Added multi-finger gestures to touch_exploration_controller

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 6b2584afc7f2afc4c3d6bec3c3491e1fb11ae054..40f9d385b4af4a035cc83124b52e2e038f081ee6 100644
--- a/ui/chromeos/touch_exploration_controller.cc
+++ b/ui/chromeos/touch_exploration_controller.cc
@@ -6,6 +6,7 @@
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/time/default_tick_clock.h"
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
@@ -39,6 +40,7 @@ TouchExplorationController::TouchExplorationController(
       gesture_provider_(this),
       prev_state_(NO_FINGERS_DOWN),
       VLOG_on_(true),
+      send_gesture_events_(false),
       tick_clock_(NULL) {
   CHECK(root_window);
   root_window->GetHost()->GetEventSource()->AddEventRewriter(this);
@@ -52,6 +54,13 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
     const ui::Event& event,
     scoped_ptr<ui::Event>* rewritten_event) {
   if (!event.IsTouchEvent()) {
+    if (event.IsKeyEvent()) {
+      const ui::KeyEvent& key_event = static_cast<const ui::KeyEvent&>(event);
+      VLOG(0) << "\nKeyboard event: " << key_event.name()
+              << "\n Key code: " << key_event.key_code()
+              << ", Flags: " << key_event.flags()
+              << ", Is char: " << key_event.is_char();
+    }
     return ui::EVENT_REWRITE_CONTINUE;
   }
   const ui::TouchEvent& touch_event = static_cast<const ui::TouchEvent&>(event);
@@ -69,6 +78,14 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
     // this event under this new state.
   }
 
+  // If a gesture has ended, we need to keep proccessing touch events so that
+  // the gesture provider can keep track of how many fingers are down.
+  if (send_gesture_events_) {
+    gesture_provider_.OnTouchEvent(touch_event);
+    gesture_provider_.OnTouchEventAck(false);
+    delete gesture_provider_.GetAndResetPendingGestures();
+  }
+
   const ui::EventType type = touch_event.type();
   const gfx::PointF& location = touch_event.location_f();
   const int touch_id = touch_event.touch_id();
@@ -79,8 +96,8 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
     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.
+    // 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) {
@@ -111,7 +128,7 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
   VLOG_STATE();
   VLOG_EVENT(touch_event);
   // The rest of the processing depends on what state we're in.
-  switch(state_) {
+  switch (state_) {
     case NO_FINGERS_DOWN:
       return InNoFingersDown(touch_event, rewritten_event);
     case SINGLE_TAP_PRESSED:
@@ -129,12 +146,12 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
       return InGestureInProgress(touch_event, rewritten_event);
     case TOUCH_EXPLORE_SECOND_PRESS:
       return InTouchExploreSecondPress(touch_event, rewritten_event);
-    case SLIDE_GESTURE:
-      return InSlideGesture(touch_event, rewritten_event);
     case ONE_FINGER_PASSTHROUGH:
       return InOneFingerPassthrough(touch_event, rewritten_event);
     case WAIT_FOR_ONE_FINGER:
       return InWaitForOneFinger(touch_event, rewritten_event);
+    case SLIDE_GESTURE:
+      return InSlideGesture(touch_event, rewritten_event);
   }
   NOTREACHED();
   return ui::EVENT_REWRITE_CONTINUE;
@@ -169,10 +186,10 @@ ui::EventRewriteStatus TouchExplorationController::InSingleTapPressed(
   const ui::EventType type = event.type();
 
