over the launcher to
-  // trigger showing the launcher.
-  scoped_ptr<AutoHideEventFilter> event_filter_;
-
-  ObserverList<Observer> observers_;
-
-  // The shelf reacts to gesture-drags, and can be set to auto-hide for certain
-  // gestures. Some shelf behaviour (e.g. visibility state, background color
-  // etc.) are affected by various stages of the drag. The enum keeps track of
-  // the present status of the gesture drag.
-  enum GestureDragStatus {
-    GESTURE_DRAG_NONE,
-    GESTURE_DRAG_IN_PROGRESS,
-    GESTURE_DRAG_COMPLETE_IN_PROGRESS
-  };
-  GestureDragStatus gesture_drag_status_;
-
-  // Tracks the amount of the drag. The value is only valid when
-  // |gesture_drag_status_| is set to GESTURE_DRAG_IN_PROGRESS.
-  float gesture_drag_amount_;
-
-  // Manage the auto-hide state during the gesture.
-  ShelfAutoHideState gesture_drag_auto_hide_state_;
-
-  // Used to delay updating shelf background.
-  UpdateShelfObserver* update_shelf_observer_;
-
-  DISALLOW_COPY_AND_ASSIGN(ShelfLayoutManager);
-};
-
-}  // namespace internal
-}  // namespace ash
-
-#endif  // ASH_WM_SHELF_LAYOUT_MANAGER_H_