/*
 * Copyright (c) 1999-2000, Eric Moon.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions, and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF TITLE, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


// MouseTrackingHelpers.h
// e.moon 8mar99
//
// Some helper classes for mouse tracking, designed to make
// it easier to delegate drag operations to a parent class
// (especially useful for pane-separator bars & other operations
//  in which a view is moved or resized as the user drags
//  within it.)
//
// HISTORY
//   e.moon 11may99: fixed m_bTracking bug (not init'd in ctor)
//                   fixed mouseTrackingBegin() documentation
//                   (point is in view, not screen, coords)

#ifndef __MouseTrackingHelpers_H__
#define __MouseTrackingHelpers_H__

#include <View.h>

#include "cortex_defs.h"
__BEGIN_CORTEX_NAMESPACE

class MouseTrackingSourceView;

// interface for a mouse-tracking destination
class IMouseTrackingDestination {
public:                                                 // operations
        IMouseTrackingDestination() { }
        virtual ~IMouseTrackingDestination() { }
        // a MouseTrackingSourceView has started tracking the mouse
        // (point is in pSource view coordinates)
        virtual void mouseTrackingBegin(
                MouseTrackingSourceView* pSource,
                uint32 buttons,
                BPoint point)=0;
        
        // mouse-tracking update from child view
        // (point is in screen coordinates)
        virtual void mouseTrackingUpdate(
                uint32 buttons,
                float xDelta,
                float yDelta,
                BPoint point)=0;
        
        // mouse-tracking done
        virtual void mouseTrackingEnd()=0;
};

// mouse-tracking 'source' view
// hands off to a destination view (by default its immediate
// parent)

class MouseTrackingSourceView : public BView {
        typedef BView _inherited;

public:                                                 // types & constants
        // these bits determine which mouse axes will be tracked
        // (ie. if TRACK_HORIZONTAL isn't set, mouseTrackUpdate()
        //  will always be called with xDelta == 0.0)
        enum mouse_tracking_flag_t {
                TRACK_HORIZONTAL = 1,
                TRACK_VERTICAL = 2
        };

public:                                                         // ctor/dtor
        MouseTrackingSourceView(
                BRect frame,
                const char* pName,
                uint32 resizeMode=B_FOLLOW_LEFT|B_FOLLOW_TOP,
                uint32 flags=B_WILL_DRAW|B_FRAME_EVENTS,
                uint32 trackingFlags=TRACK_HORIZONTAL|TRACK_VERTICAL);

        ~MouseTrackingSourceView();

        bool isTracking() const { return m_bTracking; }

        // get mouse-down point in screen coordinates; returns
        // B_OK on success, or B_ERROR if no longer tracking
        // the mouse.
        status_t getTrackingOrigin(BPoint* poPoint) const;

        // fetch/set the destination handler
        // (if not yet attached to a window, or if no parent
        // implements IMouseTrackDestination, trackingDestination()
        // returns 0)
        //
        // setting the destination handler isn't allowed if a tracking
        // operation is currently in progress

        IMouseTrackingDestination* trackingDestination() const {
                return m_pDest;
        }
        status_t setTrackingDestination(IMouseTrackingDestination* pDest);

public:                                                         // BView impl.

        // handle mouse events
        virtual void MouseDown(BPoint point);
        virtual void MouseMoved(BPoint point, uint32 transit,
                const BMessage* pMsg);
        virtual void MouseUp(BPoint point);

        // look for a default destination
        virtual void AttachedToWindow();

/*
        // track current frame rectangle
        virtual void FrameResized(float width, float height);
*/
protected:                                                      // members

        IMouseTrackingDestination*              m_pDest;
        uint32                          m_trackingFlags;

        // mouse-tracking state
        bool                                            m_bTracking;
        BPoint                          m_prevPoint; // in screen coords
        BPoint                          m_initPoint; // in screen coords
        
//      BRect                                   m_prevFrame;
};

__END_CORTEX_NAMESPACE
#endif /* __MouseTrackingHelpers_H__ */