   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.
-    state_ = WAIT_FOR_ONE_FINGER;
-    return EVENT_REWRITE_DISCARD;
+    // This is the start of a multifinger gesture.
+    state_ = GESTURE_IN_PROGRESS;
+    VLOG_STATE();
+    return InGestureInProgress(event, rewritten_event);
   } else if (type == ui::ET_TOUCH_RELEASED || type == ui::ET_TOUCH_CANCELLED) {
     if (current_touch_ids_.size() == 0 &&
         event.touch_id() == initial_press_->touch_id()) {
@@ -232,6 +249,7 @@ TouchExplorationController::InSingleTapOrTouchExploreReleased(
   // finger is or no fingers are down.
   if (current_touch_ids_.size() > 1) {
     state_ = WAIT_FOR_ONE_FINGER;
+    VLOG_STATE();
     return ui::EVENT_REWRITE_DISCARD;
   }
   if (type == ui::ET_TOUCH_PRESSED) {
@@ -365,30 +383,18 @@ ui::EventRewriteStatus TouchExplorationController::InGestureInProgress(
     const ui::TouchEvent& event,
     scoped_ptr<ui::Event>* rewritten_event) {
   ui::EventType type = event.type();
-  // If additional fingers are added before a swipe gesture has been
-  // registered, then the state will no longer be GESTURE_IN_PROGRESS.
-  if (type == ui::ET_TOUCH_PRESSED ||
-      event.touch_id() != initial_press_->touch_id()) {
-    if (tap_timer_.IsRunning())
-      tap_timer_.Stop();
-    // Discard any pending gestures.
-    delete gesture_provider_.GetAndResetPendingGestures();
-    state_ = WAIT_FOR_ONE_FINGER;
-    return EVENT_REWRITE_DISCARD;
-  }
-
-  // There should not be more than one finger down.
-  DCHECK(current_touch_ids_.size() <= 1);
-  if (type == ui::ET_TOUCH_MOVED) {
-    gesture_provider_.OnTouchEvent(event);
-    gesture_provider_.OnTouchEventAck(false);
+  if (!(type == ui::ET_TOUCH_RELEASED || type == ui::ET_TOUCH_CANCELLED ||

[aboxhall, 2014/07/30 00:25:15]

nit: this can be simplified to
if (type != ui::ET_TOUCH_RELEASED && type != ui::ET_TOUCH_CANCELLED && ...
Not much in it, but I find that way more readable as it's easy to miss the ! at
the start of the big disjunction there.

[evy, 2014/08/04 23:06:30]

Done.

+        type == ui::ET_TOUCH_MOVED || type == ui::ET_TOUCH_PRESSED)) {
+    NOTREACHED() << "Unexpected event type received: " << event.name();
+    return ui::EVENT_REWRITE_CONTINUE;
   }
-  if (type == ui::ET_TOUCH_RELEASED || type == ui::ET_TOUCH_CANCELLED) {
-    gesture_provider_.OnTouchEvent(event);
-    gesture_provider_.OnTouchEventAck(false);
-    if (current_touch_ids_.size() == 0) {
-      ResetToNoFingersDown();
-    }
+  // Send events to the gesture provider. If no gesture is registered before
+  // the tap timer times out, the state will change to wait for one finger
+  // and this function will stop being called.
+  gesture_provider_.OnTouchEvent(event);
+  gesture_provider_.OnTouchEventAck(false);
+  if (current_touch_ids_.size() == 0) {
+    ResetToNoFingersDown();
   }
   ProcessGestureEvents();
   return ui::EVENT_REWRITE_DISCARD;
@@ -475,6 +481,7 @@ ui::EventRewriteStatus TouchExplorationController::InWaitForOneFinger(
     NOTREACHED() << "Unexpected event type received: " << event.name();
     return ui::EVENT_REWRITE_CONTINUE;
   }
+
   if (current_touch_ids_.size() == 1) {
     EnterTouchToMouseMode();
     state_ = TOUCH_EXPLORATION;
@@ -507,6 +514,7 @@ ui::EventRewriteStatus TouchExplorationController::InSlideGesture(
     // Discard any pending gestures.
     delete gesture_provider_.GetAndResetPendingGestures();
     state_ = WAIT_FOR_ONE_FINGER;
+    VLOG_STATE();
     return EVENT_REWRITE_DISCARD;
   }
 
@@ -593,8 +601,9 @@ void TouchExplorationController::OnTapTimerFired() {
     case GESTURE_IN_PROGRESS:
       // Discard any pending gestures.
       delete gesture_provider_.GetAndResetPendingGestures();
-      EnterTouchToMouseMode();
-      state_ = TOUCH_EXPLORATION;
+      // Wait for one finger before returning to touch exploration.
+      send_gesture_events_ = true;
+      state_ = WAIT_FOR_ONE_FINGER;
       VLOG_STATE();
       break;
     default:
@@ -622,10 +631,12 @@ void TouchExplorationController::OnGestureEvent(
   if (VLOG_on_)
     VLOG(0) << " \n Gesture Triggered: " << gesture->name();
   if (type == ui::ET_GESTURE_SWIPE && state_ != SLIDE_GESTURE) {
-    if (VLOG_on_)
-      VLOG(0) << "Swipe!";
     delete gesture_provider_.GetAndResetPendingGestures();
     OnSwipeEvent(gesture);
+    send_gesture_events_ = true;
+    state_ = WAIT_FOR_ONE_FINGER;
+    VLOG_STATE();
+    tap_timer_.Stop();
     return;
   }
 }
@@ -693,24 +704,72 @@ void TouchExplorationController::SideSlideControl(ui::GestureEvent* gesture) {
   delegate_->SetOutputLevel(int(volume));
 }
 
