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 3670f1e948f213908d1884d9f844eacf35916a5c..4b31d4c56bc87843274c8aff8e7bd250a44f2311 100644
--- a/ui/chromeos/touch_exploration_controller.cc
+++ b/ui/chromeos/touch_exploration_controller.cc
@@ -25,6 +25,10 @@ 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
@@ -68,6 +72,13 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
     // this event under this new state.
   }
 
+  if (passthrough_timer_.IsRunning() &&
+      event.time_stamp() - initial_press_->time_stamp() >
+          gesture_detector_config_.longpress_timeout) {
+    passthrough_timer_.Stop();
+    OnPassthroughTimerFired();
+  }
+
   const ui::EventType type = touch_event.type();
   const gfx::PointF& location = touch_event.location_f();
   const int touch_id = touch_event.touch_id();
@@ -81,11 +92,14 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
     // 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) {
-      if (current_touch_ids_.size() == 0) {
-        ResetToNoFingersDown();
-      }
+    gfx::Point edges = touch_event.location();
+    if (FindEdgesWithinBounds(edges, kLeavingScreenEdge) != NO_EDGE) {
+        // Indicates to the user that they are leaving the screen.
+      if (VLOG_on_)
+        VLOG(0) << "Leaving the Screen";
+      delegate_->PlayExitScreenEarcon();
+      if (current_touch_ids_.size() == 0)
+          ResetToNoFingersDown();
     }
 
     std::vector<int>::iterator it = std::find(
@@ -128,6 +142,8 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
       return InGestureInProgress(touch_event, rewritten_event);
     case TOUCH_EXPLORE_SECOND_PRESS:
       return InTouchExploreSecondPress(touch_event, rewritten_event);
+    case CORNER_PASSTHROUGH:
+      return InCornerPassthrough(touch_event, rewritten_event);
     case SLIDE_GESTURE:
       return InSlideGesture(touch_event, rewritten_event);
     case ONE_FINGER_PASSTHROUGH:
@@ -148,25 +164,65 @@ 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));
-    StartTapTimer();
-    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;
+
+  // If the user enters the screen from the edge then send an earcon.
+  int edge = FindEdgesWithinBounds(event.location(), kLeavingScreenEdge);
+  if (edge != NO_EDGE)
+    delegate_->PlayEnterScreenEarcon();
+
+  int location = FindEdgesWithinBounds(event.location(), kSlopDistanceFromEdge);
+  // 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) {
+    passthrough_timer_.Start(
+        FROM_HERE,
+        gesture_detector_config_.longpress_timeout,
+        this,
+        &TouchExplorationController::OnPassthroughTimerFired);
+  }
+
+  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) {
+    if (passthrough_timer_.IsRunning()) {
+      passthrough_timer_.Stop();
+      // Since the long press timer has been running, it is possible that the
+      // tap timer has timed out before the long press timer has. If the tap
+      // timer timeout has elapsed, then fire the tap timer.
+      if (event.time_stamp() - initial_press_->time_stamp() >
+          gesture_detector_config_.double_tap_timeout) {
+        OnTapTimerFired();
+      }
+    }
+  }
+
   if (type == ui::ET_TOUCH_PRESSED) {
     // TODO (evy, lisayin) : add support for multifinger swipes.
     // For now, we wait for there to be only one finger down again.
@@ -200,7 +256,7 @@ ui::EventRewriteStatus TouchExplorationController::InSingleTapPressed(
     }
     // 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);
@@ -393,6 +449,39 @@ ui::EventRewriteStatus TouchExplorationController::InGestureInProgress(
   return ui::EVENT_REWRITE_DISCARD;
 }
 
+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;
+    }
+
+    state_ = WAIT_FOR_ONE_FINGER;
+    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::InOneFingerPassthrough(
     const ui::TouchEvent& event,
     scoped_ptr<ui::Event>* rewritten_event) {
@@ -486,7 +575,7 @@ ui::EventRewriteStatus TouchExplorationController::InWaitForOneFinger(
 }
 
 void TouchExplorationController::PlaySoundForTimer() {
-  delegate_->PlayVolumeAdjustSound();
+  delegate_->PlayVolumeAdjustEarcon();
 }
 
 ui::EventRewriteStatus TouchExplorationController::InSlideGesture(
@@ -526,7 +615,7 @@ ui::EventRewriteStatus TouchExplorationController::InSlideGesture(
                        kSoundDelay,
                        this,
                        &ui::TouchExplorationController::PlaySoundForTimer);
-    delegate_->PlayVolumeAdjustSound();
+    delegate_->PlayVolumeAdjustEarcon();
   }
 
   // There should not be more than one finger down.
@@ -589,6 +678,8 @@ void TouchExplorationController::OnTapTimerFired() {
       return;
     }
     case SINGLE_TAP_PRESSED:
+      if (passthrough_timer_.IsRunning())
+        return;
     case GESTURE_IN_PROGRESS:
       // Discard any pending gestures.
       delete gesture_provider_.GetAndResetPendingGestures();
@@ -605,6 +696,32 @@ void TouchExplorationController::OnTapTimerFired() {
   last_touch_exploration_.reset(new TouchEvent(*initial_press_));
 }
 
+void TouchExplorationController::OnPassthroughTimerFired() {
+  // The long press timer should only be running if one finger is in the corner

[aboxhall, 2014/08/06 21:03:12]

I see why this comment was added, but I think it's a little confusing out of
context since you're not checking for the stated condition - perhaps reword as
"The long press timer will only fire if the user has held a finger in one of the
passthrough corners for the duration of the passthrough timeout" or similar.

[lisayin, 2014/08/06 21:48:23]

Done.

+  // ready for corner passthrough
+
+  // Check that initial press isn't null and that the id of the initial press
+  // still exists in touch_locations_.
+  if (!initial_press_ ||
+      touch_locations_.end() ==
+      touch_locations_.find(initial_press_->touch_id()))
+    return;

[aboxhall, 2014/08/06 21:03:12]

Is this an error/shouldn't happen condition? Also, nit: use {} since your
condition goes over more than one line.

[lisayin, 2014/08/06 21:48:22]

Done.

+
+  gfx::Point location =
+      ToRoundedPoint(touch_locations_[initial_press_->touch_id()]);
+  int corner = FindEdgesWithinBounds(location, kSlopDistanceFromEdge);
+  if (corner != BOTTOM_LEFT_CORNER && corner != BOTTOM_RIGHT_CORNER)
+    return;
+
+  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 +763,13 @@ 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
@@ -799,13 +916,16 @@ void TouchExplorationController::EnterTouchToMouseMode() {
 }
 
 void TouchExplorationController::ResetToNoFingersDown() {
-  ProcessGestureEvents();
+  if (passthrough_timer_.IsRunning())

[aboxhall, 2014/08/06 21:03:12]

Note that in each of these cases, the IsRunning() check is redundant (I should
have picked that up much earlier, sorry).

[lisayin, 2014/08/06 21:48:23]

Done.

+    passthrough_timer_.Stop();
   if (sound_timer_.IsRunning())
     sound_timer_.Stop();
-  state_ = NO_FINGERS_DOWN;
-  VLOG_STATE();
   if (tap_timer_.IsRunning())
     tap_timer_.Stop();
+  ProcessGestureEvents();
+  state_ = NO_FINGERS_DOWN;
+  VLOG_STATE();
+
 }
 
 void TouchExplorationController::VlogState(const char* function_name) {
@@ -869,6 +989,8 @@ const char* TouchExplorationController::EnumStateToString(State state) {
       return "GESTURE_IN_PROGRESS";
     case TOUCH_EXPLORE_SECOND_PRESS:
       return "TOUCH_EXPLORE_SECOND_PRESS";
+    case CORNER_PASSTHROUGH:
+      return "CORNER_PASSTHROUGH";
     case SLIDE_GESTURE:
       return "SLIDE_GESTURE";
     case ONE_FINGER_PASSTHROUGH: