[Android] Composited selection handle rendering

content/browser/renderer_host/input/touch_selection_controller.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/renderer_host/input/touch_selection_controller.h"
+
+#include "base/logging.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+
+namespace content {
+
+TouchSelectionController::TouchSelectionController(
+    TouchSelectionControllerClient* client)
+    : client_(client),
+      start_orientation_(TOUCH_HANDLE_ORIENTATION_UNDEFINED),
+      start_visible_(false),
+      end_orientation_(TOUCH_HANDLE_ORIENTATION_UNDEFINED),
+      end_visible_(false),
+      is_insertion_active_(false),
+      allow_automatic_insertion_activation_(false),
+      is_selection_active_(false),
+      allow_automatic_selection_activation_(false),
+      selection_editable_(false),
+      selection_editable_for_last_update_(false) {
+  DCHECK(client_);
+  HideAndDisallowAutomaticShowing();
+}
+
+TouchSelectionController::~TouchSelectionController() {
+}
+
+void TouchSelectionController::OnSelectionBoundsChanged(
+    const gfx::RectF& start_rect,
+    TouchHandleOrientation start_orientation,
+    bool start_visible,
+    const gfx::RectF& end_rect,
+    TouchHandleOrientation end_orientation,
+    bool end_visible) {
+  if (!allow_automatic_selection_activation_ &&
+      !allow_automatic_insertion_activation_)
+    return;
+
+  if (start_rect_ == start_rect && end_rect_ == end_rect &&
+      start_orientation_ == start_orientation &&
+      end_orientation_ == end_orientation &&
+      start_visible_ == start_visible && end_visible_ == end_visible &&
+      selection_editable_ == selection_editable_for_last_update_)
+    return;
+
+  start_rect_ = start_rect;
+  start_orientation_ = start_orientation;
+  start_visible_ = start_visible;
+  end_rect_ = end_rect;
+  end_orientation_ = end_orientation;
+  end_visible_ = end_visible;
+  selection_editable_for_last_update_ = selection_editable_;
+
+  const bool is_selection_dragging =
+      is_selection_active_ && (start_selection_handle_->is_dragging() ||
+                               end_selection_handle_->is_dragging());
+
+  // It's possible that the bounds temporarily overlap while a selection handle
+  // is being dragged, incorrectly reporting a CENTER orientation.

[cjhopman, 2014/07/09 22:29:12]

Is it possible that I could have selection and then drag one handle to the other
and then release such that the handle is no longer dragging when we actually get
the updated selection bounds?

(I actually just tried playing around a bit with this with the current
implementation and this can definitely happen and is easy to trigger. Even
better, is that you can get the end drag while there are actually multiple
updates still in flight such that you get one updated selection bounds where
start == end and orientation is center followed by another where start != end.)

I don't know if there is a simple way to handle that case.

[jdduke (slow), 2014/07/10 02:08:39]

Hmm, you're quite right... perhaps we require that, once a selection is active,
it can only be deactivated if the orientation becomes undefined or it's
explicitly hidden.  Maybe only enforce that if a gesture has occurred? I'll
probably do that as a follow-up, keeping the current behavior but I'll file a
bug.

