diff -r 000000000000 -r 4f2f89ce4247 WebCore/page/TouchGestureHandler.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/page/TouchGestureHandler.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,143 @@
+/*
+    Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public License
+    along with this library; see the file COPYING.LIB.  If not, write to
+    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+    Boston, MA 02110-1301, USA.
+*/
+
+#include "config.h"
+#include "TouchGestureHandler.h"
+
+#include <math.h>
+
+#ifndef M_PI
+#define M_PI 3.1415926536
+#endif
+
+namespace WebCore {
+
+TouchGestureHandler::TouchGestureHandler()
+{
+    reset();
+}
+
+void TouchGestureHandler::updateRefreshNeededState(const Vector<const PlatformTouchPoint*>& touchPoints)
+{
+    // Number of touchpoints changed
+    if (touchPoints.size() != m_prevSize)
+        m_refreshNeeded = true;
+    else {
+        for (int i = 0; i < touchPoints.size(); ++i) {
+            // Touchpoints in pressed state or ids mismatch
+            if (touchPoints[i]->state() == PlatformTouchPoint::TouchPressed
+                || touchPoints[i]->id() != m_prevIds[i]) m_refreshNeeded = true;
+        }
+    }
+
+    m_prevSize = touchPoints.size();
+    for (int i = 0; i < touchPoints.size(); ++i)
+        m_prevIds[i] = touchPoints[i]->id();
+}
+
+void TouchGestureHandler::updateTouchPoints(const Vector<const PlatformTouchPoint*>& touchPoints)
+{
+    if (touchPoints.isEmpty())
+        return;
+
+    updateRefreshNeededState(touchPoints);
+
+    if (m_refreshNeeded) {
+        m_pos = calcPos(touchPoints);
+        IntSize clientOffset = touchPoints[0]->screenPos() - touchPoints[0]->pos();
+        m_screenPos = m_pos + clientOffset;
+
+        if (touchPoints.size() > 1) {
+            m_prevAngle = calcAngle(touchPoints[0]->pos(), touchPoints[1]->pos());
+            m_prevDistance = calcDistance(touchPoints[0]->pos(), touchPoints[1]->pos());
+        }
+        m_refreshNeeded = false;
+        return;
+    }
+
+    // Pan
+    IntPoint nextPos = calcPos(touchPoints);
+    m_translate += (nextPos - m_pos);
+    m_pos = nextPos;
+    IntSize clientOffset = touchPoints[0]->screenPos() - touchPoints[0]->pos();
+    m_screenPos = m_pos + clientOffset;
+
+    if (touchPoints.size() > 1) {
+        // Rotate
+        float angle = calcAngle(touchPoints[0]->pos(), touchPoints[1]->pos());
+        m_rotate += diffAngle(m_prevAngle, angle);
+        m_prevAngle = angle;
+
+        // Pinch
+        float distance = calcDistance(touchPoints[0]->pos(), touchPoints[1]->pos());
+        float nextScale = m_scale * (distance / (m_prevDistance ? m_prevDistance : 0.0001f));
+        m_scale = nextScale;
+        m_prevDistance = distance;
+    }
+}
+
+void TouchGestureHandler::reset()
+{
+    m_refreshNeeded = true;
+    m_scale = 1.0;
+    m_rotate = 0;
+    m_translate = IntPoint(0, 0);
+    m_pos = IntPoint(0, 0);
+    m_screenPos = IntPoint(0, 0);
+    m_prevSize = 0;
+}
+
+float TouchGestureHandler::calcAngle(const IntPoint& p1, const IntPoint& p2) const
+{
+    float deltaX = p1.x() - p2.x();
+    float deltaY = p1.y() - p2.y();
+    return atan2(deltaY, deltaX);
+}
+
+float TouchGestureHandler::diffAngle(float alpha, float beta) const
+{
+    float between = beta - alpha;
+
+    if (between > M_PI)
+        between -= 2 * M_PI;
+    else if (between < -M_PI)
+        between += 2 * M_PI;
+
+    return between;
+}
+
+IntPoint TouchGestureHandler::calcPos(const Vector<const PlatformTouchPoint*>& touchPoints) const
+{
+    if (touchPoints.size() == 1)
+        return touchPoints[0]->pos();
+
+    IntPoint pos;
+    pos.setX((touchPoints[0]->pos().x() + touchPoints[1]->pos().x()) / 2);
+    pos.setY((touchPoints[0]->pos().y() + touchPoints[1]->pos().y()) / 2);
+    return pos;
+}
+
+float TouchGestureHandler::calcDistance(const IntPoint& p1, const IntPoint& p2) const
+{
+    float dx = p1.x() - p2.x();
+    float dy = p1.y() - p2.y();
+    return sqrt(dx * dx + dy * dy);
+}
+
+}