wip: Touch Text Selection Prototypes

ui/touch_selection/touch_selection_controller.cc

Index: ui/touch_selection/touch_selection_controller.cc
diff --git a/ui/touch_selection/touch_selection_controller.cc b/ui/touch_selection/touch_selection_controller.cc
index ec720b4280865ebdf66a4c1e49b4c73fa7b5324e..dbc7e5e47152df6b323f339c79ca4fa5ba3fb0a9 100644
--- a/ui/touch_selection/touch_selection_controller.cc
+++ b/ui/touch_selection/touch_selection_controller.cc
@@ -39,11 +39,208 @@ TouchHandleOrientation ToTouchHandleOrientation(SelectionBound::Type type) {
 
 }  // namespace
 
+class GranularityStrategy {
+ public:
+  virtual ~GranularityStrategy() {};
+  virtual void OnSelectionBoundsUpdated(const SelectionBound& start,
+                                        const SelectionBound& end) {};
+  virtual void OnHandleDragBegin(const gfx::PointF& position,
+                                 base::TimeTicks event_time,
+                                 TouchSelectionController* controller) {};
+  virtual TextSelectionGranularity OnHandleDragUpdate(
+      const gfx::PointF& position,
+      const gfx::PointF& line_position,
+      base::TimeTicks event_time,
+      bool end_handle_dragged) { return ui::CHARACTER_GRANULARITY; };
+ protected:
+  GranularityStrategy() {};
+};
+
+class DefaultGranularityStrategy : public GranularityStrategy {
+ public:
+  DefaultGranularityStrategy() {};
+  ~DefaultGranularityStrategy() override {};
+};
+
+class DirectionGranularityStrategy : public GranularityStrategy {
+ public:
+  DirectionGranularityStrategy() : granularity_(ui::CHARACTER_GRANULARITY) {};
+
+  ~DirectionGranularityStrategy() override {};
+
+  void OnSelectionBoundsUpdated(const SelectionBound& start,
+                                const SelectionBound& end) override {
+//    LOG(ERROR) << "Bounds updated: "
+//        << "start.y/2=" << (start.edge_bottom_rounded().y() + start.edge_top_rounded().y()) /2
+//        << ", start.x=" << start.edge_bottom_rounded().x()
+//        << ", end.y/2=" << (end.edge_bottom_rounded().y() + end.edge_top_rounded().y()) / 2
+//        << ", end.x=" << end.edge_bottom_rounded().x();
+
+    if (granularity_ == ui::WORD_GRANULARITY) {
+      granularity_threshold_start_ = start;
+      granularity_threshold_end_ = end;
+    }
+  };
+
+  void OnHandleDragBegin(const gfx::PointF& position,
+                         base::TimeTicks event_time,
+                         TouchSelectionController* controller) override {
+    // TODO(mfomitchev):
+    // Ideally we want word boundaries communicated in CompositorFrameMetadata
+    // (see RenderWidgetHostViewAura::OnSwapCompositorFrame)
+    granularity_threshold_start_ = controller->start();
+    granularity_threshold_end_ = controller->end();
+    farthest_dragging_handle_position_ = position;
+    granularity_ = ui::WORD_GRANULARITY;
+  };
+
+  // TODO(mfomitchev): perhaps this should depend on character size?
+  // tap_slop_ is too big, uses max_touch_move_in_pixels_for_click. Perhaps
+  // we should use  span_slop? See GestureConfiguration
+  const int kHandleDragSlop = 7;
+  TextSelectionGranularity OnHandleDragUpdate(
+      const gfx::PointF& position,
+      const gfx::PointF& line_position,
+      base::TimeTicks event_time,
+      bool end_handle_dragged) override {
+    if (end_handle_dragged) {
+      if (line_position.y() > granularity_threshold_end_.edge_bottom().y()) {
+        LOG(ERROR) << "Moved down a line - adjusting max_dragging_handle_position_";
+        farthest_dragging_handle_position_ = position;
+        if (granularity_ == ui::CHARACTER_GRANULARITY) {
+          LOG(ERROR) << "Moved down a line, switching to WORD_GRANULARITY";
+          granularity_ = ui::WORD_GRANULARITY;
+        }
+      } else if (line_position.y() < granularity_threshold_end_.edge_top().y()) {
+        LOG(ERROR) << "Moved up a line - adjusting max_dragging_handle_position_";
+        farthest_dragging_handle_position_ = position;
+        if (granularity_ == ui::CHARACTER_GRANULARITY) {
+          granularity_ = ui::WORD_GRANULARITY;
+          LOG(ERROR) << "Moved up a line - switching to WORD_GRANULARITY";
+        }
+      } else if (position.x() > farthest_dragging_handle_position_.x()) {
+        LOG(ERROR) << "Incrementing max_dragging_handle_position_";
+        farthest_dragging_handle_position_ = position;
+        if (granularity_ == ui::CHARACTER_GRANULARITY &&
+            position.x() > granularity_threshold_end_.edge_bottom().x()) {
+          granularity_ = ui::WORD_GRANULARITY;
+          LOG(ERROR) << "Moved right of granularity_threshold_end_,"
+              << " switching to WORD_GRANULARITY";
+        }
+      } else if (position.x() + kHandleDragSlop <
+          farthest_dragging_handle_position_.x()) {
+        if (granularity_ == ui::WORD_GRANULARITY) {
