athena/home/home_card_gesture_manager.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef ATHENA_HOME_HOME_CARD_GESTURE_MANAGER_H_
   6 #define ATHENA_HOME_HOME_CARD_GESTURE_MANAGER_H_
   7
   8 #include "athena/home/public/home_card.h"
   9 #include "athena/athena_export.h"
  10 #include "ui/gfx/geometry/rect.h"
  11
  12 namespace ui {
  13 class GestureEvent;
  14 }
  15
  16 namespace athena {
  17
  18 // Handles the touch gestures over the home card.
  19 class ATHENA_EXPORT HomeCardGestureManager {
  20  public:
  21   class Delegate {
  22    public:
  23     // Called when the gesture has ended. The state of the home card will
  24     // end up with |final_state|.
  25     virtual void OnGestureEnded(HomeCard::State final_state) = 0;
  26
  27     // Called when the gesture position is updated so that |delegate| should
  28     // update the visual. The arguments represent the state of the current
  29     // gesture position is switching from |from_state| to |to_state|, and
  30     // the level of the progress is at |progress|, which is 0 to 1.
  31     // |from_state| and |to_state| could be same. For example, if the user moves
  32     // the finger down to the bottom of the screen, both states are MINIMIZED.
  33     // In that case |progress| is 0.
  34     virtual void OnGestureProgressed(
  35         HomeCard::State from_state,
  36         HomeCard::State to_state,
  37         float progress) = 0;
  38   };
  39
  40   HomeCardGestureManager(Delegate* delegate,
  41                          const gfx::Rect& screen_bounds);
  42   ~HomeCardGestureManager();
  43
  44   void ProcessGestureEvent(ui::GestureEvent* event);
  45
  46  private:
  47   // Get the closest state from the last position.
  48   HomeCard::State GetClosestState() const;
  49
  50   // Update the current position and emits OnGestureProgressed().
  51   void UpdateScrollState(const ui::GestureEvent& event);
  52
  53   Delegate* delegate_;  // Not owned.
  54   HomeCard::State last_state_;
  55
  56   // The offset from the top edge of the home card and the initial position of
  57   // gesture.
  58   int y_offset_;
  59
  60   // The estimated height of the home card after the last touch event.
  61   int last_estimated_height_;
  62
  63   // The bounds of the screen to compute the home card bounds.
  64   gfx::Rect screen_bounds_;
  65
  66   DISALLOW_COPY_AND_ASSIGN(HomeCardGestureManager);
  67 };
  68
  69 }  // namespace athena
  70
  71 #endif  // ATHENA_HOME_HOME_CARD_GESTURE_MANAGER_H_