QskItemAnchors.h

/******************************************************************************
 * QSkinny - Copyright (C) The authors
 *           SPDX-License-Identifier: BSD-3-Clause
 *****************************************************************************/
 
#ifndef QSK_ITEM_ANCHORS_H
#define QSK_ITEM_ANCHORS_H
 
#include "QskGlobal.h"
#include <qnamespace.h>
#include <qpointer.h>
 
class QMarginsF;
class QQuickItem;
 
/*
    QskItemAnchors is a C++ API to access the Qt/Quick anchoring.
 
    Qt/Quick anchoring is a simple concept, that allows to attach
    borders ( Qt::AnchorPoint ) of one item ( attachedItem ) to borders of
    other items ( settledItem ).
 
    In opposite to anchoring layouts ( f.e QGraphicsAnchorLayout, QskAnchorLayout )
    the positions of the anchors are provided - not calculated. That makes
    Qt/Quick anchoring unsuitable for scenarios, where the space of
    a bounding rectangle has to be distributed.
 
    The implementation supports attaching to the parent or the siblings
    of attachedItem only ( conceptually this limitation would not be necessary ).
 
    Note that what is known in QML as "fill" or "centerIn" can be done
    using setBorderAnchors or setCenterAnchors. However the basic layout
    functionality provided from QskControl::autoLayoutChildren usually
    offers a more efficient implementation for most situations.
 
    Limitations:
        - access to baseline settings are not implemented
          ( for no other reason than Qt::AnchorPoint does not have it )
 */
class QSK_EXPORT QskItemAnchors
{
  public:
    QskItemAnchors( QQuickItem* attachedItem = nullptr );
    ~QskItemAnchors();
 
    QQuickItem* attachedItem() const;
 
    QQuickItem* settledItem( Qt::AnchorPoint ) const;
    Qt::AnchorPoint settledItemAnchorPoint( Qt::AnchorPoint ) const;
 
    bool operator==( const QskItemAnchors& ) const noexcept;
    bool operator!=( const QskItemAnchors& ) const noexcept;
 
    QMarginsF margins() const;
    void setMargins( const QMarginsF& );
 
    void setCenterOffsets( qreal horizontalOffset, qreal verticalOffset );
    void setCenterOffset( Qt::Orientation, qreal offset );
    qreal centerOffset( Qt::Orientation );
 
    // add to - or remove from - the list of anchors
    void addAnchor( Qt::AnchorPoint, QQuickItem*, Qt::AnchorPoint );
    void addAnchors( Qt::Corner, QQuickItem*, Qt::Corner );
    void removeAnchor( Qt::AnchorPoint );
 
    void clearAnchors();
 
    // replacing the list of anchors
    void setBorderAnchors( QQuickItem*, Qt::Orientations = Qt::Horizontal | Qt::Vertical );
    void setCenterAnchors( QQuickItem*, Qt::Orientations = Qt::Horizontal | Qt::Vertical );
 
  private:
    QPointer< QQuickItem > m_attachedItem;
};
 
inline bool QskItemAnchors::operator!=(
    const QskItemAnchors& other ) const noexcept
{
    return !( *this == other );
}
 
#endif