Support touch scroll gestures in menus.

views/controls/menu/submenu_view.cc

 // Copyright (c) 2011 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 "views/controls/menu/submenu_view.h"
 
+#include <algorithm>
+
+#include "base/compiler_specific.h"
 #include "ui/base/accessibility/accessible_view_state.h"
 #include "ui/gfx/canvas.h"
 #include "views/controls/menu/menu_config.h"
 #include "views/controls/menu/menu_controller.h"
 #include "views/controls/menu/menu_host.h"
 #include "views/controls/menu/menu_scroll_view_container.h"
 #include "views/widget/root_view.h"
 #include "views/widget/widget.h"
 
 namespace {
@@ skipping 15 matching lines @@
 const char SubmenuView::kViewClassName[] = "views/SubmenuView";
 
 SubmenuView::SubmenuView(MenuItemView* parent)
     : parent_menu_item_(parent),
       host_(NULL),
       drop_item_(NULL),
       drop_position_(MenuDelegate::DROP_NONE),
       scroll_view_container_(NULL),
       max_accelerator_width_(0),
       minimum_preferred_width_(0),
-      resize_open_menu_(false) {
+      resize_open_menu_(false),
+      ALLOW_THIS_IN_INITIALIZER_LIST(
+          scroll_animator_(new ScrollAnimator(this))) {
   DCHECK(parent);
   // We'll delete ourselves, otherwise the ScrollView would delete us on close.
   set_parent_owned(false);
 }
 
 SubmenuView::~SubmenuView() {
   // The menu may not have been closed yet (it will be hidden, but not
   // necessarily closed).
   Close();
 
@@ skipping 182 matching lines @@
         first_vis_index++;
     }
     ScrollRectToVisible(gfx::Rect(gfx::Point(0, scroll_target),
                                   vis_bounds.size()));
     vis_bounds = GetVisibleBounds();
   }
 
   return true;
 }
 
+ui::GestureStatus SubmenuView::OnGestureEvent(const GestureEvent& e) {
+  switch (e.type()) {
+    case ui::ET_GESTURE_SCROLL_BEGIN:
+      scroll_animator_->Stop();
+      break;
+    case ui::ET_GESTURE_SCROLL_UPDATE:
+      OnScroll(0, e.delta_y());
+      break;
+    case ui::ET_GESTURE_SCROLL_END:
+      if (e.delta_y() != 0.0f)
+        scroll_animator_->Start(0, e.delta_y());
+      break;
+    default:
+      break;
+  }
+  return ui::GESTURE_STATUS_CONSUMED;
+}
+
 bool SubmenuView::IsShowing() {
   return host_ && host_->IsMenuHostVisible();
 }
 
 void SubmenuView::ShowAt(Widget* parent,
                          const gfx::Rect& bounds,
                          bool do_capture) {
   if (host_) {
     host_->ShowMenuHost(do_capture);
   } else {
@@ skipping 133 matching lines @@
       item_bounds.Offset(0, item_bounds.height() - kDropIndicatorHeight / 2);
       item_bounds.set_height(kDropIndicatorHeight);
       return item_bounds;
 
     default:
       // Don't render anything for on.
       return gfx::Rect();
   }
 }
 
+void SubmenuView::OnScroll(float dx, float dy) {
+  const gfx::Rect& vis_bounds = GetVisibleBounds();
+  const gfx::Rect& full_bounds = bounds();
+  int x = vis_bounds.x();
+  int y = vis_bounds.y() - static_cast<int>(dy);
+  // clamp y to [0, full_height - vis_height)
+  y = std::max(y, 0);
+  y = std::min(y, full_bounds.height() - vis_bounds.height() - 1);
+  gfx::Rect new_vis_bounds(x, y, vis_bounds.width(), vis_bounds.height());
+  if (new_vis_bounds != vis_bounds)
+    ScrollRectToVisible(new_vis_bounds);
+}
+
 }  // namespace views