ui/app_list/pagination_controller.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 UI_APP_LIST_PAGINATION_CONTROLLER_H_
   6 #define UI_APP_LIST_PAGINATION_CONTROLLER_H_
   7
   8 #include "ui/app_list/app_list_export.h"
   9
  10 namespace gfx {
  11 class Vector2d;
  12 class Rect;
  13 }
  14
  15 namespace ui {
  16 class GestureEvent;
  17 }
  18
  19 namespace app_list {
  20
  21 class PaginationModel;
  22
  23 // Receives user scroll events from various sources (mouse wheel, touchpad,
  24 // touch gestures) and manipulates a PaginationModel as necessary.
  25 class APP_LIST_EXPORT PaginationController {
  26  public:
  27   enum ScrollEventType { SCROLL_MOUSE_WHEEL, SCROLL_TOUCHPAD };
  28
  29   enum ScrollAxis { SCROLL_AXIS_HORIZONTAL, SCROLL_AXIS_VERTICAL };
  30
  31   // Creates a PaginationController. Does not take ownership of |model|. The
  32   // |model| is required to outlive this PaginationController. |scroll_axis|
  33   // specifies the axis in which the pages will scroll.
  34   PaginationController(PaginationModel* model, ScrollAxis scroll_axis);
  35
  36   ScrollAxis scroll_axis() const { return scroll_axis_; }
  37
  38   // Handles a mouse wheel or touchpad scroll event in the area represented by
  39   // the PaginationModel. |offset| is the number of units scrolled in each axis.
  40   // Returns true if the event was captured and there was some room to scroll.
  41   bool OnScroll(const gfx::Vector2d& offset, ScrollEventType type);
  42
  43   // Handles a touch gesture event in the area represented by the
  44   // PaginationModel. Returns true if the event was captured.
  45   bool OnGestureEvent(const ui::GestureEvent& event, const gfx::Rect& bounds);
  46
  47  private:
  48   PaginationModel* pagination_model_;  // Not owned.
  49   ScrollAxis scroll_axis_;
  50 };
  51
  52 }  // namespace app_list
  53
  54 #endif  // UI_APP_LIST_PAGINATION_CONTROLLER_H_