Cleanup involving scrollto and dragresistance factor

1 files changed, 57 insertions, 63 deletions

diff --git a/qkineticscroller.cpp b/qkineticscroller.cpp
index cace269..951b9f7 100644
--- a/qkineticscroller.cpp
+++ b/qkineticscroller.cpp
@@ -722,6 +722,7 @@ void QKineticScrollerPrivate::timerEventWhileDragging()
 {
     if (!dragDistance.isNull()) {
         qDebug() << "timerEventWhileDragging" << dragDistance;
+
         setContentPositionHelper(-dragDistance);
         dragDistance = QPointF(0, 0);
     }
@@ -851,8 +852,6 @@ void QKineticScrollerPrivate::setState(QKineticScroller::State newstate)
             }
         }
 
-        overshootPosition /= overshootDragResistanceFactor;
-
         break;
 
     case QKineticScroller::StateScrolling:
@@ -863,8 +862,7 @@ void QKineticScrollerPrivate::setState(QKineticScroller::State newstate)
         scrollAbsoluteTimer.start();
 
         if (state == QKineticScroller::StateDragging) {
-            overshootPosition *= overshootDragResistanceFactor;
-
+            // TODO: better calculate StartTime using the current releaseVelocity
             overshootStartTimeX = overshootStartTimeY = qreal(scrollAbsoluteTimer.elapsed()) / 1000 - M_PI / (overshootSpringConstantRoot * 2);
             overshootVelocity = overshootPosition / pixelPerMeter * overshootSpringConstantRoot;
         }
@@ -881,7 +879,7 @@ void QKineticScrollerPrivate::setState(QKineticScroller::State newstate)
     the viewport.
 
     If the specified point cannot be reached, the contents are scrolled to the
-    nearest valid position.
+    nearest valid position (in this case the scroller might or might not overshoot).
 
     The scrolling speed will be calculated so that the given position will
     be reached after a platform-defined time span (1 second for Maemo 5).
@@ -1008,10 +1006,16 @@ void QKineticScrollerPrivate::setContentPositionHelper(const QPointF &deltaPos)
 {
     Q_Q(QKineticScroller);
 
+    if (state == QKineticScroller::StateDragging && overshootDragResistanceFactor)
+        overshootPosition /= overshootDragResistanceFactor;
+
     QPointF oldPos = q->contentPosition() + overshootPosition;
     QPointF newPos = oldPos + deltaPos;
     QPointF maxPos = q->maximumContentPosition();
 
+    QPointF oldScrollToDist = scrollToPosition - oldPos;
+    QPointF newScrollToDist = scrollToPosition - newPos;
+
     qDebug() << "setContentPositionHelper overshoot:"<<overshootPosition<<"delta:"<<deltaPos<<"old:" << oldPos << " new:" << newPos;
 
     QPointF oldClampedPos;
@@ -1034,113 +1038,103 @@ void QKineticScrollerPrivate::setContentPositionHelper(const QPointF &deltaPos)
 
     qreal oldOvershootX = (canOvershootX) ? oldPos.x() - oldClampedPos.x() : 0;
     qreal oldOvershootY = (canOvershootY) ? oldPos.y() - oldClampedPos.y() : 0;
-    if (state == QKineticScroller::StateDragging && overshootDragResistanceFactor) {
-        oldOvershootX /= overshootDragResistanceFactor;
-        oldOvershootY /= overshootDragResistanceFactor;
-    }
 
     qreal newOvershootX = (canOvershootX) ? newPos.x() - newClampedPos.x() : 0;
     qreal newOvershootY = (canOvershootY) ? newPos.y() - newClampedPos.y() : 0;
 
