Corner Passthrough for Accessibility

ui/chromeos/touch_exploration_controller.cc

Index: ui/chromeos/touch_exploration_controller.cc
diff --git a/ui/chromeos/touch_exploration_controller.cc b/ui/chromeos/touch_exploration_controller.cc
index 01e3d5424eb46c0d82cf0307999af99242e7b598..7ecb54fc0398b9e1c60bd225c47e51b921129926 100644
--- a/ui/chromeos/touch_exploration_controller.cc
+++ b/ui/chromeos/touch_exploration_controller.cc
@@ -23,6 +23,10 @@ namespace {
 // Delay between adjustment sounds.
 const base::TimeDelta kSoundDelay = base::TimeDelta::FromMilliseconds(150);
 
+// Delay before corner passthrough activates.
+const base::TimeDelta kCornerPassthroughDelay =
+    base::TimeDelta::FromMilliseconds(700);
+
 // In ChromeOS, VKEY_LWIN is synonymous for the search key.
 const ui::KeyboardCode kChromeOSSearchKey = ui::VKEY_LWIN;
 }  // namespace
@@ -35,7 +39,8 @@ TouchExplorationController::TouchExplorationController(
       state_(NO_FINGERS_DOWN),
       gesture_provider_(this),
       prev_state_(NO_FINGERS_DOWN),
-      VLOG_on_(true) {
+      VLOG_on_(true),
+      waiting_for_corner_passthrough_(false) {
   CHECK(root_window);
   root_window->GetHost()->GetEventSource()->AddEventRewriter(this);
 }
@@ -72,6 +77,13 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
     // this event under this new state.
   }
 
+  if (long_press_timer_.IsRunning() &&
+      event.time_stamp() - initial_press_->time_stamp() >
+          gesture_detector_config_.longpress_timeout) {
+    long_press_timer_.Stop();
+    OnLongPressTimerFired();
+  }
+
   const ui::EventType type = touch_event.type();
   const gfx::PointF& location = touch_event.location_f();
   const int touch_id = touch_event.touch_id();
@@ -79,14 +91,25 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
   // Always update touch ids and touch locations, so we can use those
   // no matter what state we're in.
   if (type == ui::ET_TOUCH_PRESSED) {
+    // If the user enters the screen then send an earcon.
+    gfx::Point edges = touch_event.location();
+    if (FindEdgesWithinBounds(edges, kLeavingScreenEdge) != NO_EDGE) {
+      if (VLOG_on_)
+        VLOG(0) << "Entering the screen";
+      delegate_->PlayEnterScreenEarcon();
+    }
     current_touch_ids_.push_back(touch_id);
     touch_locations_.insert(std::pair<int, gfx::PointF>(touch_id, location));
   } else if (type == ui::ET_TOUCH_RELEASED || type == ui::ET_TOUCH_CANCELLED) {
     // In order to avoid accidentally double tapping when moving off the edge of
     // the screen, the state will be rewritten to NoFingersDown.
     TouchEvent touch_event = static_cast<const TouchEvent&>(event);
-    if (FindEdgesWithinBounds(touch_event.location(), kLeavingScreenEdge) !=
-        NO_EDGE) {
+    gfx::Point edges = touch_event.location();
+    if (FindEdgesWithinBounds(edges, kLeavingScreenEdge) != NO_EDGE) {
+      if (VLOG_on_)
+        VLOG(0) << "Leaving screen";
