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 45 class IScrollTarget { 46 public: // interface 47 virtual void handleScrollBy(float xDelta, float yDelta)=0; 48 }; 49 50 class ScrollProxyView : public BView { 51 typedef BView _inherited; 52 public: ScrollProxyView(IScrollTarget * pTarget,BRect frame)53 ScrollProxyView(IScrollTarget* pTarget, BRect frame) : 54 m_pTarget(pTarget), 55 BView(frame, "scrollProxy", B_FOLLOW_LEFT|B_FOLLOW_TOP, 0) {} ~ScrollProxyView()56 virtual ~ScrollProxyView() {} 57 ScrollTo(BPoint where)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 66 protected: 67 IScrollTarget* m_pTarget; 68 }; 69 70 #endif /* __EMOON_ScrollHelpers_H__ */