Adding split view divider widget.

athena/common/drag_handle.cc

Index: athena/common/drag_handle.cc
diff --git a/athena/common/drag_handle.cc b/athena/common/drag_handle.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f48dd234a7b1b7a5d9a95552570449898efe3658
--- /dev/null
+++ b/athena/common/drag_handle.cc
@@ -0,0 +1,175 @@
+// 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 "athena/common/drag_handle.h"
+
+#include "ui/views/background.h"
+#include "ui/views/layout/box_layout.h"
+#include "ui/views/view.h"
+#include "ui/views/widget/widget.h"
+
+namespace athena {
+namespace {
+
+const SkColor kDragHandleColorNormal = SK_ColorGRAY;
+const SkColor kDragHandleColorHot = SK_ColorWHITE;
+
+class DragHandleView : public views::View {
+ public:
+  explicit DragHandleView(DragHandle::ScrollDirection scroll_direction,
+                          DragHandle::ScrollDelegate* delegate,
+                          int preferred_width,
+                          int preferred_height);
+  virtual ~DragHandleView();
+
+ private:
+  enum State {
+    DEFAULT,
+    SCROLLING,
+  };
+
+  void SetColor(SkColor color);
+
+  void SetState(State state);
+
+  // views::View:
+  virtual gfx::Size GetPreferredSize() const OVERRIDE;
+  virtual void OnMouseEntered(const ui::MouseEvent& event) OVERRIDE;
+  virtual void OnMouseExited(const ui::MouseEvent& event) OVERRIDE;
+  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
+
+  State state_;
+  DragHandle::ScrollDelegate* delegate_;
+  DragHandle::ScrollDirection scroll_direction_;
+  SkColor color_;
+  float scroll_start_location_;
+  const int preferred_width_;
+  const int preferred_height_;
+
+  DISALLOW_COPY_AND_ASSIGN(DragHandleView);
+};
+
+DragHandleView::DragHandleView(DragHandle::ScrollDirection scroll_direction,
+                               DragHandle::ScrollDelegate* delegate,
+                               int preferred_width,
+                               int preferred_height)
+    : state_(DEFAULT),
+      delegate_(delegate),
+      scroll_direction_(scroll_direction),
+      color_(SK_ColorTRANSPARENT),
+      preferred_width_(preferred_width),
+      preferred_height_(preferred_height) {
+  SetColor(kDragHandleColorNormal);
+}
+
+DragHandleView::~DragHandleView() {
+}
+
+void DragHandleView::SetColor(SkColor color) {
+  if (color_ == color)
+    return;
+  color_ = color;
+  set_background(views::Background::CreateSolidBackground(color_));
+  SchedulePaint();
+}
+
+void DragHandleView::SetState(State state) {
+  if (state_ == state)
+    return;
+  state_ = state;
+  if (state == DEFAULT)
+    scroll_start_location_ = 0;
+}
+
+// views::View:
+gfx::Size DragHandleView::GetPreferredSize() const {
+  return gfx::Size(preferred_width_, preferred_height_);
+}
+
+void DragHandleView::OnMouseEntered(const ui::MouseEvent& event) {
+  SetColor(kDragHandleColorHot);
+}
+
+void DragHandleView::OnMouseExited(const ui::MouseEvent& event) {
+  SetColor(kDragHandleColorNormal);
+}
+
+void DragHandleView::OnGestureEvent(ui::GestureEvent* event) {
+  SkColor change_color = SK_ColorTRANSPARENT;
+  if (event->type() == ui::ET_GESTURE_BEGIN &&
+      event->details().touch_points() == 1) {
+    change_color = kDragHandleColorHot;
+  } else if (event->type() == ui::ET_GESTURE_END &&
+             event->details().touch_points() == 1) {
+    change_color = kDragHandleColorNormal;
+  }
+  if (change_color != SK_ColorTRANSPARENT) {
+    SetColor(change_color);
+    event->SetHandled();
+    return;
+  }
+
+  if (event->type() == ui::ET_GESTURE_SCROLL_BEGIN) {
+    if (!delegate_->HandleCanScroll() || state_ != DEFAULT)
+      return;
+    float delta;
+    if (scroll_direction_ == DragHandle::VERTICAL) {
+      delta = event->details().scroll_y_hint();
+      scroll_start_location_ = event->root_location().y();
+    } else {
+      delta = event->details().scroll_x_hint();
+      scroll_start_location_ = event->root_location().x();
+    }
+    delegate_->HandleScrollBegin(delta);
+    SetState(SCROLLING);
+    event->SetHandled();
+  } else if (event->type() == ui::ET_GESTURE_SCROLL_END) {
+    if (state_ != SCROLLING)
+      return;
+    delegate_->HandleScrollEnd();
+    SetColor(kDragHandleColorNormal);
+    SetState(DEFAULT);
+    event->SetHandled();
+  } else if (event->type() == ui::ET_SCROLL_FLING_START) {
+    if (state_ != SCROLLING)
+      return;
+    delegate_->HandleScrollEnd();

[sadrul, 2014/09/12 04:30:36]

Do we not want to take the velocity into consideration to decide whether to
complete the action or not?

[mfomitchev, 2014/09/12 20:49:07]

That sounds like a good idea. I was thinking of doing this for the bezel
gestures as well - swiping hard should probably switch to the next activity even
if you don't drag the handle far enough to the other side.
I created a separate bug to track this: crbug.com/413880

+    SetColor(kDragHandleColorNormal);
+    SetState(DEFAULT);
+    event->SetHandled();
+  } else if (event->type() == ui::ET_GESTURE_SCROLL_UPDATE) {
+    if (state_ != SCROLLING)
+      return;
+    float delta = scroll_direction_ == DragHandle::VERTICAL
+                      ? event->root_location().y() - scroll_start_location_
+                      : event->root_location().x() - scroll_start_location_;
+    delegate_->HandleScrollUpdate(delta);
+    event->SetHandled();
+  }
+}
+
+}  // namespace
+
+views::View* CreateDragHandleView(DragHandle::ScrollDirection scroll_direction,
+                                  DragHandle::ScrollDelegate* delegate,
+                                  int preferred_width,
+                                  int preferred_height,
+                                  int margin) {
+  views::View* content_view = new views::View;
+  content_view->set_background(
+      views::Background::CreateSolidBackground(SK_ColorBLACK));
+  views::BoxLayout* layout =
+      new views::BoxLayout(views::BoxLayout::kHorizontal, margin, margin, 0);
+  layout->set_main_axis_alignment(views::BoxLayout::MAIN_AXIS_ALIGNMENT_CENTER);
+  layout->set_cross_axis_alignment(
+      views::BoxLayout::CROSS_AXIS_ALIGNMENT_CENTER);
+  content_view->SetLayoutManager(layout);
+
+  views::View* view = new DragHandleView(
+      scroll_direction, delegate, preferred_width, preferred_height);
+  content_view->AddChildView(view);
+  return content_view;
+}
+
+}  // namespace athena