+      // Indicates to the user that they are leaving the screen.
+      delegate_->PlayExitScreenEarcon();
       if (current_touch_ids_.size() == 0)
         ResetToNoFingersDown();
     }
@@ -131,6 +154,8 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
       return InTouchExploreSecondPress(touch_event, rewritten_event);
     case TWO_TO_ONE_FINGER:
       return InTwoToOneFinger(touch_event, rewritten_event);
+    case CORNER_PASSTHROUGH:
+      return InCornerPassthrough(touch_event, rewritten_event);
     case PASSTHROUGH:
       return InPassthrough(touch_event, rewritten_event);
     case WAIT_FOR_RELEASE:
@@ -151,29 +176,64 @@ ui::EventRewriteStatus TouchExplorationController::NextDispatchEvent(
 ui::EventRewriteStatus TouchExplorationController::InNoFingersDown(
     const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event) {
   const ui::EventType type = event.type();
-  if (type == ui::ET_TOUCH_PRESSED) {
-    initial_press_.reset(new TouchEvent(event));
-    last_unused_finger_event_.reset(new TouchEvent(event));
-    tap_timer_.Start(FROM_HERE,
-                     gesture_detector_config_.double_tap_timeout,
-                     this,
-                     &TouchExplorationController::OnTapTimerFired);
-    gesture_provider_.OnTouchEvent(event);
-    gesture_provider_.OnTouchEventAck(false);
-    ProcessGestureEvents();
-    state_ = SINGLE_TAP_PRESSED;
-    VLOG_STATE();
-    return ui::EVENT_REWRITE_DISCARD;
+  if (type != ui::ET_TOUCH_PRESSED) {
+    NOTREACHED() << "Unexpected event type received: " << event.name();
+    return ui::EVENT_REWRITE_CONTINUE;
   }
-  NOTREACHED() << "Unexpected event type received: " << event.name();;
-  return ui::EVENT_REWRITE_CONTINUE;
+  int location = FindEdgesWithinBounds(event.location(), kSlopDistanceFromEdge);
+  base::TimeDelta timeout;
+
+  // If the press was at a corner, the user might go into corner passthrough
+  // instead.
+  bool in_a_bottom_corner =
+      (BOTTOM_LEFT_CORNER == location) || (BOTTOM_RIGHT_CORNER == location);
+  if (in_a_bottom_corner) {
+    if (VLOG_on_)
+      VLOG(0) << "Location: " << location;
+    long_press_timer_.Start(FROM_HERE,
+                            gesture_detector_config_.longpress_timeout,
+                            this,
+                            &TouchExplorationController::OnLongPressTimerFired);
+    waiting_for_corner_passthrough_ = true;
+  } else {
+    waiting_for_corner_passthrough_ = false;
+  }
+  tap_timer_.Start(FROM_HERE,
+                   gesture_detector_config_.double_tap_timeout,
+                   this,
+                   &TouchExplorationController::OnTapTimerFired);
+  initial_press_.reset(new TouchEvent(event));
+  last_unused_finger_event_.reset(new TouchEvent(event));
+  gesture_provider_.OnTouchEvent(event);
+  gesture_provider_.OnTouchEventAck(false);
+  ProcessGestureEvents();
+  state_ = SINGLE_TAP_PRESSED;
+  VLOG_STATE();
+  return ui::EVENT_REWRITE_DISCARD;
 }
 
