Side Slide Gestures for Accessibility

ui/chromeos/touch_exploration_controller.h

Index: ui/chromeos/touch_exploration_controller.h
diff --git a/ui/chromeos/touch_exploration_controller.h b/ui/chromeos/touch_exploration_controller.h
index e809bcd7b9378f0232a2137e4bd0f29e4f605f5a..0bf0890eb1a7fe36cea42935c178caca43a88358 100644
--- a/ui/chromeos/touch_exploration_controller.h
+++ b/ui/chromeos/touch_exploration_controller.h
@@ -26,9 +26,20 @@ class GestureEvent;
 class GestureProviderAura;
 class TouchEvent;
 
+// A delegate to handle commands in response to detected accessibility gesture
+// events.
+class TouchExplorationControllerDelegate {
+ public:
+  virtual ~TouchExplorationControllerDelegate() {}
+
+  virtual void const PlayVolumeAdjustSound() = 0;
+  virtual void AdjustSound(float volume) = 0;
+};
+
 // TouchExplorationController is used in tandem with "Spoken Feedback" to
-// make the touch UI accessible. Gestures are mapped to accessiblity key
-// shortcuts.
+// make the touch UI accessible. Gestures performed in the middle of the screen
+// are mapped to accessiblity key shortcuts while gestures performed on the edge
+// of the screen can change settings.
 //
 // ** Short version **
 //
@@ -40,7 +51,10 @@ class TouchEvent;
 // right would correspond to the keyboard short cut shift+search+right.
 // When two or more fingers are pressed initially, from then on the events
 // are passed through, but with the initial finger removed - so if you swipe
-// down with two fingers, the running app will see a one-finger swipe.
+// down with two fingers, the running app will see a one-finger swipe. Slide
+// gestures performed on the edge of the screen can change settings
+// continuously. For example, sliding a finger along the right side of the
+// screen will change the volume.
 //
 // ** Long version **
 //
@@ -91,6 +105,24 @@ class TouchEvent;
 // adds a third finger while in two to one finger mode, all fingers and touch
 // events are passed through from then on.
 //
+// If the user places a finger on the edge of the screen and moves their finger
+// past slop, a slide gesture is performed. The user can then slide one finger
+// along an edge of the screen and continuously control a setting. Once the user
+// enters this state, the boundaries that define an edge expand so that the user
+// can now adjust the setting within a slightly bigger width along the screen.
+// If the user exits this area without lifting their finger, they will not be
+// able to perform any actions, however if they keep their finger down and
+// return to the "hot edge," then they can still adjust the setting. In order to
+// perform other touch accessibility movements, the user must lift their finger.
+// If additional fingers are added while in this state, the user will transition
+// to passthrough.
+//
+// Currently, only the right edge is mapped to control the volume. Volume
+// control along the edge of the screen is directly proportional to where the
+// user's finger is located on the screen. The top right corner of the screen
+// automatically sets the volume to 100% and the bottome right corner of the
+// screen automatically sets the volume to 0% once the user has moved past slop.
+//
 // Once touch exploration mode has been activated,
 // it remains in that mode until all fingers have been released.
 //
@@ -100,7 +132,9 @@ class UI_CHROMEOS_EXPORT TouchExplorationController
     : public ui::EventRewriter,
       public ui::GestureProviderAuraClient {
  public:
-  explicit TouchExplorationController(aura::Window* root_window);
+  explicit TouchExplorationController(
+      aura::Window* root_window,
+      ui::TouchExplorationControllerDelegate* delegate);
   virtual ~TouchExplorationController();
 
   void CallTapTimerNowForTesting();
@@ -108,9 +142,11 @@ class UI_CHROMEOS_EXPORT TouchExplorationController
   void SetEventHandlerForTesting(ui::EventHandler* event_handler_for_testing);
   bool IsInNoFingersDownStateForTesting() const;
   bool IsInGestureInProgressStateForTesting() const;
+  bool IsInSlideGestureStateForTesting() const;
   // VLOGs should be suppressed in tests that generate a lot of logs,
   // for example permutations of nine touch events.
   void SuppressVLOGsForTesting(bool suppress);
+  gfx::Rect BoundsOfRootWindowInDIPForTesting();
 
  private:
   // Overridden from ui::EventRewriter
@@ -141,6 +177,8 @@ class UI_CHROMEOS_EXPORT TouchExplorationController
       const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
   ui::EventRewriteStatus InWaitForRelease(
       const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
+  ui::EventRewriteStatus InSlideGesture(
+      const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
 
   // This timer is started every time we get the first press event, and
   // it fires after the double-click timeout elapses (300 ms by default).
@@ -164,6 +202,8 @@ class UI_CHROMEOS_EXPORT TouchExplorationController
 
   void OnSwipeEvent(ui::GestureEvent* swipe_gesture);
 
+  void SideSlideControl(ui::GestureEvent* gesture);
+
   // Dispatches the keyboard short cut Shift+Search+<arrow key>
   // outside the event rewritting flow.
   void DispatchShiftSearchKeyEvent(const ui::KeyboardCode direction);
@@ -177,6 +217,8 @@ class UI_CHROMEOS_EXPORT TouchExplorationController
   // default value.
   void ResetToNoFingersDown();
 
+  void PlaySoundForTimer();
+
   enum State {
     // No fingers are down and no events are pending.
     NO_FINGERS_DOWN,
@@ -243,8 +285,28 @@ class UI_CHROMEOS_EXPORT TouchExplorationController
     // generally useful for developing new features, because it creates a
     // simple way to handle a dead end in user flow.
     WAIT_FOR_RELEASE,
+
+    // If the user is within the given bounds from an edge of the screen, not
+    // including corners, then the resulting movements will be interpreted as
+    // slide gestures.
+    SLIDE_GESTURE,
+  };
+
+  enum ScreenLocation {
+    // Hot "edges" of the screen are each represented by a respective bit.
+    RIGHT_EDGE = 0x1,
+    TOP_EDGE = 0x2,
+    LEFT_EDGE = 0x4,
+    BOTTOM_EDGE = 0x8,
+    SCREEN_CENTER = 0x0,
   };
 
+  // Given a point, if it is within the given bounds of an edge, returns the
+  // edge. If it is within the given bounds of two edges, returns an int with
+  // both bits that represent the respective edges turned on. Otherwise returns
+  // SCREEN_CENTER.
+  int WithinBoundsOfEdge(gfx::Point point, float bounds);
+
   void VlogState(const char* function_name);
 
   void VlogEvent(const ui::TouchEvent& event, const char* function_name);
@@ -254,6 +316,9 @@ class UI_CHROMEOS_EXPORT TouchExplorationController
 
   aura::Window* root_window_;
 
+  // Volume control.
+  scoped_ptr<ui::TouchExplorationControllerDelegate> delegate_;
+
   // A set of touch ids for fingers currently touching the screen.
   std::vector<int> current_touch_ids_;
 
@@ -283,6 +348,9 @@ class UI_CHROMEOS_EXPORT TouchExplorationController
   // A timer to fire the mouse move event after the double-tap delay.
   base::OneShotTimer<TouchExplorationController> tap_timer_;
 
+  // A timer to fire a indicating sound when sliding to change volume.
+  base::RepeatingTimer<TouchExplorationController> sound_timer_;
+
   // For testing only, an event handler to use for generated events
   // outside of the normal event rewriting flow.
   ui::EventHandler* event_handler_for_testing_;