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* Copyright (C) 2013 Google Inc. All rights reserved.
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#ifndef ViewportAnchor_h
#define ViewportAnchor_h
#include "platform/geometry/FloatSize.h"
#include "platform/geometry/IntPoint.h"
#include "platform/geometry/IntRect.h"
#include "platform/geometry/LayoutRect.h"
#include "wtf/RefCounted.h"
namespace WebCore {
class EventHandler;
class IntSize;
class Node;
}
namespace blink {
// ViewportAnchor provides a way to anchor a viewport origin to a DOM node.
// In particular, the user supplies the current viewport (in CSS coordinates)
// and an anchor point (in view coordinates, e.g., (0, 0) == viewport origin,
// (0.5, 0) == viewport top center). The anchor point tracks the underlying DOM
// node; as the node moves or the view is resized, the viewport anchor maintains
// its orientation relative to the node, and the viewport origin maintains its
// orientation relative to the anchor.
class ViewportAnchor {
WTF_MAKE_NONCOPYABLE(ViewportAnchor);
public:
explicit ViewportAnchor(WebCore::EventHandler* eventHandler);
void setAnchor(const WebCore::IntRect& viewRect, const WebCore::FloatSize& anchorInViewCoords);
WebCore::IntPoint computeOrigin(const WebCore::IntSize& currentViewSize) const;
private:
WebCore::EventHandler* m_eventHandler;
WebCore::IntRect m_viewRect;
RefPtr<WebCore::Node> m_anchorNode;
WebCore::LayoutRect m_anchorNodeBounds;
WebCore::FloatSize m_anchorInViewCoords;
WebCore::FloatSize m_anchorInNodeCoords;
};
} // namespace blink
#endif