+  if (is_selection_dragging) {
+    if (start_orientation_ == TOUCH_HANDLE_CENTER)
+      start_orientation_ = start_selection_handle_->orientation();
+    if (end_orientation_ == TOUCH_HANDLE_CENTER)
+      end_orientation_ = end_selection_handle_->orientation();
+  }
+
+  const gfx::PointF start = GetStartPosition();
+  const gfx::PointF end = GetEndPosition();
+  if (start != end || is_selection_dragging) {
+    OnSelectionChanged();
+    return;
+  }
+
+  if (start_orientation_ == TOUCH_HANDLE_CENTER) {
+    OnInsertionChanged();
+    return;
+  }
+
+  HideAndDisallowAutomaticShowing();
+}
+
+bool TouchSelectionController::WillHandleTouchEvent(
+    const ui::MotionEvent& event) {
+  if (is_insertion_active_) {
+    DCHECK(insertion_handle_);
+    return insertion_handle_->WillHandleTouchEvent(event);
+  }
+
+  if (is_selection_active_) {
+    DCHECK(start_selection_handle_);
+    DCHECK(end_selection_handle_);
+    return start_selection_handle_->WillHandleTouchEvent(event) ||
+           end_selection_handle_->WillHandleTouchEvent(event);
+  }
+
+  return false;
+}
+
+void TouchSelectionController::AllowAutomaticInsertionShowing() {
+  if (allow_automatic_insertion_activation_)
+    return;
+  allow_automatic_insertion_activation_ = true;
+  if (!is_insertion_active_ && !is_selection_active_)
+    ResetCachedValues();
+}
+
+void TouchSelectionController::AllowAutomaticSelectionShowing() {
+  if (allow_automatic_selection_activation_)
+    return;
+  allow_automatic_selection_activation_ = true;
+  if (!is_insertion_active_ && !is_selection_active_)
+    ResetCachedValues();
+}
+
+void TouchSelectionController::HideAndDisallowAutomaticShowing() {
+  DeactivateInsertion();
+  DeactivateSelection();
+  allow_automatic_insertion_activation_ = false;
+  allow_automatic_selection_activation_ = false;
+}
+
+void TouchSelectionController::OnSelectionEditable(bool editable) {
+  if (selection_editable_ == editable)
+    return;
+  selection_editable_ = editable;
+  if (!selection_editable_)
+    DeactivateInsertion();
+}
+
+bool TouchSelectionController::Animate(base::TimeTicks frame_time) {
+  if (is_insertion_active_)
+    return insertion_handle_->Animate(frame_time);
+
+  if (is_selection_active_) {
+    bool needs_animate = start_selection_handle_->Animate(frame_time);
+    needs_animate |= end_selection_handle_->Animate(frame_time);
+    return needs_animate;
+  }
+
+  return false;
+}
+
+void TouchSelectionController::OnHandleDragBegin(const TouchHandle& handle) {
+  if (&handle == insertion_handle_.get())
+    return;
+
+  if (&handle == start_selection_handle_.get()) {
+    fixed_handle_position_ = end_selection_handle_->position() -
+                             gfx::Vector2dF(0, GetEndLineHeight() / 2.f);
+  } else {
+    fixed_handle_position_ = start_selection_handle_->position() -
+                             gfx::Vector2dF(0, GetStartLineHeight() / 2.f);
+  }
+}
+
+void TouchSelectionController::OnHandleDragUpdate(const TouchHandle& handle,
+                                                  const gfx::PointF& position) {
+  // As the position corresponds to the bottom left point of the selection
+  // bound, offset it by half the corresponding line height.
+  float half_line_height = &handle == end_selection_handle_.get()
+                               ? GetEndLineHeight() / 2.f
+                               : GetStartLineHeight() / 2.f;
+  gfx::PointF line_position = position - gfx::Vector2dF(0, half_line_height);
+  if (&handle == insertion_handle_.get()) {
+    client_->MoveCaret(line_position);
+  } else {
+    client_->SelectBetweenCoordinates(fixed_handle_position_, line_position);
+  }
+}
+
+void TouchSelectionController::OnHandleDragEnd(const TouchHandle& handle) {
+}
+
+void TouchSelectionController::OnHandleTapped(const TouchHandle& handle) {
