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 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
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 *
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#ifndef SD_SLIDESORTER_VISIBLE_AREA_MANAGER_HXX
#define SD_SLIDESORTER_VISIBLE_AREA_MANAGER_HXX

#include "controller/SlsAnimator.hxx"
#include "model/SlsSharedPageDescriptor.hxx"
#include <boost/noncopyable.hpp>
#include <boost/optional.hpp>

namespace sd { namespace slidesorter { namespace controller {


/** Manage requests for scrolling page objects into view.
*/
class VisibleAreaManager
    : public ::boost::noncopyable
{
public:
    VisibleAreaManager (SlideSorter& rSlideSorter);
    ~VisibleAreaManager (void);

    void ActivateCurrentSlideTracking (void);
    void DeactivateCurrentSlideTracking (void);
    bool IsCurrentSlideTrackingActive (void) const;

    /** Request the current slide to be moved into the visible area.
        This request is only obeyed when the current slide tracking is
        active.
        @see ActivateCurrentSlideTracking() and DeactivateCurrentSlideTracking()
    */
    void RequestCurrentSlideVisible (void);

    /** Request to make the specified page object visible.
    */
    void RequestVisible (
        const model::SharedPageDescriptor& rpDescriptor,
        const bool bForce = false);

    /** Temporarily disable the update of the visible area.
    */
    class TemporaryDisabler
    {
    public:
        TemporaryDisabler (SlideSorter& rSlideSorter);
        ~TemporaryDisabler (void);
    private:
        VisibleAreaManager& mrVisibleAreaManager;
    };

private:
    SlideSorter& mrSlideSorter;

    /** List of rectangle that someone wants to be moved into the visible
        area.
        Cleared on every call to ForgetVisibleRequests() and MakeVisible().
    */
    ::std::vector<Rectangle> maVisibleRequests;

    /** Animation id for a scroll animation that sets the top
        and left of the visible area to maRequestedVisibleTopLeft.
    */
    Animator::AnimationId mnScrollAnimationId;
    Point maRequestedVisibleTopLeft;
    Animator::AnimationMode meRequestedAnimationMode;
    bool mbIsCurrentSlideTrackingActive;
    int mnDisableCount;

    void MakeVisible (void);
    ::boost::optional<Point> GetRequestedTopLeft (void) const;
};


} } } // end of namespace ::sd::slidesorter::view

#endif