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 41 namespace WebCore { 42 class EventHandler; 43 class IntSize; 44 class Node; 45 } 46 47 namespace blink { 48 49 // ViewportAnchor provides a way to anchor a viewport origin to a DOM node. 50 // In particular, the user supplies the current viewport (in CSS coordinates) 51 // and an anchor point (in view coordinates, e.g., (0, 0) == viewport origin, 52 // (0.5, 0) == viewport top center). The anchor point tracks the underlying DOM 53 // node; as the node moves or the view is resized, the viewport anchor maintains 54 // its orientation relative to the node, and the viewport origin maintains its 55 // orientation relative to the anchor. 56 class ViewportAnchor { 57 WTF_MAKE_NONCOPYABLE(ViewportAnchor); 58 public: 59 explicit ViewportAnchor(WebCore::EventHandler* eventHandler); 60 61 void setAnchor(const WebCore::IntRect& viewRect, const WebCore::FloatSize& anchorInViewCoords); 62 63 WebCore::IntPoint computeOrigin(const WebCore::IntSize& currentViewSize) const; 64 65 private: 66 WebCore::EventHandler* m_eventHandler; 67 68 WebCore::IntRect m_viewRect; 69 70 RefPtrWillBePersistent<WebCore::Node> m_anchorNode; 71 WebCore::LayoutRect m_anchorNodeBounds; 72 73 WebCore::FloatSize m_anchorInViewCoords; 74 WebCore::FloatSize m_anchorInNodeCoords; 75 }; 76 77 } // namespace blink 78 79 #endif 80