 ui::EventRewriteStatus TouchExplorationController::InSingleTapPressed(
     const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event) {
   const ui::EventType type = event.type();
 
+  int location = FindEdgesWithinBounds(event.location(), kMaxDistanceFromEdge);
+  bool in_a_bottom_corner =
+      (location == BOTTOM_LEFT_CORNER) || (location == BOTTOM_RIGHT_CORNER);
+  // If the event is from the initial press and the location is no longer in the
+  // corner, then we are not waiting for a corner passthrough anymore.
+  if (event.touch_id() == initial_press_->touch_id() && !in_a_bottom_corner) {
+    waiting_for_corner_passthrough_ = false;
+    if (long_press_timer_.IsRunning()) {
+      long_press_timer_.Stop();
+      if (event.time_stamp() - initial_press_->time_stamp() >
+          gesture_detector_config_.double_tap_timeout) {
+        OnTapTimerFired();
+      }
+    }
+  }
+
   if (type == ui::ET_TOUCH_PRESSED) {
+    waiting_for_corner_passthrough_ = false;
     // Adding a second finger within the timeout period switches to
     // passing through every event from the second finger and none form the
     // first. The event from the first finger is still saved in initial_press_.
@@ -186,6 +246,7 @@ ui::EventRewriteStatus TouchExplorationController::InSingleTapPressed(
     (*rewritten_event)->set_flags(event.flags());
     return EVENT_REWRITE_REWRITTEN;
   } else if (type == ui::ET_TOUCH_RELEASED || type == ui::ET_TOUCH_CANCELLED) {
+    waiting_for_corner_passthrough_ = false;
     DCHECK_EQ(0U, current_touch_ids_.size());
     state_ = SINGLE_TAP_RELEASED;
     VLOG_STATE();
@@ -201,15 +262,15 @@ ui::EventRewriteStatus TouchExplorationController::InSingleTapPressed(
     float delta_time =
         (event.time_stamp() - initial_press_->time_stamp()).InSecondsF();
     float velocity = distance / delta_time;
-    VLOG(0) << "\n Delta time: " << delta_time
-            << "\n Distance: " << distance
-            << "\n Velocity of click: " << velocity
-            << "\n Minimum swipe velocity: "
-            << gesture_detector_config_.minimum_swipe_velocity;
-
+    if (VLOG_on_) {
+      VLOG(0) << "\n Delta time: " << delta_time << "\n Distance: " << distance
+              << "\n Velocity of click: " << velocity
+              << "\n Minimum swipe velocity: "
+              << gesture_detector_config_.minimum_swipe_velocity;
+    }
     // Change to slide gesture if the slide occurred at the right edge.
     int edge = FindEdgesWithinBounds(event.location(), kMaxDistanceFromEdge);
-    if (edge & RIGHT_EDGE) {
+    if (edge & RIGHT_EDGE && edge != BOTTOM_RIGHT_CORNER) {
       state_ = SLIDE_GESTURE;
       VLOG_STATE();
       return InSlideGesture(event, rewritten_event);
@@ -398,7 +459,7 @@ ui::EventRewriteStatus TouchExplorationController::InTwoToOneFinger(
     // If a third finger is pressed, we are now going into passthrough mode
     // and now need to dispatch the first finger into a press, as well as the
     // recent press.
-    if (current_touch_ids_.size() == 3){
+    if (current_touch_ids_.size() == 3) {
       state_ = PASSTHROUGH;
       scoped_ptr<ui::TouchEvent> first_finger_press;
       first_finger_press.reset(
@@ -437,6 +498,40 @@ ui::EventRewriteStatus TouchExplorationController::InTwoToOneFinger(
   return ui::EVENT_REWRITE_CONTINUE;
 }
 
+ui::EventRewriteStatus TouchExplorationController::InCornerPassthrough(
+    const ui::TouchEvent& event,
+    scoped_ptr<ui::Event>* rewritten_event) {
+  ui::EventType type = event.type();
+
+  // If the first finger has left the corner, then exit passthrough.
+  if (event.touch_id() == initial_press_->touch_id()) {
+    int edges = FindEdgesWithinBounds(event.location(), kSlopDistanceFromEdge);
+    bool in_a_bottom_corner = (edges == BOTTOM_LEFT_CORNER) ||
+                              (edges == BOTTOM_RIGHT_CORNER);
+    if (type == ui::ET_TOUCH_MOVED && in_a_bottom_corner)
+      return ui::EVENT_REWRITE_DISCARD;
+
+    if (current_touch_ids_.size() == 0) {
+      ResetToNoFingersDown();
+      return ui::EVENT_REWRITE_DISCARD;
+    }
+
+    waiting_for_corner_passthrough_ = false;
+    state_ = WAIT_FOR_RELEASE;
+    VLOG_STATE();
+    return ui::EVENT_REWRITE_DISCARD;
+  }
+
+  rewritten_event->reset(new ui::TouchEvent(
+      type, event.location(), event.touch_id(), event.time_stamp()));
+  (*rewritten_event)->set_flags(event.flags());
+
+  if (current_touch_ids_.size() == 0)
+    ResetToNoFingersDown();
+
+  return ui::EVENT_REWRITE_REWRITTEN;
+}
+
 ui::EventRewriteStatus TouchExplorationController::InPassthrough(
     const ui::TouchEvent& event,
     scoped_ptr<ui::Event>* rewritten_event) {
@@ -504,6 +599,7 @@ ui::EventRewriteStatus TouchExplorationController::InTouchExploreSecondPress(
 ui::EventRewriteStatus TouchExplorationController::InWaitForRelease(
     const ui::TouchEvent& event,
     scoped_ptr<ui::Event>* rewritten_event) {
+  waiting_for_corner_passthrough_ = false;
   ui::EventType type = event.type();
   if (!(type == ui::ET_TOUCH_PRESSED || type == ui::ET_TOUCH_MOVED ||
         type == ui::ET_TOUCH_RELEASED || type == ui::ET_TOUCH_CANCELLED)) {
@@ -519,7 +615,7 @@ ui::EventRewriteStatus TouchExplorationController::InWaitForRelease(
 }
 
