plasma: drop the feature of Plasma::ScrollWidget to move on mouse move events

does not do bounds checking like the usual moving, also requires event
filter for DnD in widgets using it to ensure events are not stolen by it

Signed-off-by: Ivailo Monev <xakepa10@gmail.com>

plasma/widgets/scrollwidget.cpp

@@ -51,34 +51,6 @@
 #include <plasma/animator.h>
 #include <plasma/svg.h>
 
-
-#define DEBUG 0
-
-/*
-  The flicking code is largely based on the behavior of
-  the flickable widget in QDeclerative so porting between
-  the two should preserve the behavior.
-  The code that figures out velocity could use some
-  improvements, in particular IGNORE_SUSPICIOUS_MOVES
-  is a hack that shouldn't be necessary.
- */
-
-//XXX fixme
-//    we use a timer between move events to figure out
-//    the velocity of a move, but sometimes we're getting move
-//    events with big positional changes with no break
-//    in between them, which causes us to compute
-//    huge velocities. this define just filters out
-//    events which come at insanly small time intervals.
-//    at some point we need to figure out how to do it properly
-#define IGNORE_SUSPICIOUS_MOVES 1
-
-// FlickThreshold determines how far the "mouse" must have moved
-// before we perform a flick.
-static const int FlickThreshold = 20;
-
-
-static const qreal MinimumFlickVelocity = 200;
 static const qreal MaxVelocity = 2000;
 
 // time it takes the widget to flick back to its
@@ -155,7 +127,6 @@ public:
         fixupAnimation.snapX = 0;
         fixupAnimation.snapY = 0;
         directMoveAnimation = 0;
-        stealEvent = false;
         hasOvershoot = true;
 
         alignment = (Qt::AlignLeft | Qt::AlignTop);
@@ -353,12 +324,12 @@ public:
         // -ve velocity means list is moving up
         if (velocity > 0) {
             if (val < minExtent)
-                maxDistance = qAbs(minExtent - val + (hasOvershoot?overShootDistance(velocity,size):0));
+                maxDistance = qAbs(minExtent - val + (hasOvershoot ? overShootDistance(velocity,size) : 0));
             target = minExtent;
             deceleration = -deceleration;
         } else {
             if (val > maxExtent)
-                maxDistance = qAbs(maxExtent - val) + (hasOvershoot?overShootDistance(velocity,size):0);
+                maxDistance = qAbs(maxExtent - val) + (hasOvershoot ? overShootDistance(velocity,size) : 0);
             target = maxExtent;
         }
         if (maxDistance > 0) {
@@ -384,15 +355,15 @@ public:
             }
             duration = qAbs((endY-startY)/ (-v/2));
 
-#if DEBUG
+#ifndef NDEBUG
-            qDebug()<<"XXX velocity = "<<v <<", target = "<< target
+            qDebug() <<"XXX velocity = "<<v <<", target = "<< target
                      <<", maxDist = "<<maxDistance;
-            qDebug()<<"duration = "<<duration<<" secs, ("
+            qDebug() <<"duration = "<<duration<<" secs, ("
                      << (duration * 1000) <<" msecs)";
-            qDebug()<<"startY = "<<startY;
+            qDebug() <<"startY = "<<startY;
-            qDebug()<<"endY = "<<endY;
+            qDebug() <<"endY = "<<endY;
-            qDebug()<<"overshoot = "<<overShootDistance(v, size);
+            qDebug() <<"overshoot = "<< overShootDistance(v, size);
-            qDebug()<<"avg velocity = "<< ((endY-startY)/duration);
+            qDebug() <<"avg velocity = "<< ((endY-startY)/duration);
 #endif
 
             anim->setStartValue(startY);
@@ -406,16 +377,19 @@ public:
                 fixupY();
         }
     }
+
     void flickX(qreal velocity)
     {
         flick(flickAnimationX, velocity, widget.data()->x(), minXExtent(), maxXExtent(),
               q->viewportGeometry().width());
     }
+
     void flickY(qreal velocity)
     {
         flick(flickAnimationY, velocity, widget.data()->y(),minYExtent(), maxYExtent(),
               q->viewportGeometry().height());
     }
+
     void fixup(QAnimationGroup *group,
                QPropertyAnimation *start, QPropertyAnimation *end,
                qreal val, qreal minExtent, qreal maxExtent)
@@ -591,145 +565,6 @@ public:
         directMoveAnimation->start();
     }
 