-
 void TouchExplorationController::OnSwipeEvent(ui::GestureEvent* swipe_gesture) {
   // A swipe gesture contains details for the direction in which the swipe
   // occurred.
   GestureEventDetails event_details = swipe_gesture->details();
-  if (event_details.swipe_left()) {
-    DispatchShiftSearchKeyEvent(ui::VKEY_LEFT);
-    return;
-  } else if (event_details.swipe_right()) {
-    DispatchShiftSearchKeyEvent(ui::VKEY_RIGHT);
-    return;
-  } else if (event_details.swipe_up()) {
-    DispatchShiftSearchKeyEvent(ui::VKEY_UP);
-    return;
-  } else if (event_details.swipe_down()) {
-    DispatchShiftSearchKeyEvent(ui::VKEY_DOWN);
-    return;
+  int num_fingers = event_details.touch_points();
+  if(VLOG_on_)
+    VLOG(0) << "\nSwipe with " << num_fingers << " fingers.";
+  switch (num_fingers) {
+    case 1:
+      if (event_details.swipe_left()) {
+        DispatchShiftSearchKeyEvent(ui::VKEY_LEFT);

[aboxhall, 2014/07/30 00:25:15]

Speculation: it might be nice to keep track of these in a data structure rather
than in code like this. Since you're forced to check the direction manually, you
could have a set of maps something like:
map<int, base::Closure> left_swipe_gestures = ...
left_swipe_gestures[1] = base::Bind(&DispatchShiftSearchKeyEvent,
ui::VKEY_LEFT);
...
and then
if (event_details.swipe_left()) {
  left_swipe_gestures[num_fingers].Run()
} else if (event_details.swipe_right() ...
Other reviewers might think this is a silly idea, though :) You'd also need to
handle the case where no action was mapped for that combination of swipe
direction and num_fingers.

[evy, 2014/08/04 23:06:30]

This is pretty cool! I'm not that familiar with maps, closures, and binds in
C++, but I'll definitely take a look.
I'm going to upload what I have right now so reviewers can compare the two
approaches - and also because I'd like review on the rest of what I've done so
far :)

+        return;
+      } else if (event_details.swipe_right()) {
+        DispatchShiftSearchKeyEvent(ui::VKEY_RIGHT);
+        return;
+      } else if (event_details.swipe_up()) {
+        DispatchShiftSearchKeyEvent(ui::VKEY_UP);
+        return;
+      } else if (event_details.swipe_down()) {
+        DispatchShiftSearchKeyEvent(ui::VKEY_DOWN);
+        return;
+      }
+    case 2:
+      if (event_details.swipe_left()) {
+        DispatchKeyWithNoFlags(VKEY_BROWSER_BACK);
+        return;
+      } else if (event_details.swipe_right()) {
+        DispatchKeyWithNoFlags(VKEY_BROWSER_FORWARD);
+        return;
+      } else if (event_details.swipe_up()) {
+        DispatchShiftSearchKeyEvent(ui::VKEY_A);
+        return;
+      } else if (event_details.swipe_down()) {
+        DispatchShiftSearchKeyEvent(ui::VKEY_R);
+        return;
+      }
+    case 3:
+      if (event_details.swipe_up()) {
+        DispatchKeyWithNoFlags(ui::VKEY_PRIOR);
+        return;
+      } else if (event_details.swipe_down()) {
+        DispatchKeyWithNoFlags(ui::VKEY_NEXT);
+        return;
+      }
+      // Left/right gestures mapping?
+      return;
+    case 4:
+      if (event_details.swipe_left()) {
+        // TODO: scroll through tabs
+        return;
+      } else if (event_details.swipe_right()) {
+        // TODO: scroll through tabs
+        return;
+      } else if (event_details.swipe_up()) {
+        DispatchKeyWithNoFlags(VKEY_BROWSER_HOME);
+        return;
+      } else if (event_details.swipe_down()) {
+        DispatchKeyWithNoFlags(VKEY_BROWSER_REFRESH);
+        return;
+      }
   }
+  // If the user is swiping with more than the supported number of fingers,
+  // none of these cases will be hit.
+  // TODO: add some checks so the gesture doesn't get proccessed if there are
+  // more fingers than supported.
+  return;
 }
 
