ganeswidgets/src/hgdrag.cpp
changeset 0 89c329efa980
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ganeswidgets/src/hgdrag.cpp	Mon Apr 19 14:40:06 2010 +0300
@@ -0,0 +1,94 @@
+/*
+* Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description: Container for pan (drag) gesture -related data and logic.
+*
+*/
+
+#include "hgdrag.h"
+#include "trace.h"
+
+HgDrag::HgDrag()
+{
+}
+
+void HgDrag::reset(const qreal delta, const qreal viewPos)
+{
+    mViewPosAtStart = viewPos;
+    mDuration.start();
+    mLength = 0;
+    mCumulatedDelta = 0;
+    mDirection = delta;
+    mDirectionChange = 0;
+    INFO("Drag reset at view pos:" << mViewPosAtStart);
+}
+
+qreal HgDrag::update(const qreal delta, const qreal viewPos, const qreal itemWidth)
+{
+//    INFO("delta:" << delta << ", direction:" << mDirection);
+    if ((delta > 0 && mDirection < 0) || (delta < 0 && mDirection > 0))
+    {
+        if (mDirectionChange > 2)
+        {
+            mDirectionChange = 0;
+            reset(delta, viewPos);
+        }
+        else
+        {
+            mDirectionChange++;
+        }
+    }
+    else
+    {
+        mDirection = delta;
+        mDirectionChange = 0;
+    }
+
+    mCumulatedDelta = (mCumulatedDelta+delta)/2;
+    mLength += delta/itemWidth;
+    qreal pos = mViewPosAtStart-mLength;
+//  INFO("Drag len:" << mLength << ", new pos:" << pos);
+    return pos;
+}
+
+bool HgDrag::finish(const qreal viewPos, bool stopToFullItem, qreal &newPos)
+{
+    int dt = mDuration.elapsed();
+    if (dt > 10)
+    {
+        qreal t = (qreal)dt/1000;
+        INFO("Drag len:" << mLength << ", duration:" << t << ", cumulated:" << mCumulatedDelta);
+        if (qAbs(mCumulatedDelta) > 4)
+        {
+            newPos = viewPos-mLength/t * 0.5f;
+        }
+        else
+        {
+            newPos = mViewPosAtStart-mLength;
+        }
+        if (stopToFullItem)
+        {
+            qreal i = floorf(newPos);
+            newPos = (newPos - i > 0.5f) ? ceilf(newPos) : i;
+        }
+
+        return true;
+    }
+    return false;
+}
+
+qreal HgDrag::viewPosAtStart() const
+{
+    return mViewPosAtStart;
+}
+