+    if (state == QKineticScroller::StateDragging && overshootDragResistanceFactor) {
+        oldOvershootX *= overshootDragResistanceFactor;
+        oldOvershootY *= overshootDragResistanceFactor;
+        newOvershootX *= overshootDragResistanceFactor;
+        newOvershootY *= overshootDragResistanceFactor;
+    }
+
+    // -- stop at the maximum overshoot distance (if set)
+    if (!overshootMaximumDistance.isNull()) {
+        newOvershootX = qBound(-overshootMaximumDistance.x() * pixelPerMeter, newOvershootX, overshootMaximumDistance.x() * pixelPerMeter);
+
+        newOvershootY = qBound(-overshootMaximumDistance.y() * pixelPerMeter, newOvershootY, overshootMaximumDistance.y() * pixelPerMeter);
+    }
+
     // --- sanity check for scrollTo in case we can't even scroll that direction
     if (!(maxPos.x() || alwaysOvershootX))
         scrollToX = false;
     if (!(maxPos.y() || alwaysOvershootY))
         scrollToY = false;
 
-    QPointF oldScrollToDist = scrollToPosition - oldPos;
-    QPointF newScrollToDist = scrollToPosition - newPos;
-
-    QPointF realOvershootDistance;
-
+    // --- handle crossing over borders (scrollTo and overshoot)
     qDebug() << "oldOver: " << oldOvershootY << "  newOver: " << newOvershootY;
     // -- x axis
     if (scrollToX && qSign(oldScrollToDist.x()) != qSign(newScrollToDist.x())) {
         newClampedPos.setX(scrollToPosition.x());
+        newOvershootX = 0;
         releaseVelocity.setX(0);
         scrollToX = false;
 
     } else if (oldOvershootX && (qSign(oldOvershootX) != qSign(newOvershootX))) {
         newClampedPos.setX((oldOvershootX < 0) ? 0 : maxPos.x());
-        realOvershootDistance.setX(0);
+        newOvershootX = 0;
         releaseVelocity.setX(0);
         overshootVelocity.setX(0);
         overshootX = false;
 
-    } else if (newOvershootX) {
-        if (!oldOvershootX) {
-            overshootStartTimeX = qreal(scrollAbsoluteTimer.elapsed()) / 1000;
-            overshootVelocity.setX(calculateVelocity(overshootStartTimeX).x());
+    } else if (!oldOvershootX && newOvershootX) {
+        overshootStartTimeX = qreal(scrollAbsoluteTimer.elapsed()) / 1000;
+        overshootVelocity.setX(calculateVelocity(overshootStartTimeX).x());
 
-            // restrict the overshoot to overshootMaximumDistance
-            qreal maxOvershootVelocity = overshootMaximumDistance.x() * overshootSpringConstantRoot;
-            if (overshootMaximumDistance.x() && qAbs(overshootVelocity.x()) > maxOvershootVelocity)
-                overshootVelocity.setX(maxOvershootVelocity * qSign(newOvershootX));
+        // restrict the overshoot to overshootMaximumDistance
+        qreal maxOvershootVelocity = overshootMaximumDistance.x() * overshootSpringConstantRoot;
+        if (overshootMaximumDistance.x() && qAbs(overshootVelocity.x()) > maxOvershootVelocity)
+            overshootVelocity.setX(maxOvershootVelocity * qSign(newOvershootX));
 
-            // -- prevent going into overshoot too far
-            if (state != QKineticScroller::StateDragging && overshootDragResistanceFactor)
-                newOvershootX = qSign(newOvershootX) * qreal(0.0001);
+        // -- prevent going into overshoot too far
+        if (state != QKineticScroller::StateDragging)
+            newOvershootX = qSign(newOvershootX) * qreal(0.0001);
 
-            scrollToX = false;
-            overshootX = true;
-        }
-        realOvershootDistance.setX(newOvershootX);
+        scrollToX = false;
+        overshootX = true;
     }
 
     // -- y axis
     if (scrollToY && qSign(oldScrollToDist.y()) != qSign(newScrollToDist.y())) {
         newClampedPos.setY(scrollToPosition.y());
+        newOvershootY = 0;
         releaseVelocity.setY(0);
         scrollToY = false;
 
     } else if (oldOvershootY && (qSign(oldOvershootY) != qSign(newOvershootY))) {
         newClampedPos.setY((oldOvershootY < 0) ? 0 : maxPos.y());
-        realOvershootDistance.setY(0);
+        newOvershootY = 0;
         releaseVelocity.setY(0);
         overshootVelocity.setY(0);
         overshootY = false;
 
-    } else if (newOvershootY) {
-        if (!oldOvershootY) {
-            overshootStartTimeY = qreal(scrollAbsoluteTimer.elapsed()) / 1000;
-            overshootVelocity.setY(calculateVelocity(overshootStartTimeY).y());
+    } else if (!oldOvershootY && newOvershootY) {
+        overshootStartTimeY = qreal(scrollAbsoluteTimer.elapsed()) / 1000;
+        overshootVelocity.setY(calculateVelocity(overshootStartTimeY).y());
 
-            // -- restrict the overshoot to overshootMaximumDistance
-            qreal maxOvershootVelocity = overshootMaximumDistance.y() * overshootSpringConstantRoot;
-            if (overshootMaximumDistance.y() && (qAbs(overshootVelocity.y()) > maxOvershootVelocity))
-                overshootVelocity.setY(maxOvershootVelocity * qSign(newOvershootY));
+        // -- restrict the overshoot to overshootMaximumDistance
+        qreal maxOvershootVelocity = overshootMaximumDistance.y() * overshootSpringConstantRoot;
+        if (overshootMaximumDistance.y() && (qAbs(overshootVelocity.y()) > maxOvershootVelocity))
+            overshootVelocity.setY(maxOvershootVelocity * qSign(newOvershootY));
 
-            // -- prevent going into overshoot too far
-            if (state != QKineticScroller::StateDragging && overshootDragResistanceFactor)
-                newOvershootY = qSign(newOvershootY) * qreal(0.0001);
+        // -- prevent going into overshoot too far
+        if (state != QKineticScroller::StateDragging)
+            newOvershootY = qSign(newOvershootY) * qreal(0.0001);
 
-            scrollToY = false;
-            overshootY = true;
-        }
-        realOvershootDistance.setY(newOvershootY);
+        scrollToY = false;
+        overshootY = true;
     }
 
-    overshootPosition = realOvershootDistance;
-
-    // -- finishing overshoot distance
-    if (!realOvershootDistance.isNull()) {
-        if (state == QKineticScroller::StateDragging)
-            realOvershootDistance *= overshootDragResistanceFactor;
-
-        // -- stop at the maximum overshoot distance (if set)
-        if (!overshootMaximumDistance.isNull()) {
-            realOvershootDistance.setX(qBound(-overshootMaximumDistance.x() * pixelPerMeter, realOvershootDistance.x(), overshootMaximumDistance.x() * pixelPerMeter));
-
-            realOvershootDistance.setY(qBound(-overshootMaximumDistance.y() * pixelPerMeter, realOvershootDistance.y(), overshootMaximumDistance.y() * pixelPerMeter));
-        }
-    }
+    overshootPosition.setX(newOvershootX);
+    overshootPosition.setY(newOvershootY);
 
-    q->setContentPosition(newClampedPos, realOvershootDistance);
+    q->setContentPosition(newClampedPos, overshootPosition);
 
     if (debugHook)
-        debugHook(debugHookUser, calculateVelocity(qreal(scrollAbsoluteTimer.elapsed()) / 1000), newClampedPos, realOvershootDistance);
+        debugHook(debugHookUser, calculateVelocity(qreal(scrollAbsoluteTimer.elapsed()) / 1000), newClampedPos, overshootPosition);
 
-    qDebug() << "setContentPositionHelper" << newClampedPos << " overshoot:" << realOvershootDistance <<
+    qDebug() << "setContentPositionHelper" << newClampedPos << " overshoot:" << overshootPosition<<
     "Overshoot: "<<overshootX<<","<<overshootY<<"ScrollTo:"<<scrollToX<<","<<scrollToY;
 }