/*

 * Copyright (C) 2004, 2006 Apple Computer, Inc.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

 */

#ifndef ScrollBar_h

#define ScrollBar_h

#include "Shared.h"

#include "ScrollTypes.h"

#include <wtf/MathExtras.h>

namespace WebCore {

class GraphicsContext;

class IntRect;

class Scrollbar;

class PlatformMouseEvent;

// These match the numbers we use over in WebKit (WebFrameView.m).

#define LINE_STEP   40

#define PAGE_KEEP   40

enum ScrollbarControlSize { RegularScrollbar, SmallScrollbar, MiniScrollbar };

class ScrollbarClient {

public:

    virtual ~ScrollbarClient() {}

    virtual void valueChanged(Scrollbar*) = 0;

    // Used to obtain a window clip rect.

    virtual IntRect windowClipRect() const = 0;

};

class Scrollbar : public Shared<Scrollbar> {

protected:

    Scrollbar(ScrollbarClient*, ScrollbarOrientation, ScrollbarControlSize);

public:

    virtual ~Scrollbar() {}

    virtual bool isWidget() const = 0;

    ScrollbarOrientation orientation() const { return m_orientation; }

    int value() const { return lroundf(m_currentPos); } 

    ScrollbarControlSize controlSize() const { return m_controlSize; }

    void setSteps(int lineStep, int pageStep, int pixelsPerStep = 1);

    bool setValue(int);

    void setProportion(int visibleSize, int totalSize);

    bool scroll(ScrollDirection, ScrollGranularity, float multiplier = 1.0);

    virtual int width() const = 0;

    virtual int height() const = 0;

    virtual void setRect(const IntRect&) = 0;

    virtual void setEnabled(bool) = 0;

    virtual void paint(GraphicsContext*, const IntRect& damageRect) = 0;

    static bool hasPlatformScrollbars() {

        // To use the platform's built-in scrollbars by default, return true.  We may

        // support styled engine scrollbars someday, and some platforms may wish to not

        // implement a platform scrollbar at all by default.  That's what this method is for.

        return true;

    }

    // These methods are used for platform scrollbars to give :hover feedback.  They will not get called

    // when the mouse went down in a scrollbar, since it is assumed the scrollbar will start

    // grabbing all events in that case anyway.

    virtual bool handleMouseMoveEvent(const PlatformMouseEvent&) { return false; }

    virtual bool handleMouseOutEvent(const PlatformMouseEvent&) { return false; }

    // Used by some platform scrollbars to know when they've been released from capture.

    virtual bool handleMouseReleaseEvent(const PlatformMouseEvent&) { return false; }

protected:

    virtual void updateThumbPosition() = 0;

    virtual void updateThumbProportion() = 0;

    ScrollbarClient* client() const { return m_client; }

    ScrollbarClient* m_client;

    ScrollbarOrientation m_orientation;

    ScrollbarControlSize m_controlSize;

    int m_visibleSize;

    int m_totalSize;

    float m_currentPos;

    int m_lineStep;

    int m_pageStep;

    float m_pixelStep;

};

}

#endif