athena/util/drag_handle.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef ATHENA_UTIL_DRAG_HANDLE_H_
   6 #define ATHENA_UTIL_DRAG_HANDLE_H_
   7
   8 #include "athena/athena_export.h"
   9
  10 namespace views {
  11 class View;
  12 }
  13
  14 namespace athena {
  15 class DragHandleScrollDelegate {
  16  public:
  17   virtual ~DragHandleScrollDelegate() {}
  18
  19   // Beginning of a scroll gesture.
  20   virtual void HandleScrollBegin(float delta) = 0;
  21
  22   // End of the current scroll gesture with velocity |velocity|.
  23   virtual void HandleScrollEnd(float velocity) = 0;
  24
  25   // Update of the scroll position for the currently active scroll gesture.
  26   virtual void HandleScrollUpdate(float delta) = 0;
  27 };
  28
  29 enum DragHandleScrollDirection { DRAG_HANDLE_VERTICAL, DRAG_HANDLE_HORIZONTAL };
  30
  31 // Creates a handle view which notifies the delegate of the scrolls performed on
  32 // it.
  33 ATHENA_EXPORT views::View* CreateDragHandleView(
  34     DragHandleScrollDirection scroll_direction,
  35     DragHandleScrollDelegate* delegate,
  36     int preferred_width,
  37     int preferred_height);
  38
  39 }  // namespace athena
  40
  41 #endif  // ATHENA_UTIL_DRAG_HANDLE_H_