ui/chromeos/touch_exploration_controller.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 UI_CHROMEOS_TOUCH_EXPLORATION_CONTROLLER_H_
   6 #define UI_CHROMEOS_TOUCH_EXPLORATION_CONTROLLER_H_
   7
   8 #include "base/values.h"
   9 #include "ui/chromeos/ui_chromeos_export.h"
  10 #include "ui/events/event_rewriter.h"
  11 #include "ui/gfx/geometry/point.h"
  12
  13 namespace aura {
  14 class Window;
  15 }
  16
  17 namespace ui {
  18
  19 class Event;
  20
  21 // TouchExplorationController is used in tandem with "Spoken Feedback" to
  22 // make the touch UI accessible. TouchExplorationController rewrites the
  23 // incoming touch events as follows:
  24 // - When one finger is touching the screen, touch events are converted to mouse
  25 //   moves. This is the "Touch Exploration Mode". (The idea is that mouse moves
  26 //   will be subsequently used by another component to move focus between UI
  27 //   elements, and the elements will be read out to the user.)
  28 // - When more than one finger is touching the screen, touches from the
  29 //   first (i.e. "oldest") finger are ignored, and the other touches go through
  30 //   as is.
  31 // The caller is expected to retain ownership of instances of this class and
  32 // destroy them before |root_window| is destroyed.
  33 class UI_CHROMEOS_EXPORT TouchExplorationController :
  34     public ui::EventRewriter {
  35  public:
  36   explicit TouchExplorationController(aura::Window* root_window);
  37   virtual ~TouchExplorationController();
  38
  39  private:
  40   scoped_ptr<ui::Event> CreateMouseMoveEvent(const gfx::PointF& location,
  41                                              int flags);
  42
  43   void EnterTouchToMouseMode();
  44
  45   // Overridden from ui::EventRewriter
  46   virtual ui::EventRewriteStatus RewriteEvent(
  47       const ui::Event& event, scoped_ptr<ui::Event>* rewritten_event) OVERRIDE;
  48   virtual ui::EventRewriteStatus NextDispatchEvent(
  49       const ui::Event& last_event, scoped_ptr<ui::Event>* new_event) OVERRIDE;
  50
  51   // A set of touch ids for fingers currently touching the screen.
  52   std::vector<int> touch_ids_;
  53
  54   // Map of touch ids to their last known location.
  55   std::map<int, gfx::PointF> touch_locations_;
  56
  57   // Initialized from RewriteEvent() and dispatched in NextDispatchEvent().
  58   scoped_ptr<ui::Event> next_dispatch_event_;
  59
  60   aura::Window* root_window_;
  61
  62   DISALLOW_COPY_AND_ASSIGN(TouchExplorationController);
  63 };
  64
  65 }  // namespace ui
  66
  67 #endif  // UI_CHROMEOS_TOUCH_EXPLORATION_CONTROLLER_H_