+          granularity_ = ui::CHARACTER_GRANULARITY;
+          LOG(ERROR) << "Moved left of max_dragging_handle_position_,"
+              << " switching to CHARACTER_GRANULARITY";
+        }
+      }
+    } else {  //!end_handle_dragged
+      if (line_position.y() < granularity_threshold_start_.edge_top().y() ||
+          line_position.y() > granularity_threshold_start_.edge_bottom().y()) {
+        // Line change
+        farthest_dragging_handle_position_ = position;
+        granularity_ = ui::WORD_GRANULARITY;
+      } else if (position.x() < farthest_dragging_handle_position_.x()) {
+        farthest_dragging_handle_position_ = position;
+        if (position.x() < granularity_threshold_start_.edge_bottom().x())
+          granularity_ = ui::WORD_GRANULARITY;
+      } else if (position.x() - kHandleDragSlop >
+          farthest_dragging_handle_position_.x()) {
+        granularity_ = ui::CHARACTER_GRANULARITY;
+      }
+    }
+    return granularity_;
+  }
+
+ private:
+  TextSelectionGranularity granularity_;
+  SelectionBound granularity_threshold_start_;
+  SelectionBound granularity_threshold_end_;
+  // If we go left of this by more than slop - switch to CHAR granularity
+  // For right handle - farthest down/right
+  // For left handle - farthest up/left
+  gfx::PointF farthest_dragging_handle_position_;
+
+  DISALLOW_COPY_AND_ASSIGN(DirectionGranularityStrategy);
+};
+
+class VelocityGranularityStrategy : public GranularityStrategy {
+ public:
+  VelocityGranularityStrategy() :
+    granularity_(ui::CHARACTER_GRANULARITY),
+    avg_velocity_(0.f),
+    filterTimeConstant_(kFilterTimeConstant),
+    velocityGranularityThreshold_(kVelocityGranularityThreshold) {};
+
+  ~VelocityGranularityStrategy() override {};
+
+  const float kFilterTimeConstant = 0.3f;   // half decay @ 300ms
+  const float kVelocityGranularityThreshold = 80.f;
+
+  void SetStrategyParameters(int halfDecayMs, int threshold) {
+    filterTimeConstant_ = halfDecayMs / 1000.f;
+    velocityGranularityThreshold_ = threshold;
+  }
+
+  void OnHandleDragBegin(const gfx::PointF& position,
+                         base::TimeTicks event_time,
+                         TouchSelectionController* controller) override {
+    last_dragging_handle_position_ = position;
+    avg_velocity_ = 0;
+    last_event_time_ = event_time;
+    granularity_ = ui::WORD_GRANULARITY;
+  };
+
+  TextSelectionGranularity OnHandleDragUpdate(
+      const gfx::PointF& position,
+      const gfx::PointF& line_position,
+      base::TimeTicks event_time,
+      bool end_handle_dragged) override {
+    float dist = (position - last_dragging_handle_position_).Length();
+    float dt = static_cast<float>((event_time - last_event_time_).InSecondsF());
+    float current_velocity = dist / dt;
+
+    if (avg_velocity_ == 0) {
+      avg_velocity_ = current_velocity;
+    } else {
+      float alpha = dt / (filterTimeConstant_ + dt);
+      avg_velocity_ += (current_velocity - avg_velocity_) * alpha;
+    }
+
+    if (avg_velocity_ > velocityGranularityThreshold_)
+      granularity_ = ui::WORD_GRANULARITY;
+    else
+      granularity_ = ui::CHARACTER_GRANULARITY;
+
+    LOG(ERROR) << "avg_velocity=" << avg_velocity_
+        << ", current_velocity=" << current_velocity;
+
+    last_dragging_handle_position_ = position;
+    last_event_time_ = event_time;
+
+    return granularity_;
+  };
+
+ private:
+  TextSelectionGranularity granularity_;
+  gfx::PointF last_dragging_handle_position_;
+  base::TimeTicks last_event_time_;
+  float avg_velocity_;
+
+  float filterTimeConstant_;
+  float velocityGranularityThreshold_;
+
+
+  DISALLOW_COPY_AND_ASSIGN(VelocityGranularityStrategy);
+};
+
 TouchSelectionController::TouchSelectionController(
     TouchSelectionControllerClient* client,
     base::TimeDelta tap_timeout,
     float tap_slop,
-    bool show_on_tap_for_empty_editable)
+    bool show_on_tap_for_empty_editable,
+    TextSelectionGranularityStrategy selection_granularity_strategy)
     : client_(client),
       tap_timeout_(tap_timeout),
       tap_slop_(tap_slop),
@@ -57,19 +254,43 @@ TouchSelectionController::TouchSelectionController(
       activate_selection_automatically_(false),
       selection_empty_(false),
       selection_editable_(false),
-      temporarily_hidden_(false) {
+      temporarily_hidden_(false),
+      selection_granularity_strategy_(selection_granularity_strategy) {
   DCHECK(client_);
+  switch (selection_granularity_strategy) {
+    case GRANULARITY_STRATEGY_DEFAULT:
+      granularity_strategy_.reset(new DefaultGranularityStrategy());
+      break;
+    case GRANULARITY_STRATEGY_DIRECTION:
+      granularity_strategy_.reset(new DirectionGranularityStrategy());
+      break;
+    case GRANULARITY_STRATEGY_VELOCITY:
+      granularity_strategy_.reset(new VelocityGranularityStrategy());
+      break;
+  }
 }
 
