1 /* 2 * Copyright (C) 2010 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (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 #ifndef DragScrollTimer_h 32 #define DragScrollTimer_h 33 34 #include "IntSize.h" 35 #include "Timer.h" 36 #include "WebPoint.h" 37 38 namespace WebCore { class FrameView; } 39 40 namespace WebKit { 41 42 // 43 // Encapsulating a timer and associated state management for 44 // scroll-on-drag behaviour. 45 // 46 class DragScrollTimer { 47 public: 48 DragScrollTimer(); 49 ~DragScrollTimer(); 50 51 void fired(WebCore::Timer<DragScrollTimer>*) { update(); } 52 void triggerScroll(WebCore::FrameView*, const WebPoint&); 53 void stop(); 54 55 private: 56 void scroll(); 57 void update(); 58 WebCore::IntSize scrollDistanceFor(WebCore::FrameView*, const WebPoint&) const; 59 bool shouldScroll() const { return !m_lastDistance.isZero(); } 60 61 WebCore::Timer<DragScrollTimer> m_timer; 62 WebCore::FrameView* m_view; 63 WebCore::IntSize m_lastDistance; 64 bool m_scrolling; 65 }; 66 67 } // namespace WebKit 68 69 #endif 70
