/*
 * Copyright (c) 1999-2000, Eric Moon.
 * 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.
 *
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF TITLE, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR 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.
 */


// ScrollHelpers.h
// e.moon 9mar99
//
// An interface/driver view combination to simplify the task
// of redirecting a scroll bar: an invisible proxy view
// forwards scroll requests back to a scroll-handler.

#ifndef __EMOON_ScrollHelpers_H__
#define __EMOON_ScrollHelpers_H__

#include <View.h>
#include "debug_tools.h"

class IScrollTarget {
public:                 // interface
        virtual void handleScrollBy(float xDelta, float yDelta)=0;
};

class ScrollProxyView : public BView {
        typedef BView _inherited;
public:
        ScrollProxyView(IScrollTarget* pTarget, BRect frame) :
                m_pTarget(pTarget),
                BView(frame, "scrollProxy", B_FOLLOW_LEFT|B_FOLLOW_TOP, 0) {}
        virtual ~ScrollProxyView() {}
        
        virtual void ScrollTo(BPoint where) {
                float xDelta = where.x - Bounds().left;
                float yDelta = where.y - Bounds().top;
                _inherited::ScrollTo(where);
                ASSERT(m_pTarget);
                m_pTarget->handleScrollBy(xDelta, yDelta);
        }
        
protected:
        IScrollTarget*          m_pTarget;
};