-    void handleMousePressEvent(QGraphicsSceneMouseEvent *event)
-    {
-        lastPos = QPoint();
-        lastPosTime.restart();
-        pressPos = event->scenePos();
-        pressScrollPos = -q->scrollPosition();
-        pressTime.restart();
-        velocity = QPointF();
-        stopAnimations();
-    }
-
-    void handleMouseMoveEvent(QGraphicsSceneMouseEvent *event)
-    {
-        if (!lastPosTime.isValid())
-            return;
-        bool rejectY = false;
-        bool rejectX = false;
-
-        if (canYFlick()) {
-            int dy = int(event->scenePos().y() - pressPos.y());
-            if (qAbs(dy) > KGlobalSettings::dndEventDelay() || pressTime.elapsed() > 200) {
-                qreal newY = dy + pressScrollPos.y();
-                const qreal minY = minYExtent();
-                const qreal maxY = maxYExtent();
-                if (newY > minY)
-                    newY = minY + (newY - minY) / 2;
-                if (newY < maxY && maxY - minY <= 0)
-                    newY = maxY + (newY - maxY) / 2;
-                if (!hasOvershoot && (newY > minY || newY < maxY)) {
-                    if (newY > minY)
-                        newY = minY;
-                    else if (newY < maxY)
-                        newY = maxY;
-                    else
-                        rejectY = true;
-                }
-                if (!rejectY && stealEvent) {
-                    widget.data()->setY(qRound(newY));
-                }
-                if (qAbs(dy) > KGlobalSettings::dndEventDelay())
-                    stealEvent = true;
-            }
-        }
-
-        if (canXFlick()) {
-            int dx = int(event->scenePos().x() - pressPos.x());
-            if (qAbs(dx) > KGlobalSettings::dndEventDelay() || pressTime.elapsed() > 200) {
-                qreal newX = dx + pressScrollPos.x();
-                const qreal minX = minXExtent();
-                const qreal maxX = maxXExtent();
-                if (newX > minX)
-                    newX = minX + (newX - minX) / 2;
-                if (newX < maxX && maxX - minX <= 0)
-                    newX = maxX + (newX - maxX) / 2;
-                if (!hasOvershoot && (newX > minX || newX < maxX)) {
-                    if (newX > minX)
-                        newX = minX;
-                    else if (newX < maxX)
-                        newX = maxX;
-                    else
-                        rejectX = true;
-                }
-                if (!rejectX && stealEvent) {
-                    widget.data()->setX(qRound(newX));
-                }
-
-                if (qAbs(dx) > KGlobalSettings::dndEventDelay())
-                    stealEvent = true;
-            }
-        }
-
-        if (!lastPos.isNull()) {
-            qreal msecs = qreal(lastPosTime.restart());
-            qreal elapsed =  msecs / 1000.;
-#if IGNORE_SUSPICIOUS_MOVES
-            if (msecs > 3) {
-#endif
-            if (elapsed <= 0)
-                elapsed = 1;
-            if (canYFlick()) {
-                qreal diff = event->scenePos().y() - lastPos.y();
-                // average to reduce the effect of spurious moves
-                velocity.setY( velocity.y() + (diff / elapsed) );
-                velocity.setY( velocity.y() / 2 );
-            }
-
-            if (canXFlick()) {
-                qreal diff = event->scenePos().x() - lastPos.x();
-                // average to reduce the effect of spurious moves
-                velocity.setX( velocity.x() + (diff / elapsed) );
-                velocity.setX( velocity.x() / 2 );
-            }
-#if IGNORE_SUSPICIOUS_MOVES
-            }
-#endif
-        }
-
-        if (rejectX) velocity.setX(0);
-        if (rejectY) velocity.setY(0);
-
-        lastPos = event->scenePos();
-    }
-
-    void handleMouseReleaseEvent(QGraphicsSceneMouseEvent *event)
-    {
-        stealEvent = false;
-        if (!lastPosTime.isValid())
-            return;
-
-        if (lastPosTime.elapsed() > 100) {
-            // if we drag then pause before release we should not cause a flick.
-            velocity = QPointF();
-        }
-
-        if (qAbs(velocity.y()) > 10 &&
-            qAbs(event->scenePos().y() - pressPos.y()) > FlickThreshold) {
-            qreal vVelocity = velocity.y();
-            // Minimum velocity to avoid annoyingly slow flicks.
-            if (qAbs(vVelocity) < MinimumFlickVelocity)
-                vVelocity = vVelocity < 0 ? -MinimumFlickVelocity : MinimumFlickVelocity;
-            flickY(vVelocity);
-        } else {
-            fixupY();
-        }
-
-        if (qAbs(velocity.x()) > 10 &&
-            qAbs(event->scenePos().x() - pressPos.x()) > FlickThreshold) {
-            qreal hVelocity = velocity.x();
-            // Minimum velocity to avoid annoyingly slow flicks.
-            if (qAbs(hVelocity) < MinimumFlickVelocity)
-                hVelocity = hVelocity < 0 ? -MinimumFlickVelocity : MinimumFlickVelocity;
-            flickX(hVelocity);
-        } else {
-            fixupX();
-        }
-
-        lastPosTime.invalidate();
-    }
-
     void handleWheelEvent(QGraphicsSceneWheelEvent *event)
     {
         //only scroll when the animation is done, this avoids to receive too many events and getting mad when they arrive from a touchpad
@@ -783,50 +618,46 @@ public:
 
     qreal minXExtent() const
     {
-        if (alignment & Qt::AlignLeft)
+        if (alignment & Qt::AlignLeft) {
             return 0;
-        else {
+        }
         qreal vWidth = q->viewportGeometry().width();
         qreal cWidth = q->contentsSize().width();
         if (cWidth < vWidth) {
-                if (alignment & Qt::AlignRight)
+            if (alignment & Qt::AlignRight) {
                 return  vWidth - cWidth;
-                else if (alignment & Qt::AlignHCenter)
+            } else if (alignment & Qt::AlignHCenter) {
                 return vWidth / 2 - cWidth / 2;
             }
         }
-
         return 0;
     }
 
     qreal maxXExtent() const
     {
-        return q->viewportGeometry().width() -
+        return q->viewportGeometry().width() - q->contentsSize().width();
-            q->contentsSize().width();
     }
 
     qreal minYExtent() const
     {
-        if (alignment & Qt::AlignTop)
+        if (alignment & Qt::AlignTop) {
             return 0;
-        else {
+        }
         qreal vHeight = q->viewportGeometry().height();
         qreal cHeight = q->contentsSize().height();
         if (cHeight < vHeight) {
-                if (alignment & Qt::AlignBottom)
+            if (alignment & Qt::AlignBottom) {
                 return  vHeight - cHeight;
-                else if (alignment & Qt::AlignVCenter)
+            } else if (alignment & Qt::AlignVCenter) {
                 return vHeight / 2 - cHeight / 2;
             }
         }
-
         return 0;
     }
 
     qreal maxYExtent() const
     {
-        return q->viewportGeometry().height() -
+        return q->viewportGeometry().height() - q->contentsSize().height();
-            q->contentsSize().height();
     }
 
     bool canXFlick() const
@@ -978,12 +809,6 @@ public:
     QRectF rectToBeVisible;
     QTimer *wheelTimer;
 
-    QPointF pressPos;
-    QPointF pressScrollPos;
-    QPointF velocity;
-    QPointF lastPos;
-    QElapsedTimer pressTime;
-    QElapsedTimer lastPosTime;
     QPropertyAnimation *flickAnimationX;
     QPropertyAnimation *flickAnimationY;
     struct {
@@ -1000,7 +825,6 @@ public:
     } fixupAnimation;
     QPropertyAnimation *directMoveAnimation;
     QSizeF snapSize;
-    bool stealEvent;
     bool hasOvershoot;
     bool overflowBordersVisible;
 
@@ -1055,7 +879,6 @@ QGraphicsWidget *ScrollWidget::widget() const
     return d->widget.data();
 }
 
-
 void ScrollWidget::setHorizontalScrollBarPolicy(const Qt::ScrollBarPolicy policy)
 {
     d->horizontalScrollBarPolicy = policy;
@@ -1130,8 +953,6 @@ void ScrollWidget::ensureItemVisible(QGraphicsItem *item)
     }
 }
 
-
-
 QRectF ScrollWidget::viewportGeometry() const
 {
     QRectF result;
@@ -1182,7 +1003,6 @@ void ScrollWidget::focusInEvent(QFocusEvent *event)
     }
 }
 
-
 void ScrollWidget::resizeEvent(QGraphicsSceneResizeEvent *event)
 {
     if (!d->widget) {
@@ -1212,46 +1032,6 @@ void ScrollWidget::keyPressEvent(QKeyEvent *event)
     d->handleKeyPressEvent(event);
 }
 
