text: // Copyright (c) 2012 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.
  
  #ifndef ASH_WM_COMMON_WINDOW_RESIZER_H_
  #define ASH_WM_COMMON_WINDOW_RESIZER_H_
  
  #include <memory>
  
  #include "ash/wm/common/ash_wm_common_export.h"
  #include "ash/wm/common/drag_details.h"
  #include "ash/wm/common/window_state.h"
  #include "base/macros.h"
  #include "ui/wm/public/window_move_client.h"
  
  namespace gfx {
  class Rect;
  }
  
  namespace ash {
  namespace wm {
  class WmWindow;
  }
  
  // WindowResizer is used by ToplevelWindowEventFilter to handle dragging, moving
  // or resizing a window. All coordinates passed to this are in the parent
  // windows coordinates.
  class ASH_WM_COMMON_EXPORT WindowResizer {
   public:
    // Constants to identify the type of resize.
    static const int kBoundsChange_None;
    static const int kBoundsChange_Repositions;
    static const int kBoundsChange_Resizes;
  
    // Used to indicate which direction the resize occurs in.
    static const int kBoundsChangeDirection_None;
    static const int kBoundsChangeDirection_Horizontal;
    static const int kBoundsChangeDirection_Vertical;
  
    explicit WindowResizer(wm::WindowState* window_state);
    virtual ~WindowResizer();
  
    // Returns a bitmask of the kBoundsChange_ values.
    static int GetBoundsChangeForWindowComponent(int component);
  
    // Returns a bitmask of the kBoundsChange_ values.
    static int GetPositionChangeDirectionForWindowComponent(int window_component);
  
    // Invoked to drag/move/resize the window. |location| is in the coordinates
    // of the window supplied to the constructor. |event_flags| is the event
    // flags from the event.
    virtual void Drag(const gfx::Point& location, int event_flags) = 0;
  
    // Invoked to complete the drag.
    virtual void CompleteDrag() = 0;
  
    // Reverts the drag.
    virtual void RevertDrag() = 0;
  
    // Returns the target window the resizer was created for.
    wm::WmWindow* GetTarget() const {
      return window_state_ ? window_state_->window() : nullptr;
    }
    // See comment for |DragDetails::initial_location_in_parent|.
    const gfx::Point& GetInitialLocation() const {
      return window_state_->drag_details()->initial_location_in_parent;
    }
  
    // Drag parameters established when drag starts.
    const DragDetails& details() const { return *window_state_->drag_details(); }
  
   protected:
    gfx::Rect CalculateBoundsForDrag(const gfx::Point& location);
  
    static bool IsBottomEdge(int component);
  
    // WindowState of the drag target.
    wm::WindowState* window_state_;
  
   private:
    // In case of touch resizing, adjusts deltas so that the border is positioned
    // just under the touch point.
    void AdjustDeltaForTouchResize(int* delta_x, int* delta_y);
  
    // Returns the new origin of the window. The arguments are the difference
    // between the current location and the initial location.
    gfx::Point GetOriginForDrag(int delta_x, int delta_y);
  
    // Returns the size of the window for the drag.
    gfx::Size GetSizeForDrag(int* delta_x, int* delta_y);
  
    // Returns the width of the window.
    int GetWidthForDrag(int min_width, int* delta_x);
  
    // Returns the height of the drag.
    int GetHeightForDrag(int min_height, int* delta_y);
  
    DISALLOW_COPY_AND_ASSIGN(WindowResizer);
  };
  
  // Creates a WindowResizer for |window|. Returns a unique_ptr with null if
  // |window| should not be resized nor dragged.
  ASH_WM_COMMON_EXPORT std::unique_ptr<WindowResizer> CreateWindowResizer(
      wm::WmWindow* window,
      const gfx::Point& point_in_parent,
      int window_component,
      aura::client::WindowMoveSource source);
  
  }  // namespace ash
  
  #endif  // ASH_WM_COMMON_WINDOW_RESIZER_H_
  