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// 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.
#ifndef VIEWS_CONTROLS_SCROLLBAR_BASE_SCROLL_BAR_H_
#define VIEWS_CONTROLS_SCROLLBAR_BASE_SCROLL_BAR_H_
#pragma once
#include "views/context_menu_controller.h"
#include "views/controls/button/image_button.h"
#include "views/controls/menu/menu.h"
#include "views/controls/scrollbar/scroll_bar.h"
#include "views/repeat_controller.h"
namespace views {
class BaseScrollBarThumb;
///////////////////////////////////////////////////////////////////////////////
//
// BaseScrollBar
//
///////////////////////////////////////////////////////////////////////////////
class VIEWS_EXPORT BaseScrollBar : public ScrollBar,
public ContextMenuController,
public Menu::Delegate {
public:
BaseScrollBar(bool horizontal, BaseScrollBarThumb* thumb);
virtual ~BaseScrollBar() { }
// Get the bounds of the "track" area that the thumb is free to slide within.
virtual gfx::Rect GetTrackBounds() const = 0;
// An enumeration of different amounts of incremental scroll, representing
// events sent from different parts of the UI/keyboard.
enum ScrollAmount {
SCROLL_NONE = 0,
SCROLL_START,
SCROLL_END,
SCROLL_PREV_LINE,
SCROLL_NEXT_LINE,
SCROLL_PREV_PAGE,
SCROLL_NEXT_PAGE,
};
// Scroll the contents by the specified type (see ScrollAmount above).
void ScrollByAmount(ScrollAmount amount);
// Scroll the contents to the appropriate position given the supplied
// position of the thumb (thumb track coordinates). If |scroll_to_middle| is
// true, then the conversion assumes |thumb_position| is in the middle of the
// thumb rather than the top.
void ScrollToThumbPosition(int thumb_position, bool scroll_to_middle);
// Scroll the contents by the specified offset (contents coordinates).
void ScrollByContentsOffset(int contents_offset);
// View overrides:
virtual gfx::Size GetPreferredSize() OVERRIDE = 0;
virtual void Layout() OVERRIDE = 0;
virtual bool OnMousePressed(const MouseEvent& event) OVERRIDE;
virtual void OnMouseReleased(const MouseEvent& event) OVERRIDE;
virtual void OnMouseCaptureLost() OVERRIDE;
virtual bool OnKeyPressed(const KeyEvent& event) OVERRIDE;
virtual bool OnMouseWheel(const MouseWheelEvent& event) OVERRIDE;
// ScrollBar overrides:
virtual void Update(int viewport_size,
int content_size,
int contents_scroll_offset) OVERRIDE;
virtual int GetLayoutSize() const OVERRIDE = 0;
virtual int GetPosition() const OVERRIDE;
// ContextMenuController overrides.
virtual void ShowContextMenuForView(View* source,
const gfx::Point& p,
bool is_mouse_gesture) OVERRIDE;
// Menu::Delegate overrides:
virtual std::wstring GetLabel(int id) const OVERRIDE;
virtual bool IsCommandEnabled(int id) const OVERRIDE;
virtual void ExecuteCommand(int id) OVERRIDE;
protected:
// View overrides:
virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE = 0;
BaseScrollBarThumb* GetThumb() const;
CustomButton::ButtonState GetThumbTrackState() const;
// Wrapper functions that calls the controller. We need this since native
// scrollbars wrap around a different scrollbar. When calling the controller
// we need to pass in the appropriate scrollbar. For normal scrollbars it's
// the |this| scrollbar, for native scrollbars it's the native scrollbar used
// to create this.
virtual void ScrollToPosition(int position);
virtual int GetScrollIncrement(bool is_page, bool is_positive);
private:
// Called when the mouse is pressed down in the track area.
void TrackClicked();
// Responsible for scrolling the contents and also updating the UI to the
// current value of the Scroll Offset.
void ScrollContentsToOffset();
// Returns the size (width or height) of the track area of the ScrollBar.
int GetTrackSize() const;
// Calculate the position of the thumb within the track based on the
// specified scroll offset of the contents.
int CalculateThumbPosition(int contents_scroll_offset) const;
// Calculates the current value of the contents offset (contents coordinates)
// based on the current thumb position (thumb track coordinates). See
// |ScrollToThumbPosition| for an explanation of |scroll_to_middle|.
int CalculateContentsOffset(int thumb_position,
bool scroll_to_middle) const;
// Called when the state of the thumb track changes (e.g. by the user
// pressing the mouse button down in it).
void SetThumbTrackState(CustomButton::ButtonState state);
BaseScrollBarThumb* thumb_;
// The size of the scrolled contents, in pixels.
int contents_size_;
// The current amount the contents is offset by in the viewport.
int contents_scroll_offset_;
// The state of the scrollbar track. Typically, the track will highlight when
// the user presses the mouse on them (during page scrolling).
CustomButton::ButtonState thumb_track_state_;
// The last amount of incremental scroll that this scrollbar performed. This
// is accessed by the callbacks for the auto-repeat up/down buttons to know
// what direction to repeatedly scroll in.
ScrollAmount last_scroll_amount_;
// An instance of a RepeatController which scrolls the scrollbar continuously
// as the user presses the mouse button down on the up/down buttons or the
// track.
RepeatController repeater_;
// The position of the mouse within the scroll bar when the context menu
// was invoked.
int context_menu_mouse_position_;
DISALLOW_COPY_AND_ASSIGN(BaseScrollBar);
};
} // namespace views
#endif // VIEWS_CONTROLS_SCROLLBAR_BASE_SCROLL_BAR_H_
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