 int TouchExplorationController::FindEdgesWithinBounds(gfx::Point point,
@@ -742,19 +801,19 @@ int TouchExplorationController::FindEdgesWithinBounds(gfx::Point point,
 }
 
 void TouchExplorationController::DispatchShiftSearchKeyEvent(
-    const ui::KeyboardCode direction) {
-  // In order to activate the shortcut shift+search+<arrow key>
+    const ui::KeyboardCode third_key) {
+  // In order to activate the shortcut shift+search+<key>
   // three KeyPressed events must be dispatched in succession along
   // with three KeyReleased events.
   ui::KeyEvent shift_down = ui::KeyEvent(
       ui::ET_KEY_PRESSED, ui::VKEY_SHIFT, ui::EF_SHIFT_DOWN);
   ui::KeyEvent search_down = ui::KeyEvent(
       ui::ET_KEY_PRESSED, kChromeOSSearchKey, ui::EF_SHIFT_DOWN);
-  ui::KeyEvent direction_down =
-      ui::KeyEvent(ui::ET_KEY_PRESSED, direction, ui::EF_SHIFT_DOWN);
+  ui::KeyEvent third_key_down =
+      ui::KeyEvent(ui::ET_KEY_PRESSED, third_key, ui::EF_SHIFT_DOWN);
 
-  ui::KeyEvent direction_up =
-      ui::KeyEvent(ui::ET_KEY_RELEASED, direction, ui::EF_SHIFT_DOWN);
+  ui::KeyEvent third_key_up =
+      ui::KeyEvent(ui::ET_KEY_RELEASED, third_key, ui::EF_SHIFT_DOWN);
   ui::KeyEvent search_up = ui::KeyEvent(
       ui::ET_KEY_RELEASED, kChromeOSSearchKey, ui::EF_SHIFT_DOWN);
   ui::KeyEvent shift_up =
@@ -762,12 +821,26 @@ void TouchExplorationController::DispatchShiftSearchKeyEvent(
 
   DispatchEvent(&shift_down);
   DispatchEvent(&search_down);
-  DispatchEvent(&direction_down);
-  DispatchEvent(&direction_up);
+  DispatchEvent(&third_key_down);
+  DispatchEvent(&third_key_up);
   DispatchEvent(&search_up);
   DispatchEvent(&shift_up);
 }
 
+void TouchExplorationController::DispatchKeyWithNoFlags(
+    const ui::KeyboardCode key) {
+  ui::KeyEvent key_down = ui::KeyEvent(ui::ET_KEY_PRESSED, key, ui::EF_NONE);
+  ui::KeyEvent key_up = ui::KeyEvent(ui::ET_KEY_RELEASED, key, ui::EF_NONE);
+  DispatchEvent(&key_down);
+  DispatchEvent(&key_up);
+  if(VLOG_on_) {
+    VLOG(0) << "\nKey down: key code : " << key_down.key_code()
+            << ", flags: " << key_down.flags()
+            << "\nKey up: key code : " << key_up.key_code()
+            << ", flags: " << key_up.flags();
+  }
+}
+
 scoped_ptr<ui::Event> TouchExplorationController::CreateMouseMoveEvent(
     const gfx::PointF& location,
     int flags) {
@@ -811,6 +884,7 @@ void TouchExplorationController::ResetToNoFingersDown() {
   VLOG_STATE();
   if (tap_timer_.IsRunning())
     tap_timer_.Stop();
+  send_gesture_events_ = false;
 }
 
 void TouchExplorationController::VlogState(const char* function_name) {
@@ -874,12 +948,12 @@ const char* TouchExplorationController::EnumStateToString(State state) {
       return "GESTURE_IN_PROGRESS";
     case TOUCH_EXPLORE_SECOND_PRESS:
       return "TOUCH_EXPLORE_SECOND_PRESS";
-    case SLIDE_GESTURE:
-      return "SLIDE_GESTURE";
     case ONE_FINGER_PASSTHROUGH:
       return "ONE_FINGER_PASSTHROUGH";
     case WAIT_FOR_ONE_FINGER:
       return "WAIT_FOR_ONE_FINGER";
+    case SLIDE_GESTURE:
+      return "SLIDE_GESTURE";
   }
   return "Not a state";
 }