1/*
2 * Copyright (c) 1999-2000, Eric Moon.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions, and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions, and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * 3. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF TITLE, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
23 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
26 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
27 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31
32// ScrollHelpers.h
33// e.moon 9mar99
34//
35// An interface/driver view combination to simplify the task
36// of redirecting a scroll bar: an invisible proxy view
37// forwards scroll requests back to a scroll-handler.
38
39#ifndef __EMOON_ScrollHelpers_H__
40#define __EMOON_ScrollHelpers_H__
41
42#include <View.h>
43#include "debug_tools.h"
44
45class IScrollTarget {
46public:			// interface
47	virtual void handleScrollBy(float xDelta, float yDelta)=0;
48};
49
50class ScrollProxyView : public BView {
51	typedef BView _inherited;
52public:
53	ScrollProxyView(IScrollTarget* pTarget, BRect frame) :
54		m_pTarget(pTarget),
55		BView(frame, "scrollProxy", B_FOLLOW_LEFT|B_FOLLOW_TOP, 0) {}
56	virtual ~ScrollProxyView() {}
57
58	virtual void ScrollTo(BPoint where) {
59		float xDelta = where.x - Bounds().left;
60		float yDelta = where.y - Bounds().top;
61		_inherited::ScrollTo(where);
62		ASSERT(m_pTarget);
63		m_pTarget->handleScrollBy(xDelta, yDelta);
64	}
65
66protected:
67	IScrollTarget*		m_pTarget;
68};
69
70#endif /* __EMOON_ScrollHelpers_H__ */