Add support for RTL

Introduce the property layoutDirection. This matches the API of
Grid, Row, and Column.

Change-Id: I7282e3bc8ac1e1643f278b9069a319b2e5b1c323
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>

2 files changed, 90 insertions, 4 deletions

diff --git a/src/layouts/qquicklinearlayout.cpp b/src/layouts/qquicklinearlayout.cpp
index 931bfed5..c8015608 100644
--- a/src/layouts/qquicklinearlayout.cpp
+++ b/src/layouts/qquicklinearlayout.cpp
@@ -216,6 +216,42 @@ QSizeF QQuickGridLayoutBase::sizeHint(Qt::SizeHint whichSizeHint) const
     return d->engine.sizeHint(whichSizeHint, QSizeF());
 }
 
+/*!
+    \qmlproperty enumeration GridLayout::layoutDirection
+
+    This property holds the layout direction of the grid layout - it controls whether items are
+    laid out from left ro right or right to left. If \c Qt.RightToLeft is specified,
+    left-aligned items will be right-aligned and right-aligned items will be left-aligned.
+
+    Possible values:
+
+    \list
+    \li Qt.LeftToRight (default) - Items are laid out from left to right.
+    \li Qt.RightToLeft - Items are laid out from right to left
+    \endlist
+
+    \sa RowLayout::layoutDirection, ColumnLayout::layoutDirection
+*/
+Qt::LayoutDirection QQuickGridLayoutBase::layoutDirection() const
+{
+    Q_D(const QQuickGridLayoutBase);
+    return d->m_layoutDirection;
+}
+
+void QQuickGridLayoutBase::setLayoutDirection(Qt::LayoutDirection dir)
+{
+    Q_D(QQuickGridLayoutBase);
+    d->m_layoutDirection = dir;
+    invalidate();
+}
+
+Qt::LayoutDirection QQuickGridLayoutBase::effectiveLayoutDirection() const
+{
+    Q_D(const QQuickGridLayoutBase);
+    return !d->effectiveLayoutMirror == (layoutDirection() == Qt::LeftToRight)
+                                      ? Qt::LeftToRight : Qt::RightToLeft;
+}
+
 QQuickGridLayoutBase::~QQuickGridLayoutBase()
 {
     d_func()->m_isReady = false;
@@ -420,7 +456,7 @@ void QQuickGridLayoutBase::rearrange(const QSizeF &size)
         return;
 
     quickLayoutDebug() << objectName() << "QQuickGridLayoutBase::rearrange()" << size;
-    Qt::LayoutDirection visualDir = Qt::LeftToRight;    // ### Fix if RTL support is needed
+    Qt::LayoutDirection visualDir = effectiveLayoutDirection();
     d->engine.setVisualDirection(visualDir);
 
     /*
@@ -732,6 +768,40 @@ QQuickLinearLayout::QQuickLinearLayout(Qt::Orientation orientation,
 }
 
 /*!
+    \qmlproperty enumeration RowLayout::layoutDirection
+
+    This property holds the layout direction of the row layout - it controls whether items are laid
+    out from left ro right or right to left. If \c Qt.RightToLeft is specified,
+    left-aligned items will be right-aligned and right-aligned items will be left-aligned.
+
+    Possible values:
+
+    \list
+    \li Qt.LeftToRight (default) - Items are laid out from left to right.
+    \li Qt.RightToLeft - Items are laid out from right to left
+    \endlist
+
+    \sa GridLayout::layoutDirection, ColumnLayout::layoutDirection
+*/
+/*!
+    \qmlproperty enumeration ColumnLayout::layoutDirection
+
+    This property holds the layout direction of the column layout - it controls whether items are laid
+    out from left ro right or right to left. If \c Qt.RightToLeft is specified,
+    left-aligned items will be right-aligned and right-aligned items will be left-aligned.
+
+    Possible values:
+
+    \list
+    \li Qt.LeftToRight (default) - Items are laid out from left to right.
+    \li Qt.RightToLeft - Items are laid out from right to left
+    \endlist
+
+    \sa GridLayout::layoutDirection, RowLayout::layoutDirection
+*/
+
+
+/*!
     \qmlproperty real RowLayout::spacing
 
     This property holds the spacing between each cell.
diff --git a/src/layouts/qquicklinearlayout_p.h b/src/layouts/qquicklinearlayout_p.h
index b38bd97f..827767b3 100644
--- a/src/layouts/qquicklinearlayout_p.h
+++ b/src/layouts/qquicklinearlayout_p.h
@@ -58,16 +58,23 @@ class QQuickGridLayoutBasePrivate;
 class QQuickGridLayoutBase : public QQuickLayout
 {
     Q_OBJECT
+
+    Q_PROPERTY(Qt::LayoutDirection layoutDirection READ layoutDirection WRITE setLayoutDirection NOTIFY layoutDirectionChanged)
+
 public:
     explicit QQuickGridLayoutBase(QQuickGridLayoutBasePrivate &dd,
                                   Qt::Orientation orientation,
                                   QQuickItem *parent = 0);
+
     ~QQuickGridLayoutBase();
     void componentComplete();
     void invalidate(QQuickItem *childItem = 0);
     Qt::Orientation orientation() const;
     void setOrientation(Qt::Orientation orientation);
     QSizeF sizeHint(Qt::SizeHint whichSizeHint) const Q_DECL_OVERRIDE;
+    Qt::LayoutDirection layoutDirection() const;
+    void setLayoutDirection(Qt::LayoutDirection dir);
+    Qt::LayoutDirection effectiveLayoutDirection() const;
 
 protected:
     void updateLayoutItems();
@@ -78,6 +85,9 @@ protected:
     void geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry);
     bool shouldIgnoreItem(QQuickItem *child, QQuickLayoutAttached *&info, QSizeF *sizeHints);
 
+signals:
+    void layoutDirectionChanged();
+
 protected slots:
     void onItemVisibleChanged();
     void onItemDestroyed();
@@ -95,11 +105,16 @@ class QQuickGridLayoutBasePrivate : public QQuickLayoutPrivate
     Q_DECLARE_PUBLIC(QQuickGridLayoutBase)
 
 public:
-    QQuickGridLayoutBasePrivate() : m_disableRearrange(true), m_isReady(false) { }
+    QQuickGridLayoutBasePrivate() : m_disableRearrange(true)
+                                    , m_isReady(false)
+                                    , m_layoutDirection(Qt::LeftToRight)
+                                    {}
     QQuickGridLayoutEngine engine;
     Qt::Orientation orientation;
-    bool m_disableRearrange;
-    bool m_isReady;
+    unsigned m_disableRearrange : 1;
+    unsigned m_isReady : 1;
+    Qt::LayoutDirection m_layoutDirection : 2;
+
     QSet<QQuickItem *> m_ignoredItems;
 };
 
@@ -112,6 +127,7 @@ class QQuickGridLayoutPrivate;
 class QQuickGridLayout : public QQuickGridLayoutBase
 {
     Q_OBJECT
+
     Q_PROPERTY(qreal columnSpacing READ columnSpacing WRITE setColumnSpacing NOTIFY columnSpacingChanged)
     Q_PROPERTY(qreal rowSpacing READ rowSpacing WRITE setRowSpacing NOTIFY rowSpacingChanged)
     Q_PROPERTY(int columns READ columns WRITE setColumns NOTIFY columnsChanged)