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__ */