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      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 ScrollAxis { SCROLL_AXIS_HORIZONTAL, SCROLL_AXIS_VERTICAL };
     28 
     29   // Creates a PaginationController. Does not take ownership of |model|. The
     30   // |model| is required to outlive this PaginationController. |scroll_axis|
     31   // specifies the axis in which the pages will scroll.
     32   PaginationController(PaginationModel* model, ScrollAxis scroll_axis);
     33 
     34   ScrollAxis scroll_axis() const { return scroll_axis_; }
     35 
     36   // Handles a mouse wheel or touchpad scroll event in the area represented by
     37   // the PaginationModel. |offset| is the number of units scrolled in each axis.
     38   // Returns true if the event was captured and there was some room to scroll.
     39   bool OnScroll(const gfx::Vector2d& offset);
     40 
     41   // Handles a touch gesture event in the area represented by the
     42   // PaginationModel. Returns true if the event was captured.
     43   bool OnGestureEvent(const ui::GestureEvent& event, const gfx::Rect& bounds);
     44 
     45  private:
     46   PaginationModel* pagination_model_;  // Not owned.
     47   ScrollAxis scroll_axis_;
     48 };
     49 
     50 }  // namespace app_list
     51 
     52 #endif  // UI_APP_LIST_PAGINATION_CONTROLLER_H_
     53