+  if (insertion_handle_ && &handle == insertion_handle_.get())
+    client_->OnSelectionEvent(INSERTION_TAPPED, GetStartPosition());
+}
+
+void TouchSelectionController::SetNeedsAnimate() {
+  client_->SetNeedsAnimate();
+}
+
+scoped_ptr<TouchHandleDrawable> TouchSelectionController::CreateDrawable() {
+  return client_->CreateDrawable();
+}
+
+void TouchSelectionController::OnInsertionChanged() {
+  DeactivateSelection();
+
+  if (!allow_automatic_insertion_activation_ || !selection_editable_)
+    return;
+
+  bool was_active = is_insertion_active_;
+  gfx::PointF position = GetStartPosition();
+  if (!was_active)
+    ActivateInsertion();
+  else
+    client_->OnSelectionEvent(INSERTION_MOVED, position);
+
+  insertion_handle_->SetVisible(
+      start_visible_,
+      was_active ? TouchHandle::ANIMATION_SMOOTH : TouchHandle::ANIMATION_NONE);
+
+  insertion_handle_->SetPosition(position);
+}
+
+void TouchSelectionController::OnSelectionChanged() {
+  DeactivateInsertion();
+
+  if (!allow_automatic_selection_activation_)
+    return;
+
+  const bool was_active = is_selection_active_;
+  ActivateSelection();
+
+  const TouchHandle::AnimationStyle animation =
+      was_active ? TouchHandle::ANIMATION_SMOOTH : TouchHandle::ANIMATION_NONE;
+  start_selection_handle_->SetVisible(start_visible_, animation);
+  end_selection_handle_->SetVisible(end_visible_, animation);
+
+  start_selection_handle_->SetPosition(GetStartPosition());
+  end_selection_handle_->SetPosition(GetEndPosition());
+}
+
+void TouchSelectionController::ActivateInsertion() {
+  DCHECK(!is_selection_active_);
+
+  if (!insertion_handle_)
+    insertion_handle_.reset(new TouchHandle(this, TOUCH_HANDLE_CENTER));
+
+  if (!is_insertion_active_) {
+    is_insertion_active_ = true;
+    client_->OnSelectionEvent(INSERTION_SHOWN, GetStartPosition());
+  }
+}
+
+void TouchSelectionController::DeactivateInsertion() {
+  if (!is_insertion_active_)
+    return;
+  DCHECK(insertion_handle_);
+  insertion_handle_->Hide();
+  is_insertion_active_ = false;
+  client_->OnSelectionEvent(INSERTION_CLEARED, gfx::PointF());
+}
+
+void TouchSelectionController::ActivateSelection() {
+  DCHECK(!is_insertion_active_);
+
+  if (!start_selection_handle_)
+    start_selection_handle_.reset(new TouchHandle(this, start_orientation_));
+  else
+    start_selection_handle_->SetOrientation(start_orientation_);
+
+  if (!end_selection_handle_)
+    end_selection_handle_.reset(new TouchHandle(this, end_orientation_));
+  else
+    end_selection_handle_->SetOrientation(end_orientation_);
+
+  if (!is_selection_active_) {
+    is_selection_active_ = true;
+    client_->OnSelectionEvent(SELECTION_SHOWN, GetStartPosition());
+  }
+}
+
+void TouchSelectionController::DeactivateSelection() {
+  if (!is_selection_active_)
+    return;
+  DCHECK(start_selection_handle_);
+  DCHECK(end_selection_handle_);
+  start_selection_handle_->Hide();
+  end_selection_handle_->Hide();
+  is_selection_active_ = false;
+  client_->OnSelectionEvent(SELECTION_CLEARED, gfx::PointF());
+}
+
+void TouchSelectionController::ResetCachedValues() {
+  start_rect_ = gfx::RectF();
+  end_rect_ = gfx::RectF();
+  start_orientation_ = TOUCH_HANDLE_ORIENTATION_UNDEFINED;
+  end_orientation_ = TOUCH_HANDLE_ORIENTATION_UNDEFINED;
+  start_visible_ = false;
+  end_visible_ = false;
+  selection_editable_for_last_update_ = false;
+}
+
+gfx::PointF TouchSelectionController::GetStartPosition() const {
+  return start_rect_.bottom_left();
+}
+
+gfx::PointF TouchSelectionController::GetEndPosition() const {
+  return end_rect_.bottom_left();
+}
+
+float TouchSelectionController::GetStartLineHeight() const {
+  return start_rect_.height();
+}
+
+float TouchSelectionController::GetEndLineHeight() const {
+  return end_rect_.height();
+}
+
+}  // namespace content