 TouchSelectionController::~TouchSelectionController() {
 }
 
+void TouchSelectionController::SetVelocityStrategyParameters(int halfDecayMs,
+                                                             int threshold) {
+  if (selection_granularity_strategy_ != GRANULARITY_STRATEGY_VELOCITY)
+    return;
+
+  VelocityGranularityStrategy* velocityStrategy =
+      static_cast<VelocityGranularityStrategy*>(granularity_strategy_.get());
+  velocityStrategy->SetStrategyParameters(halfDecayMs, threshold);
+}
+
 void TouchSelectionController::OnSelectionBoundsUpdated(
     const SelectionBound& start,
     const SelectionBound& end) {
   if (start == start_ && end_ == end)
     return;
 
+  granularity_strategy_->OnSelectionBoundsUpdated(start, end);
+
   start_ = start;
   end_ = end;
   start_orientation_ = ToTouchHandleOrientation(start_.type());
@@ -235,7 +456,8 @@ void TouchSelectionController::TryActivateSelection() {
   }
 }
 
-void TouchSelectionController::OnHandleDragBegin(const TouchHandle& handle) {
+void TouchSelectionController::OnHandleDragBegin(const TouchHandle& handle,
+                                                 base::TimeTicks event_time) {
   if (&handle == insertion_handle_.get()) {
     client_->OnSelectionEvent(INSERTION_DRAG_STARTED, handle.position());
     return;
@@ -245,30 +467,49 @@ void TouchSelectionController::OnHandleDragBegin(const TouchHandle& handle) {
   if (&handle == start_selection_handle_.get()) {
     base = end_selection_handle_->position() + GetEndLineOffset();
     extent = start_selection_handle_->position() + GetStartLineOffset();
+    // TODO: HACK
+    client_->SelectBetweenCoordinates(base, start_.edge_bottom_rounded() + GetStartLineOffset());
   } else {
     base = start_selection_handle_->position() + GetStartLineOffset();
     extent = end_selection_handle_->position() + GetEndLineOffset();
+    // TODO: HACK
+    client_->SelectBetweenCoordinates(base, end_.edge_bottom_rounded() + GetEndLineOffset());
   }
 
+  granularity_strategy_->OnHandleDragBegin(handle.position(), event_time, this);
+
   // When moving the handle we want to move only the extent point. Before doing
   // so we must make sure that the base point is set correctly.
-  client_->SelectBetweenCoordinates(base, extent);
+  // TODO: HACK - swallow the update
+  //client_->SelectBetweenCoordinates(base, extent);
+  //OnHandleDragUpdate(handle, handle.position());
 
   client_->OnSelectionEvent(SELECTION_DRAG_STARTED, handle.position());
 }
 
 void TouchSelectionController::OnHandleDragUpdate(const TouchHandle& handle,
-                                                  const gfx::PointF& position) {
+                                                  const gfx::PointF& position,
+                                                  base::TimeTicks event_time) {
+  // TODO: figure out RTL
+  // TODO: start/end can switch! Handle!
+  bool end_handle_dragged = &handle == end_selection_handle_.get();
   // As the position corresponds to the bottom left point of the selection
   // bound, offset it by half the corresponding line height.
-  gfx::Vector2dF line_offset = &handle == start_selection_handle_.get()
-                                   ? GetStartLineOffset()
-                                   : GetEndLineOffset();
+  gfx::Vector2dF line_offset = end_handle_dragged
+                                   ? GetEndLineOffset()
+                                   : GetStartLineOffset();
+
   gfx::PointF line_position = position + line_offset;
+
   if (&handle == insertion_handle_.get()) {
     client_->MoveCaret(line_position);
   } else {
-    client_->MoveRangeSelectionExtent(line_position, ui::CHARACTER_GRANULARITY);
+    TextSelectionGranularity granularity =
+        granularity_strategy_->OnHandleDragUpdate(position,
+                                                  line_position,
+                                                  event_time,
+                                                  end_handle_dragged);
+    client_->MoveRangeSelectionExtent(line_position, granularity);
   }
 }