Mac: refactor scrollbar animations

Get rid of QWidget-centric QMacStyle::eventFilter() and implement the
fade out animations for scrollbars using QNumberStyleAnimation-based
QFadeOutAnimation.

Change-Id: I2000fa50d46b153e981ceafc12a53932a196382e
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>

8 files changed, 170 insertions, 24 deletions

diff --git a/src/widgets/widgets/qabstractscrollarea.cpp b/src/widgets/widgets/qabstractscrollarea.cpp
index 8aa5534366..3c21d767be 100644
--- a/src/widgets/widgets/qabstractscrollarea.cpp
+++ b/src/widgets/widgets/qabstractscrollarea.cpp
@@ -57,6 +57,7 @@
 #include <QDebug>
 
 #include "qabstractscrollarea_p.h"
+#include "qscrollbar_p.h"
 #include <qwidget.h>
 
 #include <private/qapplication_p.h>
@@ -183,6 +184,7 @@ QAbstractScrollAreaScrollBarContainer::QAbstractScrollAreaScrollBarContainer(Qt:
     layout->setMargin(0);
     layout->setSpacing(0);
     layout->addWidget(scrollBar);
+    layout->setSizeConstraint(QLayout::SetMaximumSize);
 }
 
 /*! \internal
@@ -266,6 +268,8 @@ void QAbstractScrollAreaPrivate::replaceScrollBar(QScrollBar *scrollBar,
     scrollBar->setSliderPosition(oldBar->sliderPosition());
     scrollBar->setTracking(oldBar->hasTracking());
     scrollBar->setValue(oldBar->value());
+    scrollBar->installEventFilter(q);
+    oldBar->removeEventFilter(q);
     delete oldBar;
 
     QObject::connect(scrollBar, SIGNAL(valueChanged(int)),
@@ -286,6 +290,7 @@ void QAbstractScrollAreaPrivate::init()
     hbar = scrollBarContainers[Qt::Horizontal]->scrollBar;
     hbar->setRange(0,0);
     scrollBarContainers[Qt::Horizontal]->setVisible(false);
+    hbar->installEventFilter(q);
     QObject::connect(hbar, SIGNAL(valueChanged(int)), q, SLOT(_q_hslide(int)));
     QObject::connect(hbar, SIGNAL(rangeChanged(int,int)), q, SLOT(_q_showOrHideScrollBars()), Qt::QueuedConnection);
     scrollBarContainers[Qt::Vertical] = new QAbstractScrollAreaScrollBarContainer(Qt::Vertical, q);
@@ -293,6 +298,7 @@ void QAbstractScrollAreaPrivate::init()
     vbar = scrollBarContainers[Qt::Vertical]->scrollBar;
     vbar->setRange(0,0);
     scrollBarContainers[Qt::Vertical]->setVisible(false);
+    vbar->installEventFilter(q);
     QObject::connect(vbar, SIGNAL(valueChanged(int)), q, SLOT(_q_vslide(int)));
     QObject::connect(vbar, SIGNAL(rangeChanged(int,int)), q, SLOT(_q_showOrHideScrollBars()), Qt::QueuedConnection);
     viewportFilter.reset(new QAbstractScrollAreaFilter(this));
@@ -323,10 +329,10 @@ void QAbstractScrollAreaPrivate::layoutChildren()
 {
     Q_Q(QAbstractScrollArea);
     bool needh = (hbarpolicy == Qt::ScrollBarAlwaysOn
-                  || (hbarpolicy == Qt::ScrollBarAsNeeded && hbar->minimum() < hbar->maximum()));
+                  || (hbarpolicy == Qt::ScrollBarAsNeeded && hbar->minimum() < hbar->maximum() && !hbar->sizeHint().isEmpty()));
 
     bool needv = (vbarpolicy == Qt::ScrollBarAlwaysOn
-                  || (vbarpolicy == Qt::ScrollBarAsNeeded && vbar->minimum() < vbar->maximum()));
+                  || (vbarpolicy == Qt::ScrollBarAsNeeded && vbar->minimum() < vbar->maximum() && !vbar->sizeHint().isEmpty()));
 
     QStyleOption opt(0);
     opt.init(q);
@@ -648,6 +654,7 @@ void QAbstractScrollArea::setVerticalScrollBarPolicy(Qt::ScrollBarPolicy policy)
         d->layoutChildren();
     if (oldPolicy != d->vbarpolicy)
         d->scrollBarPolicyChanged(Qt::Vertical, d->vbarpolicy);
+    d->setScrollBarTransient(d->vbar, policy == Qt::ScrollBarAsNeeded);
 }
 
 
@@ -709,6 +716,7 @@ void QAbstractScrollArea::setHorizontalScrollBarPolicy(Qt::ScrollBarPolicy polic
         d->layoutChildren();
     if (oldPolicy != d->hbarpolicy)
         d->scrollBarPolicyChanged(Qt::Horizontal, d->hbarpolicy);
+    d->setScrollBarTransient(d->hbar, policy == Qt::ScrollBarAsNeeded);
 }
 
 /*!
@@ -921,6 +929,20 @@ void QAbstractScrollArea::setViewportMargins(const QMargins &margins)
                        margins.right(), margins.bottom());
 }
 
+/*! \internal */
+bool QAbstractScrollArea::eventFilter(QObject *o, QEvent *e)
+{
+    Q_D(QAbstractScrollArea);
+    if ((o == d->hbar || o == d->vbar) && (e->type() == QEvent::HoverEnter || e->type() == QEvent::HoverLeave)) {
+        Qt::ScrollBarPolicy policy = o == d->hbar ? d->vbarpolicy : d->hbarpolicy;
+        if (policy == Qt::ScrollBarAsNeeded) {
+            QScrollBar *sibling = o == d->hbar ? d->vbar : d->hbar;
+            d->setScrollBarTransient(sibling, e->type() == QEvent::HoverLeave);
+        }
+    }
+    return QFrame::eventFilter(o, e);
+}
+
 /*!
     \fn bool QAbstractScrollArea::event(QEvent *event)
 
@@ -1421,12 +1443,26 @@ bool QAbstractScrollAreaPrivate::canStartScrollingAt( const QPoint &startPos )
     return true;
 }
 
+void QAbstractScrollAreaPrivate::flashScrollBars()
+{
+    if (hbarpolicy == Qt::ScrollBarAsNeeded)
+        hbar->d_func()->flash();
+    if (vbarpolicy == Qt::ScrollBarAsNeeded)
+        vbar->d_func()->flash();
+}
+
+void QAbstractScrollAreaPrivate::setScrollBarTransient(QScrollBar *scrollBar, bool transient)
+{
+    scrollBar->d_func()->setTransient(transient);
+}
+
 void QAbstractScrollAreaPrivate::_q_hslide(int x)
 {
     Q_Q(QAbstractScrollArea);
     int dx = xoffset - x;
     xoffset = x;
     q->scrollContentsBy(dx, 0);
+    flashScrollBars();
 }
 
 void QAbstractScrollAreaPrivate::_q_vslide(int y)
@@ -1435,6 +1471,7 @@ void QAbstractScrollAreaPrivate::_q_vslide(int y)
     int dy = yoffset - y;
     yoffset = y;
     q->scrollContentsBy(0, dy);
+    flashScrollBars();
 }
 
 void QAbstractScrollAreaPrivate::_q_showOrHideScrollBars()
diff --git a/src/widgets/widgets/qabstractscrollarea.h b/src/widgets/widgets/qabstractscrollarea.h
index 560df9dcae..5ac140241e 100644
--- a/src/widgets/widgets/qabstractscrollarea.h
+++ b/src/widgets/widgets/qabstractscrollarea.h
@@ -96,6 +96,7 @@ protected:
     void setViewportMargins(int left, int top, int right, int bottom);
     void setViewportMargins(const QMargins &margins);
 
+    bool eventFilter(QObject *, QEvent *);
     bool event(QEvent *);
     virtual bool viewportEvent(QEvent *);
 
diff --git a/src/widgets/widgets/qabstractscrollarea_p.h b/src/widgets/widgets/qabstractscrollarea_p.h
index d77d97e03f..7e2ca741b1 100644
--- a/src/widgets/widgets/qabstractscrollarea_p.h
+++ b/src/widgets/widgets/qabstractscrollarea_p.h
@@ -92,6 +92,9 @@ public:
     virtual void scrollBarPolicyChanged(Qt::Orientation, Qt::ScrollBarPolicy) {}
     bool canStartScrollingAt( const QPoint &startPos );
 
+    void flashScrollBars();
+    void setScrollBarTransient(QScrollBar *scrollBar, bool transient);
+
     void _q_hslide(int);
     void _q_vslide(int);
     void _q_showOrHideScrollBars();
diff --git a/src/widgets/widgets/qscrollarea.cpp b/src/widgets/widgets/qscrollarea.cpp
index be7ce10c8c..576f77a7b7 100644
--- a/src/widgets/widgets/qscrollarea.cpp
+++ b/src/widgets/widgets/qscrollarea.cpp
@@ -331,7 +331,7 @@ bool QScrollArea::eventFilter(QObject *o, QEvent *e)
     if (o == d->widget && e->type() == QEvent::Resize)
         d->updateScrollBars();
 
-    return false;
+    return QAbstractScrollArea::eventFilter(o, e);
 }
 
 /*!
diff --git a/src/widgets/widgets/qscrollbar.cpp b/src/widgets/widgets/qscrollbar.cpp
index aa45b4f54e..199aaf93de 100644
--- a/src/widgets/widgets/qscrollbar.cpp
+++ b/src/widgets/widgets/qscrollbar.cpp
@@ -55,7 +55,7 @@
 #include "qaccessible.h"
 #endif
 #include <limits.h>
-#include "qabstractslider_p.h"
+#include "qscrollbar_p.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -201,26 +201,6 @@ QT_BEGIN_NAMESPACE
     \sa QScrollArea, QSlider, QDial, QSpinBox, {fowler}{GUI Design Handbook: Scroll Bar}, {Sliders Example}
 */
 
-class QScrollBarPrivate : public QAbstractSliderPrivate
-{
-    Q_DECLARE_PUBLIC(QScrollBar)
-public:
-    QStyle::SubControl pressedControl;
-    bool pointerOutsidePressedControl;
-
-    int clickOffset, snapBackPosition;
-
-    void activateControl(uint control, int threshold = 500);
-    void stopRepeatAction();
-    int pixelPosToRangeValue(int pos) const;
-    void init();
-    bool updateHoverControl(const QPoint &pos);
-    QStyle::SubControl newHoverControl(const QPoint &pos);
-
-    QStyle::SubControl hoverControl;
-    QRect hoverRect;
-};
-
 bool QScrollBarPrivate::updateHoverControl(const QPoint &pos)
 {
     Q_Q(QScrollBar);
@@ -249,6 +229,29 @@ QStyle::SubControl QScrollBarPrivate::newHoverControl(const QPoint &pos)
     return hoverControl;
 }
 
+void QScrollBarPrivate::setTransient(bool value)
+{
+    Q_Q(QScrollBar);
+    if (transient != value) {
+        transient = value;
+        if (transient) {
+            if (q->isVisible() && q->style()->styleHint(QStyle::SH_ScrollBar_Transient))
+                q->update();
+        } else if (!q->isVisible()) {
+            q->show();
+        }
+    }
+}
+
+void QScrollBarPrivate::flash()
+{
+    Q_Q(QScrollBar);
+    if (!flashed && q->style()->styleHint(QStyle::SH_ScrollBar_Transient)) {
+        flashed = true;
+        q->show();
+    }
+}
+
 void QScrollBarPrivate::activateControl(uint control, int threshold)
 {
     QAbstractSlider::SliderAction action = QAbstractSlider::SliderNoAction;
@@ -322,6 +325,8 @@ void QScrollBar::initStyleOption(QStyleOptionSlider *option) const
     option->upsideDown = d->invertedAppearance;
     if (d->orientation == Qt::Horizontal)
         option->state |= QStyle::State_Horizontal;
+    if (d->flashed || !d->transient)
+        option->state |= QStyle::State_On;
 }
 
 
@@ -379,6 +384,8 @@ void QScrollBarPrivate::init()
     invertedControls = true;
     pressedControl = hoverControl = QStyle::SC_None;
     pointerOutsidePressedControl = false;
+    transient = q->style()->styleHint(QStyle::SH_ScrollBar_Transient);
+    flashed = false;
     q->setFocusPolicy(Qt::NoFocus);
     QSizePolicy sp(QSizePolicy::Minimum, QSizePolicy::Fixed, QSizePolicy::Slider);
     if (orientation == Qt::Vertical)
@@ -476,6 +483,9 @@ bool QScrollBar::event(QEvent *event)
     if (const QHoverEvent *he = static_cast<const QHoverEvent *>(event))
         d_func()->updateHoverControl(he->pos());
         break;
+    case QEvent::StyleChange:
+        d_func()->setTransient(style()->styleHint(QStyle::SH_ScrollBar_Transient));
+        break;
     default:
         break;
     }
@@ -521,6 +531,10 @@ void QScrollBar::paintEvent(QPaintEvent *)
         opt.activeSubControls = (QStyle::SubControl)d->hoverControl;
     }
     style()->drawComplexControl(QStyle::CC_ScrollBar, &opt, &p, this);
+    if (d->flashed && style()->styleHint(QStyle::SH_ScrollBar_Transient)) {
+        d->flashed = false;
+        update();
+    }
 }
 
 /*!
diff --git a/src/widgets/widgets/qscrollbar.h b/src/widgets/widgets/qscrollbar.h
index 48863616ff..3e9ac8a47f 100644
--- a/src/widgets/widgets/qscrollbar.h
+++ b/src/widgets/widgets/qscrollbar.h
@@ -83,6 +83,7 @@ protected:
 
 
 private:
+    friend class QAbstractScrollAreaPrivate;
     friend Q_WIDGETS_EXPORT QStyleOptionSlider qt_qscrollbarStyleOption(QScrollBar *scrollBar);
 
     Q_DISABLE_COPY(QScrollBar)
diff --git a/src/widgets/widgets/qscrollbar_p.h b/src/widgets/widgets/qscrollbar_p.h
new file mode 100644
index 0000000000..fb4f5b07da
--- /dev/null
+++ b/src/widgets/widgets/qscrollbar_p.h
@@ -0,0 +1,89 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QSCROLLBAR_P_H
+#define QSCROLLBAR_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include "private/qabstractslider_p.h"
+#include "qstyle.h"
+
+QT_BEGIN_NAMESPACE
+
+class QScrollBarPrivate : public QAbstractSliderPrivate
+{
+    Q_DECLARE_PUBLIC(QScrollBar)
+public:
+    QStyle::SubControl pressedControl;
+    bool pointerOutsidePressedControl;
+
+    int clickOffset, snapBackPosition;
+
+    void activateControl(uint control, int threshold = 500);
+    void stopRepeatAction();
+    int pixelPosToRangeValue(int pos) const;
+    void init();
+    bool updateHoverControl(const QPoint &pos);
+    QStyle::SubControl newHoverControl(const QPoint &pos);
+
+    QStyle::SubControl hoverControl;
+    QRect hoverRect;
+
+    bool transient;
+    void setTransient(bool value);
+
+    bool flashed;
+    void flash();
+};
+
+QT_END_NAMESPACE
+
+#endif // QSCROLLBAR_P_H
diff --git a/src/widgets/widgets/widgets.pri b/src/widgets/widgets/widgets.pri
index c86bc1eff7..797f3e9b76 100644
--- a/src/widgets/widgets/widgets.pri
+++ b/src/widgets/widgets/widgets.pri
@@ -46,6 +46,7 @@ HEADERS += \
         widgets/qradiobutton.h \
         widgets/qrubberband.h \
         widgets/qscrollbar.h \
+        widgets/qscrollbar_p.h \
         widgets/qscrollarea_p.h \
         widgets/qsizegrip.h \
         widgets/qslider.h \