Add SplitView

SplitView is an important tool for desktop applications that do not
want to use a dock widget-style approach for their user interface.
It allows users to have some degree of control over the sizing of
elements in the UI, as well as the ability to conveniently serialize
those sizes so that they're remembered across sessions.

The main differences between this and the SplitView in
Qt Quick Controls 1 are:

- Has its own SplitView attached properties, rather than relying on
  the Layout attached properties (which required an additional import).
- Uses the attached preferredWidth and preferredHeight properties
  as well as Item's implicitWidth/implicitHeight properties
  for the preferred size of items, rather than using the width and
  height properties.
- Inherits from Container, so supports most of its API (though some
  parts of the API, like the currentIndex-related stuff, make no
  sense for SplitView).
- Uses attached SplitHandle properties for the handle delegate to
  visualize hovered/pressed effects.
- Offers convenience API for serializing the user's preferred sizes.

[ChangeLog][Controls][SplitView] Introduced SplitView, a control that
lays out items horizontally or vertically with a draggable splitter
between each item.

Task-number: QTBUG-56318
Change-Id: I3da91643ab312eb9ef5b0567da4e758f17747192
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

1 files changed, 173 insertions, 0 deletions

diff --git a/src/quicktemplates2/qquicksplitview_p_p.h b/src/quicktemplates2/qquicksplitview_p_p.h
new file mode 100644
index 00000000..65fbd900
--- /dev/null
+++ b/src/quicktemplates2/qquicksplitview_p_p.h
@@ -0,0 +1,173 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Quick Templates 2 module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** 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 The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/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 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later 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 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QQUICKSPLITVIEW_P_P_H
+#define QQUICKSPLITVIEW_P_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 <QtQuickTemplates2/private/qquickcontainer_p_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QQuickSplitView;
+class QQuickSplitViewAttached;
+class QQuickSplitHandleAttached;
+
+class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickSplitViewPrivate : public QQuickContainerPrivate
+{
+    Q_DECLARE_PUBLIC(QQuickSplitView)
+
+public:
+    void updateFillIndex();
+    void layoutResizeSplitItems(qreal &usedWidth, qreal &usedHeight, int &indexBeingResizedDueToDrag);
+    void layoutResizeFillItem(QQuickItem *fillItem, qreal &usedWidth, qreal &usedHeight, int indexBeingResizedDueToDrag);
+    void layoutPositionItems(const QQuickItem *fillItem);
+    void layout();
+    void createHandles();
+    void createHandleItem(int index);
+    void removeExcessHandles();
+    void destroyHandles();
+    void resizeHandle(QQuickItem *handleItem);
+    void resizeHandles();
+    void updateHandleVisibilities();
+    void setResizing(bool resizing);
+
+    bool isHorizontal() const;
+    qreal accumulatedSize(int firstIndex, int lastIndex) const;
+
+    struct EffectiveSizeData {
+        qreal effectiveMinimumWidth;
+        qreal effectiveMinimumHeight;
+        qreal effectivePreferredWidth;
+        qreal effectivePreferredHeight;
+        qreal effectiveMaximumWidth;
+        qreal effectiveMaximumHeight;
+    };
+
+    EffectiveSizeData effectiveSizeData(const QQuickItemPrivate *itemPrivate,
+        const QQuickSplitViewAttached *attached) const;
+
+    int handleIndexForSplitIndex(int splitIndex) const;
+
+    QQuickItem *getContentItem() override;
+    void handlePress(const QPointF &point) override;
+    void handleMove(const QPointF &point) override;
+    void handleRelease(const QPointF &point) override;
+
+    void itemVisibilityChanged(QQuickItem *item) override;
+
+    static QQuickSplitViewPrivate *get(QQuickSplitView *splitView);
+
+private:
+    Qt::Orientation m_orientation = Qt::Horizontal;
+    QQmlComponent *m_handle = nullptr;
+    QVector<QQuickItem*> m_handleItems;
+    int m_hoveredHandleIndex = -1;
+    int m_pressedHandleIndex = -1;
+    QPointF m_pressPos;
+    QPointF m_mousePos;
+    QPointF m_handlePosBeforePress;
+    qreal m_leftOrTopItemSizeBeforePress = 0.0;
+    qreal m_rightOrBottomItemSizeBeforePress = 0.0;
+    int m_fillIndex = -1;
+    bool m_layingOut = false;
+    bool m_resizing = false;
+};
+
+class QQuickSplitViewAttachedPrivate : public QObjectPrivate
+{
+    Q_DECLARE_PUBLIC(QQuickSplitViewAttached)
+
+public:
+    QQuickSplitViewAttachedPrivate();
+
+    void setView(QQuickSplitView *newView);
+    void layoutView();
+
+    static QQuickSplitViewAttachedPrivate *get(QQuickSplitViewAttached *attached);
+    static const QQuickSplitViewAttachedPrivate *get(const QQuickSplitViewAttached *attached);
+
+    QQuickItem *m_splitItem = nullptr;
+    QQuickSplitView *m_splitView = nullptr;
+
+    unsigned m_fillWidth : 1;
+    unsigned m_fillHeight : 1;
+    unsigned m_isFillWidthSet : 1;
+    unsigned m_isFillHeightSet : 1;
+    unsigned m_isMinimumWidthSet : 1;
+    unsigned m_isMinimumHeightSet : 1;
+    unsigned m_isPreferredWidthSet : 1;
+    unsigned m_isPreferredHeightSet : 1;
+    unsigned m_isMaximumWidthSet : 1;
+    unsigned m_isMaximumHeightSet : 1;
+    qreal m_minimumWidth;
+    qreal m_minimumHeight;
+    qreal m_preferredWidth;
+    qreal m_preferredHeight;
+    qreal m_maximumWidth;
+    qreal m_maximumHeight;
+};
+
+class QQuickSplitHandleAttachedPrivate : public QObjectPrivate
+{
+    Q_DECLARE_PUBLIC(QQuickSplitHandleAttached)
+
+public:
+    QQuickSplitHandleAttachedPrivate();
+
+    void setHovered(bool hovered);
+    void setPressed(bool pressed);
+
+    static QQuickSplitHandleAttachedPrivate *get(QQuickSplitHandleAttached *attached);
+    static const QQuickSplitHandleAttachedPrivate *get(const QQuickSplitHandleAttached *attached);
+
+    unsigned m_hovered : 1;
+    unsigned m_pressed : 1;
+};
+
+QT_END_NAMESPACE
+
+#endif // QQUICKSPLITVIEW_P_P_H