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// Copyright (c) 2010 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_BITMAP_SCROLL_BAR_H_
#define VIEWS_CONTROLS_SCROLLBAR_BITMAP_SCROLL_BAR_H_
#pragma once
#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 {
namespace {
class BitmapScrollBarThumb;
}
///////////////////////////////////////////////////////////////////////////////
//
// BitmapScrollBar
//
// A ScrollBar subclass that implements a scroll bar rendered using bitmaps
// that the user provides. There are bitmaps for the up and down buttons, as
// well as for the thumb and track. This is intended for creating UIs that
// have customized, non-native appearances, like floating HUDs etc.
//
// Maybe TODO(beng): (Cleanup) If we need to, we may want to factor rendering
// out of this altogether and have the user supply
// Background impls for each component, and just use those
// to render, so that for example we get native theme
// rendering.
//
///////////////////////////////////////////////////////////////////////////////
class BitmapScrollBar : public ScrollBar,
public ButtonListener,
public ContextMenuController,
public Menu::Delegate {
public:
BitmapScrollBar(bool horizontal, bool show_scroll_buttons);
virtual ~BitmapScrollBar() { }
// Get the bounds of the "track" area that the thumb is free to slide within.
gfx::Rect GetTrackBounds() const;
// A list of parts that the user may supply bitmaps for.
enum ScrollBarPart {
// The button used to represent scrolling up/left by 1 line.
PREV_BUTTON = 0,
// The button used to represent scrolling down/right by 1 line.
// IMPORTANT: The code assumes the prev and next
// buttons have equal width and equal height.
NEXT_BUTTON,
// The top/left segment of the thumb on the scrollbar.
THUMB_START_CAP,
// The tiled background image of the thumb.
THUMB_MIDDLE,
// The bottom/right segment of the thumb on the scrollbar.
THUMB_END_CAP,
// The grippy that is rendered in the center of the thumb.
THUMB_GRIPPY,
// The tiled background image of the thumb track.
THUMB_TRACK,
PART_COUNT
};
// Sets the bitmap to be rendered for the specified part and state.
void SetImage(ScrollBarPart part,
CustomButton::ButtonState state,
SkBitmap* bitmap);
// 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();
virtual void Paint(gfx::Canvas* canvas);
virtual void Layout();
virtual bool OnMousePressed(const MouseEvent& event);
virtual void OnMouseReleased(const MouseEvent& event, bool canceled);
virtual bool OnMouseWheel(const MouseWheelEvent& event);
virtual bool OnKeyPressed(const KeyEvent& event);
// BaseButton::ButtonListener overrides:
virtual void ButtonPressed(Button* sender, const views::Event& event);
// ScrollBar overrides:
virtual void Update(int viewport_size,
int content_size,
int contents_scroll_offset);
virtual int GetLayoutSize() const;
virtual int GetPosition() const;
// ContextMenuController overrides.
virtual void ShowContextMenu(View* source,
const gfx::Point& p,
bool is_mouse_gesture);
// Menu::Delegate overrides:
virtual std::wstring GetLabel(int id) const;
virtual bool IsCommandEnabled(int id) const;
virtual void ExecuteCommand(int id);
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);
// The thumb needs to be able to access the part images.
friend BitmapScrollBarThumb;
SkBitmap* images_[PART_COUNT][CustomButton::BS_COUNT];
// 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_;
// Up/Down/Left/Right buttons and the Thumb.
ImageButton* prev_button_;
ImageButton* next_button_;
BitmapScrollBarThumb* thumb_;
// 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_;
// True if the scroll buttons at each end of the scroll bar should be shown.
bool show_scroll_buttons_;
DISALLOW_COPY_AND_ASSIGN(BitmapScrollBar);
};
} // namespace views
#endif // VIEWS_CONTROLS_SCROLLBAR_BITMAP_SCROLL_BAR_H_
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