Add two finger tap gesture to gesture recognizer.

BUG=126058
TEST=none

Review URL: https://chromiumcodereview.appspot.com/10447129

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@140553 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 147 insertions, 8 deletions

diff --git a/ui/base/gestures/gesture_configuration.cc b/ui/base/gestures/gesture_configuration.cc
index 5752144..b83a64a 100644
--- a/ui/base/gestures/gesture_configuration.cc
+++ b/ui/base/gestures/gesture_configuration.cc
@@ -10,6 +10,7 @@ namespace ui {
 // associated list of prefs in gesture_prefs_aura.cc.
 int GestureConfiguration::default_radius_ = 15;
 double GestureConfiguration::long_press_time_in_seconds_ = 1.0;
+double GestureConfiguration::max_distance_for_two_finger_tap_in_pixels_ = 300;
 int GestureConfiguration::max_radius_ = 100;
 double GestureConfiguration::max_seconds_between_double_click_ = 0.7;
 double
diff --git a/ui/base/gestures/gesture_configuration.h b/ui/base/gestures/gesture_configuration.h
index f491ccd..397dbc6 100644
--- a/ui/base/gestures/gesture_configuration.h
+++ b/ui/base/gestures/gesture_configuration.h
@@ -25,6 +25,12 @@ class UI_EXPORT GestureConfiguration {
   static double long_press_time_in_seconds() {
     return long_press_time_in_seconds_;
   }
+  static double max_distance_for_two_finger_tap_in_pixels() {
+    return max_distance_for_two_finger_tap_in_pixels_;
+  }
+  static void set_max_distance_for_two_finger_tap_in_pixels(double val) {
+    max_distance_for_two_finger_tap_in_pixels_ = val;
+  }
   static int max_radius() {
     return max_radius_;
   }
@@ -131,6 +137,11 @@ class UI_EXPORT GestureConfiguration {
   // by the device is the touch center.
   static int default_radius_;
 
+  // The maximum allowed distance between two fingers for a two finger tap. If
+  // the distance between two fingers is greater than this value, we will not
+  // recognize a two finger tap.
+  static double max_distance_for_two_finger_tap_in_pixels_;
+
   // The maximum allowed size for the radius of a touch region used in
   // forming an ET_GESTURE_TAP event.
   static int max_radius_;
diff --git a/ui/base/gestures/gesture_point.h b/ui/base/gestures/gesture_point.h
index 19a8a3c..d019892 100644
--- a/ui/base/gestures/gesture_point.h
+++ b/ui/base/gestures/gesture_point.h
@@ -44,6 +44,7 @@ class GesturePoint {
   bool IsInFlickWindow(const TouchEvent& event);
   bool IsInHorizontalRailWindow() const;
   bool IsInVerticalRailWindow() const;
+  bool IsInsideManhattanSquare(const TouchEvent& event) const;
   bool HasEnoughDataToEstablishRail() const;
   bool BreaksHorizontalRail();
   bool BreaksVerticalRail();
@@ -89,7 +90,6 @@ class GesturePoint {
   // Various statistical functions to manipulate gestures.
   bool IsInClickTimeWindow() const;
   bool IsInSecondClickTimeWindow() const;
-  bool IsInsideManhattanSquare(const TouchEvent& event) const;
   bool IsSecondClickInsideManhattanSquare(const TouchEvent& event) const;
   bool IsOverMinFlickSpeed();
 
diff --git a/ui/base/gestures/gesture_sequence.cc b/ui/base/gestures/gesture_sequence.cc
index c0441fe..f11d5d1 100644
--- a/ui/base/gestures/gesture_sequence.cc
+++ b/ui/base/gestures/gesture_sequence.cc
@@ -88,6 +88,27 @@ enum EdgeStateSignatureType {
   GST_SCROLL_SECOND_PRESSED =
       G(GS_SCROLL, 1, TS_PRESSED, false),
 
