[patch] Smooth scrolling patch.

smooth-scrolling.diff (text/plain), 5.57 KB, created by Simon Strandman on 2005-05-09 09:07:26 UTC

--- khtml/khtmlview.cpp.sav	2005-03-14 10:53:55.116596234 +0100
+++ khtml/khtmlview.cpp	2005-03-14 11:00:50.210653569 +0100
@@ -146,6 +146,9 @@ public:
 
     KHTMLViewPrivate()
         : underMouse( 0 ), underMouseNonShared( 0 )
+#ifndef NO_SMOOTH_SCROLL_HACK
+          , dx(0), dy(0), ddx(0), ddy(0), rdx(0), rdy(0), scrolling(false)
+#endif
     {
 #ifndef KHTML_NO_CARET
 	m_caretViewContext = 0;
@@ -381,6 +384,17 @@ public:
     int m_mouseScroll_byY : 4;
     QTimer *m_mouseScrollTimer;
     QWidget *m_mouseScrollIndicator;
+#ifndef NO_SMOOTH_SCROLL_HACK
+    QTimer timer2;
+    int dx;
+    int dy;
+    // Step size * 16 and residual to avoid huge difference between 1px/step and 2px/step
+    int ddx;
+    int ddy;
+    int rdx;
+    int rdy;
+    bool scrolling;
+#endif
 };
 
 #ifndef QT_NO_TOOLTIP
@@ -489,6 +503,11 @@ KHTMLView::KHTMLView( KHTMLPart *part, Q
     init();
 
     viewport()->show();
+#ifndef NO_SMOOTH_SCROLL_HACK
+#define timer timer2
+    connect(&d->timer, SIGNAL(timeout()), this, SLOT(scrollTick()));
+#undef timer
+#endif
 }
 
 KHTMLView::~KHTMLView()
@@ -1657,8 +1676,16 @@ void KHTMLView::keyReleaseEvent(QKeyEven
         d->scrollSuspendPreActivate = false;
     if( _ke->key() == Key_Shift && d->scrollSuspendPreActivate && _ke->state() == Qt::ShiftButton
         && !(KApplication::keyboardMouseState() & Qt::ShiftButton))
+    {
         if (d->scrollTimerId)
-                d->scrollSuspended = !d->scrollSuspended;
+        {
+            d->scrollSuspended = !d->scrollSuspended;
+#ifndef NO_SMOOTH_SCROLL_HACK
+            if( d->scrollSuspended )
+                stopScrolling();
+#endif
+        }
+    }
 
     // Send keyup event
     if ( dispatchKeyEvent( _ke ) )
@@ -2797,7 +2824,11 @@ void KHTMLView::viewportWheelEvent(QWhee
     else
     {
         d->scrollBarMoved = true;
+#ifndef NO_SMOOTH_SCROLL_HACK
+        scrollViewWheelEvent( e );
+#else
         QScrollView::viewportWheelEvent( e );
+#endif
 
         QMouseEvent *tempEvent = new QMouseEvent( QEvent::MouseMove, QPoint(-1,-1), QPoint(-1,-1), Qt::NoButton, e->state() );
         emit viewportMouseMoveEvent ( tempEvent );
@@ -3986,4 +4017,109 @@ void KHTMLView::moveCaretToLineEnd()
 
 #endif // KHTML_NO_CARET
 
+#ifndef NO_SMOOTH_SCROLL_HACK
+#define timer timer2
+
+// All scrolls must be completed within 240ms of last keypress
+static const int SCROLL_TIME = 240;
+// Each step is 20 ms == 50 frames/second
+static const int SCROLL_TICK = 20;
+
+void KHTMLView::scrollBy(int dx, int dy)
+{
+    KConfigGroup cfg( KGlobal::config(), "KDE" );
+    if( !cfg.readBoolEntry( "SmoothScrolling", true )) {
+        QScrollView::scrollBy( dx, dy );
+        return;
+    }
+    // scrolling destination
+    int full_dx = d->dx + dx;
+    int full_dy = d->dy + dy;
+
+    // scrolling speed
+    int ddx = 0;
+    int ddy = 0;
+
+    int steps = SCROLL_TIME/SCROLL_TICK;
+
+    ddx = (full_dx*16)/steps;
+    ddy = (full_dy*16)/steps;
+
+    // don't go under 1px/step
+    if (ddx > 0 && ddx < 16) ddx = 16;
+    if (ddy > 0 && ddy < 16) ddy = 16;
+    if (ddx < 0 && ddx > -16) ddx = -16;
+    if (ddy < 0 && ddy > -16) ddy = -16;
+
+    d->dx = full_dx;
+    d->dy = full_dy;
+    d->ddx = ddx;
+    d->ddy = ddy;
+
+    if (!d->scrolling) {
+        scrollTick();
+        startScrolling();
+    }
+}
+
+void KHTMLView::scrollTick() {
+    if (d->dx == 0 && d->dy == 0) {
+        stopScrolling();
+        return;
+    }
+
+    int tddx = d->ddx + d->rdx;
+    int tddy = d->ddy + d->rdy;
+
+    int ddx = tddx / 16;
+    int ddy = tddy / 16;
+    d->rdx = tddx % 16;
+    d->rdy = tddy % 16;
+
+    if (d->dx > 0 && ddx > d->dx) ddx = d->dx;
+    else
+    if (d->dx < 0 && ddx < d->dx) ddx = d->dx;
+
+    if (d->dy > 0 && ddy > d->dy) ddy = d->dy;
+    else
+    if (d->dy < 0 && ddy < d->dy) ddy = d->dy;
+
+    d->dx -= ddx;
+    d->dy -= ddy;
+
+//    QScrollView::setContentsPos( contentsX() + ddx, contentsY() + ddy);
+    QScrollView::scrollBy(ddx, ddy);
+}
+
+void KHTMLView::startScrolling()
+{
+    d->scrolling = true;
+    d->timer.start(SCROLL_TICK, false);
+}
+
+void KHTMLView::stopScrolling()
+{
+    d->timer.stop();
+    d->dx = d->dy = 0;
+    d->scrolling = false;
+}
+
+// Overloaded from QScrollView and QScrollBar
+void KHTMLView::scrollViewWheelEvent( QWheelEvent *e )
+{
+    int pageStep = verticalScrollBar()->pageStep();
+    int lineStep = verticalScrollBar()->lineStep();
+    int step = QMIN( QApplication::wheelScrollLines()*lineStep, pageStep );
+    if ( ( e->state() & ControlButton ) || ( e->state() & ShiftButton ) )
+        step = pageStep;
+
+    int dy = (e->delta()*step)/120;
+    scrollBy(0,-dy);
+    e->accept();
+}
+
+#undef timer
+
+#endif // NO_SMOOTH_SCROLL_HACK
+
 #undef DEBUG_CARETMODE
--- khtml/khtmlview.h.sav	2005-03-14 10:53:53.502840927 +0100
+++ khtml/khtmlview.h	2005-03-14 10:54:04.049241779 +0100
@@ -175,6 +175,11 @@ signals:
     void zoomView( int );
     void hideAccessKeys();
     void repaintAccessKeys();
+//#define NO_SMOOTH_SCROLL_HACK
+#ifndef NO_SMOOTH_SCROLL_HACK
+public slots:
+    void scrollBy(int dx, int dy);
+#endif
 
 protected:
     void clear();
@@ -206,9 +211,22 @@ protected:
     void doAutoScroll();
     void timerEvent ( QTimerEvent * );
 
+#ifndef NO_SMOOTH_SCROLL_HACK
+    void startScrolling();
+    void stopScrolling();
+#ifndef QT_NO_WHEELEVENT
+    void scrollViewWheelEvent( QWheelEvent* e );
+#endif
+#endif
+
 protected slots:
     void slotPaletteChanged();
     void slotScrollBarMoved();
+#ifndef NO_SMOOTH_SCROLL_HACK
+    void scrollTick();
+#else
+    void scrollTick() {}; // moc cannot handle #if
+#endif
 
 private slots:
     void tripleClickTimeout();