Home | History | Annotate | Download | only in web 
      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