1 /*

     2 * Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of the License "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:   Implementation of scrolling decelerator

    15 *

    16 */

    17 

    18 

    19 // INCLUDE FILES

    20 #include <../bidi.h>

    21 #include "WebScrollingDecelerator.h"

    22 #include "WebView.h"

    23 #include "WebFrame.h"

    24 #include "WebFrameView.h"

    25 #include "WebPageScrollHandler.h"

    26 #include "PlatformScrollbar.h"

    27 

    28 // constants

    29 const int KRecordSize = 4;

    30 

    31 // The following deceleration curve is generated by a script

    32 // It lists the timeout dt values in microseconds.

    33 const int KDecelCurveSize = 10;

    34 

    35 const int KScrollIntervalTimeout = 40000; // scroll timer interval in microseconds

    36 

    37 // ============================ MEMBER FUNCTIONS ===============================

    38 

    39 // -----------------------------------------------------------------------------

    40 // WebScrollingDecelerator::NewL

    41 // The two-phase Symbian constructor

    42 // -----------------------------------------------------------------------------

    43 //

    44 

    45 WebScrollingDecelerator* WebScrollingDecelerator::NewL(WebView& webView)

    46 {

    47     WebScrollingDecelerator* self = new (ELeave) WebScrollingDecelerator(webView);

    48 

    49     CleanupStack::PushL(self);

    50     self->ConstructL();

    51     CleanupStack::Pop(); //self

    52     return self;

    53 }

    54 

    55 // -----------------------------------------------------------------------------

    56 // WebScrollingDecelerator::WebScrollingDecelerator

    57 // C++ default constructor can NOT contain any code, that

    58 // might leave.

    59 // -----------------------------------------------------------------------------

    60 //

    61 WebScrollingDecelerator::WebScrollingDecelerator(WebView& webView)

    62 : CTimer(EPriorityHigh), m_webView( webView )

    63 {

    64 }

    65 

    66 // -----------------------------------------------------------------------------

    67 // WebScrollingDecelerator::ConstructL

    68 // -----------------------------------------------------------------------------

    69 void WebScrollingDecelerator::ConstructL()

    70 {

    71     CTimer::ConstructL();

    72     CActiveScheduler::Add( this );

    73     m_dragPosition.Reset();

    74 }

    75 

    76 // -----------------------------------------------------------------------------

    77 // Destructor

    78 // -----------------------------------------------------------------------------

    79 WebScrollingDecelerator::~WebScrollingDecelerator()

    80 {

    81     Cancel();

    82 }

    83 

    84 // -----------------------------------------------------------------------------

    85 // WebScrollingDecelerator::updatePos

    86 // update record of position

    87 // -----------------------------------------------------------------------------

    88 //

    89 void WebScrollingDecelerator::updatePos()

    90 {

    91     if (m_dragPosition.Count() >= KRecordSize)

    92       {

    93         // pop item from front   

    94         m_dragPosition.Remove(0);

    95       }

    96     

    97     // and add this one to the end

    98     TPoint currPosition = m_webView.pageScrollHandler()->currentScrollingFrameView()->contentPos();

    99     m_dragPosition.Append(currPosition);

   100 }

   101 

   102 // -----------------------------------------------------------------------------

   103 // WebScrollingDecelerator::startDecel

   104 // initialize and start deceleration

   105 // -----------------------------------------------------------------------------

   106 //

   107 void WebScrollingDecelerator::startDecelL()

   108 {

   109     int count = m_dragPosition.Count();

   110         

   111     m_normalizedCurrentPosition.iX = m_webView.pageScrollHandler()->currentScrollingFrameView()->contentPos().iX * 100;

   112     m_normalizedCurrentPosition.iY = m_webView.pageScrollHandler()->currentScrollingFrameView()->contentPos().iY * 100;

   113     

   114     if (count > 0)

   115       {     

   116 

   117       // set the delta based upon the change span of points collected averaged over the span, so long as we have moved

   118         int dx = (m_dragPosition[count - 1].iX - m_dragPosition[0].iX)* 100;

   119         int dy = (m_dragPosition[count - 1].iY - m_dragPosition[0].iY) * 100;

   120  

   121         if (abs(dx) > 0 || abs(dy) > 0)

   122             {           

   123             m_scrolldelta.SetXY( (dx/count), (dy/count) );

   124             WebFrameView* view = m_webView.pageScrollHandler()->currentScrollingFrameView();

   125             

   126             m_scrolldelta = view->toDocCoords(m_scrolldelta);

   127             

   128             // init num steps

   129             m_numscrollsteps = 0;

   130 

   131             // call the RunL function directly, this first time. CTimer will call it from now on.

   132             m_decelelatorSwitch = ETrue;

   133             

   134             RunL();

   135             }

   136         }

   137         m_dragPosition.Reset();

   138 }

   139 

   140 // -----------------------------------------------------------------------------

   141 // WebScrollingDecelerator::RunL

   142 // continue deceleration

   143 // -----------------------------------------------------------------------------

   144 //

   145 void WebScrollingDecelerator::RunL()

   146 {

   147   WebFrameView* scrollingView = m_webView.pageScrollHandler()->currentScrollingFrameView();

   148     // use a pre-calulated deceleration curve to calculate dt

   149     if ((m_numscrollsteps >= KDecelCurveSize ) || !m_decelelatorSwitch)

   150       {

   151         // done

   152         Cancel();

   153         m_webView.setViewIsScrolling(false);

   154         return;

   155       }

   156     

   157     // step to next

   158     m_numscrollsteps++;

   159 

   160     // do the scrolling

   161     

   162     if (m_webView.pageScrollHandler() && scrollingView) {

   163         

   164         TPoint newpos;

   165         

   166         /* With each step decrease m_scrolldelta by 50% */

   167         m_scrolldelta.iX = m_scrolldelta.iX >> 1;

   168         m_scrolldelta.iY = m_scrolldelta.iY >> 1;

   169                 

   170         m_normalizedCurrentPosition += m_scrolldelta;

   171         newpos.iX = m_normalizedCurrentPosition.iX/100;

   172         newpos.iY = m_normalizedCurrentPosition.iY/100;

   173         scrollingView->scrollTo(newpos);

   174 

   175         if (scrollingView->vScrollbar()) {

   176             scrollingView->vScrollbar()->setValue(newpos.iY);

   177         }

   178         if (scrollingView->hScrollbar()) {

   179             scrollingView->hScrollbar()->setValue(newpos.iX);

   180         }

   181 

   182         After(KScrollIntervalTimeout);

   183     }

   184 }

   185 

   186 //  End of File