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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 UI_VIEWS_CONTROLS_SCROLLBAR_BASE_SCROLL_BAR_THUMB_H_
#define UI_VIEWS_CONTROLS_SCROLLBAR_BASE_SCROLL_BAR_THUMB_H_
#include "ui/gfx/geometry/size.h"
#include "ui/views/controls/button/custom_button.h"
#include "ui/views/controls/scrollbar/scroll_bar.h"
#include "ui/views/view.h"
namespace gfx {
class Canvas;
}
namespace views {
class BaseScrollBar;
///////////////////////////////////////////////////////////////////////////////
//
// BaseScrollBarThumb
//
// A view that acts as the thumb in the scroll bar track that the user can
// drag to scroll the associated contents view within the viewport.
//
///////////////////////////////////////////////////////////////////////////////
class VIEWS_EXPORT BaseScrollBarThumb : public View {
public:
explicit BaseScrollBarThumb(BaseScrollBar* scroll_bar);
~BaseScrollBarThumb() override;
// Sets the size (width or height) of the thumb to the specified value.
void SetSize(int size);
// Retrieves the size (width or height) of the thumb.
int GetSize() const;
// Sets the position of the thumb on the x or y axis.
void SetPosition(int position);
// Gets the position of the thumb on the x or y axis.
int GetPosition() const;
// View overrides:
gfx::Size GetPreferredSize() const override = 0;
protected:
// View overrides:
void OnPaint(gfx::Canvas* canvas) override = 0;
void OnMouseEntered(const ui::MouseEvent& event) override;
void OnMouseExited(const ui::MouseEvent& event) override;
bool OnMousePressed(const ui::MouseEvent& event) override;
bool OnMouseDragged(const ui::MouseEvent& event) override;
void OnMouseReleased(const ui::MouseEvent& event) override;
void OnMouseCaptureLost() override;
CustomButton::ButtonState GetState() const;
// Update our state and schedule a repaint when the mouse moves over us.
void SetState(CustomButton::ButtonState state);
BaseScrollBar* scroll_bar() { return scroll_bar_; }
private:
// The BaseScrollBar that owns us.
BaseScrollBar* scroll_bar_;
int drag_start_position_;
// The position of the mouse on the scroll axis relative to the top of this
// View when the drag started.
int mouse_offset_;
// The current state of the thumb button.
CustomButton::ButtonState state_;
DISALLOW_COPY_AND_ASSIGN(BaseScrollBarThumb);
};
} // namespace views
#endif // UI_VIEWS_CONTROLS_SCROLLBAR_BASE_SCROLL_BAR_THUMB_H_
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