+  GST_PENDING_TWO_FINGER_TAP_FIRST_RELEASED =
+      G(GS_PENDING_TWO_FINGER_TAP, 0, TS_RELEASED, false),
+
+  GST_PENDING_TWO_FINGER_TAP_SECOND_RELEASED =
+      G(GS_PENDING_TWO_FINGER_TAP, 1, TS_RELEASED, false),
+
+  GST_PENDING_TWO_FINGER_TAP_FIRST_MOVED =
+      G(GS_PENDING_TWO_FINGER_TAP, 0, TS_MOVED, false),
+
+  GST_PENDING_TWO_FINGER_TAP_SECOND_MOVED =
+      G(GS_PENDING_TWO_FINGER_TAP, 1, TS_MOVED, false),
+
+  GST_PENDING_TWO_FINGER_TAP_FIRST_CANCELLED =
+      G(GS_PENDING_TWO_FINGER_TAP, 0, TS_CANCELLED, false),
+
+  GST_PENDING_TWO_FINGER_TAP_SECOND_CANCELLED =
+      G(GS_PENDING_TWO_FINGER_TAP, 1, TS_CANCELLED, false),
+
+  GST_PENDING_TWO_FINGER_TAP_THIRD_PRESSED =
+      G(GS_PENDING_TWO_FINGER_TAP, 2, TS_PRESSED, false),
+
   GST_PINCH_FIRST_MOVED =
       G(GS_PINCH, 0, TS_MOVED, false),
 
@@ -262,8 +283,30 @@ GestureSequence::Gestures* GestureSequence::ProcessTouchEventForGesture(
       break;
     case GST_SCROLL_SECOND_PRESSED:
     case GST_PENDING_SYNTHETIC_CLICK_SECOND_PRESSED:
-      // Once pinch starts, we immediately break rail scroll.
+      if (IsSecondTouchDownCloseEnoughForTwoFingerTap()) {
+        TwoFingerTouchDown(event, point, gestures.get());
+        set_state(GS_PENDING_TWO_FINGER_TAP);
+      } else {
+        PinchStart(event, point, gestures.get());
+        set_state(GS_PINCH);
+      }
+      break;
+    case GST_PENDING_TWO_FINGER_TAP_FIRST_RELEASED:
+    case GST_PENDING_TWO_FINGER_TAP_SECOND_RELEASED:
+      TwoFingerTouchReleased(event, point, gestures.get());
+      set_state(GS_SCROLL);
+      break;
+    case GST_PENDING_TWO_FINGER_TAP_FIRST_MOVED:
+    case GST_PENDING_TWO_FINGER_TAP_SECOND_MOVED:
+      if (TwoFingerTouchMove(event, point, gestures.get()))
+        set_state(GS_PINCH);
+      break;
+    case GST_PENDING_TWO_FINGER_TAP_FIRST_CANCELLED:
+    case GST_PENDING_TWO_FINGER_TAP_SECOND_CANCELLED:
       scroll_type_ = ST_FREE;
+      set_state(GS_SCROLL);
+      break;
+    case GST_PENDING_TWO_FINGER_TAP_THIRD_PRESSED:
       PinchStart(event, point, gestures.get());
       set_state(GS_PINCH);
       break;
@@ -414,6 +457,18 @@ GesturePoint* GestureSequence::GetPointByPointId(int point_id) {
   return NULL;
 }
 
+bool GestureSequence::IsSecondTouchDownCloseEnoughForTwoFingerTap() {
+  gfx::Point p1 = GetPointByPointId(0)->last_touch_position();
+  gfx::Point p2 = GetPointByPointId(1)->last_touch_position();
+  double max_distance =
+      ui::GestureConfiguration::max_distance_for_two_finger_tap_in_pixels();
+  double distance = (p1.x() - p2.x()) * (p1.x() - p2.x()) +
+      (p1.y() - p2.y()) * (p1.y() - p2.y());
+  if (distance < max_distance * max_distance)
+    return true;
+  return false;
+}
+
 void GestureSequence::AppendTapDownGestureEvent(const GesturePoint& point,
                                                 Gestures* gestures) {
   gestures->push_back(helper_->CreateGestureEvent(
@@ -581,6 +636,16 @@ void GestureSequence::AppendSwipeGesture(const GesturePoint& point,
       swipe_x, swipe_y, ComputeTouchBitmask(points_)));
 }
 