-void ScrollWidget::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
-{
-    if (!d->widget) {
-        return;
-    }
-
-    d->handleMouseMoveEvent(event);
-    event->accept();
-
-    return QGraphicsWidget::mouseMoveEvent(event);
-}
-
-void ScrollWidget::mousePressEvent(QGraphicsSceneMouseEvent *event)
-{
-    if (!d->widget) {
-        return;
-    } else if (!d->canYFlick() && !d->canXFlick()) {
-        event->ignore();
-        return;
-    }
-
-    d->handleMousePressEvent(event);
-
-    if (event->button() == Qt::LeftButton) {
-        event->accept();
-    } else {
-        QGraphicsWidget::mousePressEvent(event);
-    }
-}
-
-void ScrollWidget::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
-{
-    if (!d->widget) {
-        return;
-    }
-
-    d->handleMouseReleaseEvent(event);
-    event->accept();
-}
-
 void ScrollWidget::wheelEvent(QGraphicsSceneWheelEvent *event)
 {
     if (!d->widget) {
@@ -1326,63 +1106,6 @@ QSizeF ScrollWidget::sizeHint(Qt::SizeHint which, const QSizeF & constraint) con
     return hint;
 }
 
-
-bool ScrollWidget::sceneEventFilter(QGraphicsItem *i, QEvent *e)
-{
-    //only the scrolling widget and its children
-    if (!d->widget.data() ||
-        (!d->scrollingWidget->isAncestorOf(i) && i != d->scrollingWidget) ||
-        i == d->horizontalScrollBar || i == d->verticalScrollBar) {
-        return false;
-    }
-
-    if (i->isWidget()) {
-        Plasma::Label *label = dynamic_cast<Plasma::Label *>(static_cast<QGraphicsWidget *>(i));
-        if (label && (label->nativeWidget()->textInteractionFlags() & Qt::TextSelectableByMouse)) {
-            return false;
-        }
-
-        Plasma::TextEdit *textEdit = dynamic_cast<Plasma::TextEdit *>(static_cast<QGraphicsWidget *>(i));
-        if (textEdit && (textEdit->nativeWidget()->textInteractionFlags() & Qt::TextSelectableByMouse)) {
-            return false;
-        }
-
-        Plasma::TextBrowser *textBrowser= dynamic_cast<Plasma::TextBrowser *>(static_cast<QGraphicsWidget *>(i));
-        if (textBrowser && (textBrowser->nativeWidget()->textInteractionFlags() & Qt::TextSelectableByMouse)) {
-            return false;
-        }
-    }
-
-    bool stealThisEvent = d->stealEvent;
-    //still pass around mouse moves: try to make still possible to make items start a drag event. thi could be either necessary or annoying, let's see how it goes. (add QEvent::GraphicsSceneMouseMove to block them)
-    stealThisEvent &= (e->type() == QEvent::GraphicsSceneMousePress ||
-                       e->type() == QEvent::GraphicsSceneMouseRelease);
-#if DEBUG
-    qDebug() << "sceneEventFilter = " << i <<", "
-             << QTime::currentTime().toString(QString::fromLatin1("hh:mm:ss.zzz"));
-#endif
-    switch (e->type()) {
-        case QEvent::GraphicsSceneMousePress: {
-            d->handleMousePressEvent(static_cast<QGraphicsSceneMouseEvent*>(e));
-            break;
-        }
-        case QEvent::GraphicsSceneMouseMove: {
-            d->handleMouseMoveEvent(static_cast<QGraphicsSceneMouseEvent*>(e));
-            break;
-        }
-        case QEvent::GraphicsSceneMouseRelease: {
-            d->handleMouseReleaseEvent(static_cast<QGraphicsSceneMouseEvent*>(e));
-            break;
-        }
-        default: {
-            break;
-        }
-    }
-    if (stealThisEvent)
-        return true;
-    return QGraphicsWidget::sceneEventFilter(i, e);
-}
-
 void Plasma::ScrollWidget::setAlignment(Qt::Alignment align)
 {
     d->alignment = align;

plasma/widgets/scrollwidget.h

@@ -221,15 +221,11 @@ Q_SIGNALS:
 
 protected:
     void resizeEvent(QGraphicsSceneResizeEvent *event);
-    void mouseMoveEvent(QGraphicsSceneMouseEvent *event);
-    void mousePressEvent(QGraphicsSceneMouseEvent *event);
-    void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);
     void keyPressEvent(QKeyEvent *event);
     void wheelEvent(QGraphicsSceneWheelEvent *event);
     bool eventFilter(QObject *watched, QEvent *event);
     void focusInEvent(QFocusEvent *event);
     QSizeF sizeHint(Qt::SizeHint which, const QSizeF & constraint) const;
-    bool sceneEventFilter(QGraphicsItem *i, QEvent *e);
 
 private:
     ScrollWidgetPrivate * const d;