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DocFlowDrag.h

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//345678901234567890123456789012345678901234567890123456789012345678901234567890
// Author: Richard van Balen
#ifndef OglGui_DocFlowDrag_h
#define OglGui_DocFlowDrag_h

#ifndef OglGui_Window_h
#include "OglGui/Window.h"
#endif

#ifndef OglGui_DocDimensions_h
#include "OglGui/DocDimensions.h"
#endif

/*
#ifndef OglGui_time_included
#include <time.h>
#define OglGui_time_included
#endif
*/

#ifndef OglGui_RepeateTimer_h
#include "OglGui/RepeatTimer.h"
#endif

namespace OglGui {

// RvB: NOTE RepeatTimer only for test purpose.
// Will be removed in future
class DocFlowDrag : RepeatTimer
{
public:
    DocFlowDrag()
    {
        mFlowing = mFlowDragging = false;
        mMyMouseButton = oglLeftButton;
        mFlowPageThresh = 1500;
        mFlowPageExtra = 0;
        mKineticScrolling = true;
        mFriction = -500;
        //SetRepeatDelays(50,50);
        SetRepeatDelays(0,0);
    }

    void SetDocWnd(Window* wnd, DocDimensions* doc)
    {
        mFlowWnd = wnd;
        mFlowDoc = doc;
    }

    void    Friction(double f)              { mFriction = f; }
    double  Friction()                      { return mFriction; }
    void    UseMouseButton(int btn)         { mMyMouseButton = btn; }

    void SetFlowPageExtra(int extra)
    {
        mFlowPageExtra = extra;
    }

    void FlowPageThreshold(double t)
    {
        mFlowPageThresh = t;
    }

    void ClampDocY(int docY)
    {
        int docH = mFlowDoc->DocH();
        int wndH = mFlowWnd->H();
        if (docY > 0 || docY < -docH + wndH)
        {
            mFlowWnd->SetAlwaysDraw(mFlowing = false);
            docY = (docY>0) ? 0 : -docH + wndH;
            mFlowWnd->UpdateScene();
        }
        mFlowDoc->DocY(docY);
    }

    void FlowDragDisplay()
    {
        if (!mFlowing)
            return;

        int     docY = mFlowDoc->DocY();
        int     wndH = mFlowWnd->H();
        float   d;

        if (mOldDocY != docY)
        {
            mFlowWnd->SetAlwaysDraw(mFlowing=false);
            return;
        }

        if (mKineticScrolling)
        {
            float   t    = (OglClock() - mFlowDragStartTime);
            float   endT = fabs(mFlowSpeed / mFriction);
            //printf("t %f endT %f flowSpeed %f\n", t, endT, mFlowSpeed);
            if (t >= endT)
            {
                t = endT;
                mFlowWnd->SetAlwaysDraw(mFlowing=false);
                mFlowWnd->UpdateScene();
            }
            d = mFlowSpeed*t + (0.5*(mFlowSpeed>0?1:-1)*mFriction * (t*t));
            docY = mFlowStartY - d;
        }
        else
        {
            // To prevent rushing by images that cause flicker
            if (mFlowSpeed > mFlowPageThresh || mFlowSpeed <-mFlowPageThresh)
            {
                d = (mFlowSpeed>0) ? -wndH+mFlowPageExtra : wndH-mFlowPageExtra;
                if (RepeatTime())
                    docY += d;
            }
            else
            {
                d = -mFlowSpeed * (OglClock()-mFlowDragStartTime);
                docY = mFlowStartY + d;
            }
        }
        ClampDocY(docY);
        mOldDocY = mFlowDoc->DocY();
    }

    void MouseFunc(int msg, int but, int state, int x, int y)
    {
        if (msg == oglMouseDown && but == mMyMouseButton)
        {
            mKineticScrolling = !(state & oglControl);
            if (mFlowing)
                mFlowWnd->SetAlwaysDraw(mFlowing = false);
            mFlowDragging = true;
            mFlowDragDiff = 0;
            mFlowDragStartY = mFlowDragLastY = y;
            mFlowDragStartTime = OglClock();
        }
        if (msg == oglMouseMove && mFlowDragging)
        {
            mFlowDragDiff = mFlowDragLastY - y;
            ClampDocY(mFlowDoc->DocY() - mFlowDragDiff);
            mFlowDragLastY = y;
        }
        if (mFlowDragging && msg == oglMouseUp && but == mMyMouseButton)
        {
            mOldDocY = mFlowStartY = mFlowDoc->DocY();
            mFlowDragging = false;
            mFlowSpeed = ((double)mFlowDragStartY-y) /
                         (OglClock() - mFlowDragStartTime);
            //printf("FlowSpeed %f\n", mFlowSpeed);
            if (abs(mFlowDragDiff) < 3)
                mFlowSpeed = 0;
            if (mFlowSpeed > 100 || mFlowSpeed < -100)
                mFlowWnd->SetAlwaysDraw(mFlowing = true);
            mFlowDragStartTime = OglClock();
            StartRepeatTime();
        }
        if (!(state & mMyMouseButton))
            mFlowDragging = false;
    }

    void KeyboardFunc(int c, int state)
    {
        if (c>='0' && c <= '9')
            SetRepeatDelays((c-'0')*10,(c-'0')*10);
    }

protected:
    DocDimensions*              mFlowDoc;
    Window*                     mFlowWnd;

    bool                        mKineticScrolling;
    bool                        mFlowing;
    bool                        mFlowDragging;
    int                         mMyMouseButton;
    int                         mOldDocY;
    int                         mFlowDragDiff;
    int                         mFlowDragStartY;
    int                         mFlowDragLastY;
    int                         mFlowStartY;
    int                         mFlowPageExtra;
    double                      mFlowSpeed;
    double                      mFlowPageThresh;
    double                      mFriction;
    double                      mFlowDragStartTime;
};
} // namespace OglGui
#endif

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