+void GestureSequence::AppendTwoFingerTapGestureEvent(Gestures* gestures) {
+  const GesturePoint* point = GetPointByPointId(0);
+  gestures->push_back(helper_->CreateGestureEvent(
+      ui::ET_GESTURE_TWO_FINGER_TAP,
+      point->enclosing_rectangle().CenterPoint(),
+      flags_,
+      base::Time::FromDoubleT(point->last_touch_time()),
+      0.f, 0.f, 1 << point->touch_id()));
+}
+
 bool GestureSequence::Click(const TouchEvent& event,
     const GesturePoint& point, Gestures* gestures) {
   DCHECK(state_ == GS_PENDING_SYNTHETIC_CLICK);
@@ -649,6 +714,42 @@ bool GestureSequence::TouchDown(const TouchEvent& event,
   return true;
 }
 
+bool GestureSequence::TwoFingerTouchDown(const TouchEvent& event,
+    const GesturePoint& point, Gestures* gestures) {
+  DCHECK(state_ == GS_PENDING_SYNTHETIC_CLICK || state_ == GS_SCROLL);
+  if (state_ == GS_SCROLL) {
+    AppendScrollGestureEnd(point, point.last_touch_position(), gestures,
+        0.f, 0.f);
+  }
+  second_touch_time_ = event.GetTimestamp();
+  return true;
+}
+
+bool GestureSequence::TwoFingerTouchMove(const TouchEvent& event,
+    const GesturePoint& point, Gestures* gestures) {
+  DCHECK(state_ == GS_PENDING_TWO_FINGER_TAP);
+
+  base::TimeDelta time_delta = event.GetTimestamp() - second_touch_time_;
+  base::TimeDelta max_delta = base::TimeDelta::FromMilliseconds(1000 *
+      ui::GestureConfiguration::max_touch_down_duration_in_seconds_for_click());
+  if (time_delta > max_delta || !point.IsInsideManhattanSquare(event)) {
+    PinchStart(event, point, gestures);
+    return true;
+  }
+  return false;
+}
+
+bool GestureSequence::TwoFingerTouchReleased(const TouchEvent& event,
+    const GesturePoint& point, Gestures* gestures) {
+  DCHECK(state_ == GS_PENDING_TWO_FINGER_TAP);
+  base::TimeDelta time_delta = event.GetTimestamp() - second_touch_time_;
+  base::TimeDelta max_delta = base::TimeDelta::FromMilliseconds(1000 *
+      ui::GestureConfiguration::max_touch_down_duration_in_seconds_for_click());
+  if (time_delta < max_delta && point.IsInsideManhattanSquare(event))
+    AppendTwoFingerTapGestureEvent(gestures);
+  return true;
+}
+
 void GestureSequence::AppendLongPressGestureEvent() {
   const GesturePoint* point = GetPointByPointId(0);
   scoped_ptr<GestureEvent> gesture(helper_->CreateGestureEvent(
@@ -676,8 +777,11 @@ bool GestureSequence::ScrollEnd(const TouchEvent& event,
 bool GestureSequence::PinchStart(const TouchEvent& event,
     const GesturePoint& point, Gestures* gestures) {
   DCHECK(state_ == GS_SCROLL ||
-         state_ == GS_PENDING_SYNTHETIC_CLICK);
-  AppendTapDownGestureEvent(point, gestures);
+         state_ == GS_PENDING_SYNTHETIC_CLICK ||
+         state_ == GS_PENDING_TWO_FINGER_TAP);
+
+  // Once pinch starts, we immediately break rail scroll.
+  scroll_type_ = ST_FREE;
 
   const GesturePoint* point1 = GetPointByPointId(0);
   const GesturePoint* point2 = GetPointByPointId(1);
@@ -686,7 +790,8 @@ bool GestureSequence::PinchStart(const TouchEvent& event,
   pinch_distance_start_ = pinch_distance_current_;
   AppendPinchGestureBegin(*point1, *point2, gestures);
 
-  if (state_ == GS_PENDING_SYNTHETIC_CLICK) {
+  if (state_ == GS_PENDING_SYNTHETIC_CLICK ||
+      state_ == GS_PENDING_TWO_FINGER_TAP) {
     gfx::Point center = bounding_box_.CenterPoint();
     AppendScrollGestureBegin(point, center, gestures);
   }
diff --git a/ui/base/gestures/gesture_sequence.h b/ui/base/gestures/gesture_sequence.h
index 0a52578..b976bb3 100644
--- a/ui/base/gestures/gesture_sequence.h
+++ b/ui/base/gestures/gesture_sequence.h
@@ -22,6 +22,7 @@ enum GestureState {
   GS_PENDING_SYNTHETIC_CLICK,
   GS_SCROLL,
   GS_PINCH,
+  GS_PENDING_TWO_FINGER_TAP,
 };
 
 enum ScrollType {
@@ -71,6 +72,8 @@ class UI_EXPORT GestureSequence {
   // with id |point_id|.
   GesturePoint* GetPointByPointId(int point_id);
 
+  bool IsSecondTouchDownCloseEnoughForTwoFingerTap();
+
   // Functions to be called to add GestureEvents, after successful recognition.
 
   // Tap gestures.
@@ -109,6 +112,7 @@ class UI_EXPORT GestureSequence {
                           int swipe_x,
                           int swipe_y,
                           Gestures* gestures);
+  void AppendTwoFingerTapGestureEvent(Gestures* gestures);
 
   void set_state(const GestureState state) { state_ = state; }
 
@@ -133,6 +137,15 @@ class UI_EXPORT GestureSequence {
   bool TouchDown(const TouchEvent& event,
                  const GesturePoint& point,
                  Gestures* gestures);
+  bool TwoFingerTouchDown(const TouchEvent& event,
+                          const GesturePoint& point,
+                          Gestures* gestures);
+  bool TwoFingerTouchMove(const TouchEvent& event,
+                          const GesturePoint& point,
+                          Gestures* gestures);
+  bool TwoFingerTouchReleased(const TouchEvent& event,
+                              const GesturePoint& point,
+                              Gestures* gestures);
   bool ScrollEnd(const TouchEvent& event,
                  GesturePoint& point,
                  Gestures* gestures);
@@ -170,6 +183,10 @@ class UI_EXPORT GestureSequence {
   // This distance is updated after each PINCH_UPDATE.
   float pinch_distance_current_;
 
+  // This is the time when second touch down was received. Used for determining
+  // if a two finger double tap has happened.
+  base::TimeDelta second_touch_time_;
+
   ScrollType scroll_type_;
   scoped_ptr<base::OneShotTimer<GestureSequence> > long_press_timer_;
 
diff --git a/ui/base/gestures/gestures.dot b/ui/base/gestures/gestures.dot
index 6e3aa5c..868c542 100644
--- a/ui/base/gestures/gestures.dot
+++ b/ui/base/gestures/gestures.dot
@@ -13,7 +13,8 @@ M : Move          \l\
 D : Down          \l\
 S : Stationary    \l\
 C : Cancel        \l\
-R : Release       \l}"  
+R : Release       \l\
+M_Delay : Move after a certain delay}"
 shape = record]
 
 subgraph none_pending {
@@ -25,8 +26,12 @@ GS_PENDING_SYNTHETIC_CLICK ->  GS_NO_GESTURE [label= "C0\n R0"];
 
 GS_SCROLL ->  GS_SCROLL [label= "M0"];
 GS_SCROLL ->  GS_NO_GESTURE [label= "C0\n R0\n"];
-GS_PENDING_SYNTHETIC_CLICK ->  GS_PINCH [label= "D1"];
-GS_SCROLL ->  GS_PINCH [label= "D1"];
+GS_PENDING_SYNTHETIC_CLICK ->  GS_PENDING_TWO_FINGER_TAP [label= "D1"];
+GS_SCROLL ->  GS_PENDING_TWO_FINGER_TAP [label= "D1"];
+GS_PENDING_TWO_FINGER_TAP -> GS_PINCH [label= "M0\n M1"];
+GS_PENDING_TWO_FINGER_TAP -> GS_PINCH [label= "M_Delay0\n M_Delay1"];
+GS_PENDING_TWO_FINGER_TAP -> GS_PINCH [label= "D2"];
+GS_PENDING_TWO_FINGER_TAP -> GS_SCROLL [label= "R0\n R1\n C0\n C1"];
 GS_PINCH ->  GS_PINCH [label= "M0\n M1"];
 GS_PINCH ->  GS_SCROLL [label= "C0\n R0\n C1\n R1"];