 void TouchExplorationController::PlaySoundForTimer() {
-  delegate_->PlayVolumeAdjustSound();
+  delegate_->PlayVolumeAdjustEarcon();
 }
 
 ui::EventRewriteStatus TouchExplorationController::InSlideGesture(
@@ -559,7 +655,7 @@ ui::EventRewriteStatus TouchExplorationController::InSlideGesture(
                        kSoundDelay,
                        this,
                        &ui::TouchExplorationController::PlaySoundForTimer);
-    delegate_->PlayVolumeAdjustSound();
+    delegate_->PlayVolumeAdjustEarcon();
   }
 
   // There should not be more than one finger down.
@@ -591,6 +687,8 @@ void TouchExplorationController::OnTapTimerFired() {
       last_touch_exploration_.reset(new TouchEvent(*initial_press_));
       return;
     case SINGLE_TAP_PRESSED:
+      if (waiting_for_corner_passthrough_)
+        return;
     case GESTURE_IN_PROGRESS:
       // Discard any pending gestures.
       delete gesture_provider_.GetAndResetPendingGestures();
@@ -607,6 +705,18 @@ void TouchExplorationController::OnTapTimerFired() {
   last_touch_exploration_.reset(new TouchEvent(*initial_press_));
 }
 
+void TouchExplorationController::OnLongPressTimerFired() {
+  if (waiting_for_corner_passthrough_) {
+    if (sound_timer_.IsRunning())
+      sound_timer_.Stop();
+    delegate_->PlayPassthroughEarcon();
+    delete gesture_provider_.GetAndResetPendingGestures();
+    state_ = CORNER_PASSTHROUGH;
+    VLOG_STATE();
+    return;
+  }
+}
+
 void TouchExplorationController::DispatchEvent(ui::Event* event) {
   ui::EventDispatchDetails result ALLOW_UNUSED =
       root_window_->GetHost()->dispatcher()->OnEventFromSource(event);
@@ -646,13 +756,13 @@ void TouchExplorationController::SideSlideControl(ui::GestureEvent* gesture) {
     return;
 
   if (type == ET_GESTURE_SCROLL_BEGIN) {
-    delegate_->PlayVolumeAdjustSound();
+    delegate_->PlayVolumeAdjustEarcon();
   }
 
   if (type == ET_GESTURE_SCROLL_END) {
     if (sound_timer_.IsRunning())
       sound_timer_.Stop();
-    delegate_->PlayVolumeAdjustSound();
+    delegate_->PlayVolumeAdjustEarcon();
   }
 
   // If the user is in the corner of the right side of the screen, the volume
@@ -680,9 +790,11 @@ void TouchExplorationController::SideSlideControl(ui::GestureEvent* gesture) {
       root_window_->bounds().height() - 2 * kMaxDistanceFromEdge;
   float ratio = (location.y() - kMaxDistanceFromEdge) / volume_adjust_height;
   float volume = 100 - 100 * ratio;
-  VLOG(0) << "\n Volume = " << volume << "\n Location = " << location.ToString()
-          << "\n Bounds = " << root_window_->bounds().right();
-
+  if (VLOG_on_) {
+    VLOG(0) << "\n Volume = " << volume
+            << "\n Location = " << location.ToString()
+            << "\n Bounds = " << root_window_->bounds().right();
+  }
   delegate_->SetOutputLevel(int(volume));
 }
 
@@ -797,6 +909,7 @@ void TouchExplorationController::EnterTouchToMouseMode() {
 }
 
 void TouchExplorationController::ResetToNoFingersDown() {
+  waiting_for_corner_passthrough_ = false;
   ProcessGestureEvents();
   if (sound_timer_.IsRunning())
     sound_timer_.Stop();
@@ -867,6 +980,8 @@ const char* TouchExplorationController::EnumStateToString(State state) {
       return "TOUCH_EXPLORE_SECOND_PRESS";
     case TWO_TO_ONE_FINGER:
       return "TWO_TO_ONE_FINGER";
+    case CORNER_PASSTHROUGH:
+      return "CORNER_PASSTHROUGH";
     case PASSTHROUGH:
       return "PASSTHROUGH";
     case WAIT_FOR_RELEASE: