Extend QStyle API with a SH_Splitter_OpaqueResize styleHint

Currently the default for QSplitter::opaqueResize is hard coded,
which is less than ideal. Instead this should be provided as a
style hint via QStyle so as to give a more uniform look to all
applications.

Change-Id: I5711811f7b672e36aafcd292ed320308570a0390
Reviewed-by: Kevin Ottens <kevin.ottens@kdab.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>

src/widgets/styles/qcommonstyle.cpp

@@ -5124,6 +5124,9 @@ int QCommonStyle::styleHint(StyleHint sh, const QStyleOption *opt, const QWidget
             ret = true;
         }
         break;
+    case SH_Splitter_OpaqueResize:
+        ret = true;
+        break;
     default:
         ret = 0;
         break;

src/widgets/styles/qstyle.cpp

@@ -1904,6 +1904,9 @@ void QStyle::drawItemPixmap(QPainter *painter, const QRect &rect, int alignment,
            a transition between checked and unchecked statuses in a checkbox.
            This enum value has been introduced in Qt 5.2.
 
+    \value SH_Splitter_OpaqueResize Determines if resizing is opaque
+           This enum value has been introduced in Qt 5.2
+
     \sa styleHint()
 */
 

src/widgets/styles/qstyle.h

@@ -701,6 +701,7 @@ public:
         SH_ToolTip_WakeUpDelay,
         SH_ToolTip_FallAsleepDelay,
         SH_Widget_Animate,
+        SH_Splitter_OpaqueResize,
         // Add new style hint values here
 
         SH_CustomBase = 0xf0000000

src/widgets/widgets/qsplitter.cpp

@@ -1404,19 +1404,24 @@ int QSplitter::closestLegalPosition(int pos, int index)
     \property QSplitter::opaqueResize
     \brief whether resizing is opaque
 
-    Opaque resizing is on by default.
+    The default resize behavior is style dependent (determined by the
+    SH_Splitter_OpaqueResize style hint). However, you can override it
+    by calling setOpaqueResize()
+
+    \sa QStyle::StyleHint
 */
 
 bool QSplitter::opaqueResize() const
 {
     Q_D(const QSplitter);
-    return d->opaque;
+    return d->opaqueResizeSet ? d->opaque : style()->styleHint(QStyle::SH_Splitter_OpaqueResize, 0, this);
 }
 
 
 void QSplitter::setOpaqueResize(bool on)
 {
     Q_D(QSplitter);
+    d->opaqueResizeSet = true;
     d->opaque = on;
 }
 
@@ -1589,7 +1594,7 @@ static const qint32 SplitterMagic = 0xff;
 QByteArray QSplitter::saveState() const
 {
     Q_D(const QSplitter);
-    int version = 0;
+    int version = 1;
     QByteArray data;
     QDataStream stream(&data, QIODevice::WriteOnly);
 
@@ -1605,6 +1610,7 @@ QByteArray QSplitter::saveState() const
     stream << qint32(handleWidth());
     stream << opaqueResize();
     stream << qint32(orientation());
+    stream << d->opaqueResizeSet;
     return data;
 }
 
@@ -1627,7 +1633,7 @@ QByteArray QSplitter::saveState() const
 bool QSplitter::restoreState(const QByteArray &state)
 {
     Q_D(QSplitter);
-    int version = 0;
+    int version = 1;
     QByteArray sd = state;
     QDataStream stream(&sd, QIODevice::ReadOnly);
     QList<int> list;
@@ -1638,7 +1644,7 @@ bool QSplitter::restoreState(const QByteArray &state)
 
     stream >> marker;
     stream >> v;
-    if (marker != SplitterMagic || v != version)
+    if (marker != SplitterMagic || v > version)
         return false;
 
     stream >> list;
@@ -1657,6 +1663,9 @@ bool QSplitter::restoreState(const QByteArray &state)
     setOrientation(Qt::Orientation(i));
     d->doResize();
 
+    if (v >= 1)
+        stream >> d->opaqueResizeSet;
+
     return true;
 }
 

src/widgets/widgets/qsplitter_p.h

@@ -83,7 +83,7 @@ class QSplitterPrivate : public QFramePrivate
     Q_DECLARE_PUBLIC(QSplitter)
 public:
     QSplitterPrivate() : rubberBand(0), opaque(true), firstShow(true),
-                         childrenCollapsible(true), compatMode(false), handleWidth(-1), blockChildAdd(false) {}
+                         childrenCollapsible(true), compatMode(false), handleWidth(-1), blockChildAdd(false), opaqueResizeSet(false) {}
 
     QPointer<QRubberBand> rubberBand;
     mutable QList<QSplitterLayoutStruct *> list;
@@ -94,6 +94,7 @@ public:
     bool compatMode : 8;
     int handleWidth;
     bool blockChildAdd;
+    bool opaqueResizeSet;
 
     inline int pick(const QPoint &pos) const
     { return orient == Qt::Horizontal ? pos.x() : pos.y(); }

tests/auto/widgets/widgets/qsplitter/tst_qsplitter.cpp

@@ -109,6 +109,8 @@ void tst_QSplitter::getSetCheck()
     QSplitter obj1;
     // bool QSplitter::opaqueResize()
     // void QSplitter::setOpaqueResize(bool)
+    bool styleHint = obj1.style()->styleHint(QStyle::SH_Splitter_OpaqueResize);
+    QCOMPARE(styleHint, obj1.opaqueResize());
     obj1.setOpaqueResize(false);
     QCOMPARE(false, obj1.opaqueResize());
     obj1.setOpaqueResize(true);