1/* 2 * Copyright (C) 2013 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 ViewportAnchor_h 32#define ViewportAnchor_h 33 34#include "platform/geometry/FloatSize.h" 35#include "platform/geometry/IntPoint.h" 36#include "platform/geometry/IntRect.h" 37#include "platform/geometry/LayoutRect.h" 38#include "platform/heap/Handle.h" 39#include "wtf/RefCounted.h" 40 41namespace blink { 42 43class EventHandler; 44class IntSize; 45class Node; 46class ScrollView; 47 48// ViewportAnchor provides a way to anchor a viewport origin to a DOM node. 49// In particular, the user supplies the current viewport (in CSS coordinates) 50// and an anchor point (in view coordinates, e.g., (0, 0) == viewport origin, 51// (0.5, 0) == viewport top center). The anchor point tracks the underlying DOM 52// node; as the node moves or the view is resized, the viewport anchor maintains 53// its orientation relative to the node, and the viewport origin maintains its 54// orientation relative to the anchor. 55class ViewportAnchor { 56 STACK_ALLOCATED(); 57public: 58 explicit ViewportAnchor(EventHandler*); 59 60 void setAnchor(const IntRect& outerViewRect, const IntRect& innerViewRect, const FloatSize& anchorInViewCoords); 61 62 void computeOrigins(const ScrollView&, const FloatSize& innerSize, 63 IntPoint& mainFrameOffset, FloatPoint& pinchViewportOffset) const; 64 65private: 66 FloatPoint getInnerOrigin(const FloatSize& innerSize) const; 67 68private: 69 RawPtrWillBeMember<EventHandler> m_eventHandler; 70 71 // Inner viewport origin in the reference frame of the document in CSS pixels 72 FloatPoint m_pinchViewportInDocument; 73 74 // Inner viewport origin in the reference frame of the outer viewport 75 // normalized to the outer viewport size. 76 FloatSize m_normalizedPinchViewportOffset; 77 78 RefPtrWillBeMember<Node> m_anchorNode; 79 LayoutRect m_anchorNodeBounds; 80 81 FloatSize m_anchorInInnerViewCoords; 82 FloatSize m_anchorInNodeCoords; 83}; 84 85} // namespace blink 86 87#endif 88