katie/src/gui/widgets/qrubberband.cpp

/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Copyright (C) 2016-2020 Ivailo Monev
**
** This file is part of the QtGui module of the Katie Toolkit.
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#include "qbitmap.h"
#include "qevent.h"
#include "qstylepainter.h"
#include "qrubberband.h"
#include "qtimer.h"

#ifndef QT_NO_RUBBERBAND

#include "qstyle.h"
#include "qstyleoption.h"
#include "qdebug.h"
#include "qwidget_p.h"

QT_BEGIN_NAMESPACE

//### a rubberband window type would be a more elegant solution
#define RUBBERBAND_WINDOW_TYPE Qt::ToolTip

class QRubberBandPrivate : public QWidgetPrivate
{
    Q_DECLARE_PUBLIC(QRubberBand)
public:
    QRect rect;
    QRubberBand::Shape shape;
    QRegion clipping;
    void updateMask();
};

/*!
    Initialize \a option with the values from this QRubberBand. This method
    is useful for subclasses when they need a QStyleOptionRubberBand, but don't want
    to fill in all the information themselves.

    \sa QStyleOption::initFrom()
*/
void QRubberBand::initStyleOption(QStyleOptionRubberBand *option) const
{
    if (!option)
        return;
    option->initFrom(this);
    option->shape = d_func()->shape;
    option->opaque = true;
}

/*!
    \class QRubberBand
    \brief The QRubberBand class provides a rectangle or line that can
    indicate a selection or a boundary.

    A rubber band is often used to show a new bounding area (as in a
    QSplitter or a QDockWidget that is undocking). Historically this has
    been implemented using a QPainter and XOR, but this approach
    doesn't always work properly since rendering can happen in the
    window below the rubber band, but before the rubber band has been
    "erased".

    You can create a QRubberBand whenever you need to render a rubber band
    around a given area (or to represent a single line), then call
    setGeometry(), move() or resize() to position and size it. A common
    pattern is to do this in conjunction with mouse events. For example:

    \snippet doc/src/snippets/code/src_gui_widgets_qrubberband.cpp 0

    If you pass a parent to QRubberBand's constructor, the rubber band will
    display only inside its parent, but stays on top of other child widgets.
    If no parent is passed, QRubberBand will act as a top-level widget.

    Call show() to make the rubber band visible; also when the
    rubber band is not a top-level. Hiding or destroying
    the widget will make the rubber band disappear. The rubber band
    can be a \l Rectangle or a \l Line (vertical or horizontal),
    depending on the shape() it was given when constructed.
*/

// ### DOC: How about some nice convenience constructors?
//QRubberBand::QRubberBand(QRubberBand::Type t, const QRect &rect, QWidget *p)
//QRubberBand::QRubberBand(QRubberBand::Type t, int x, int y, int w, int h, QWidget *p)

/*!
    Constructs a rubber band of shape \a s, with parent \a p.

    By default a rectangular rubber band (\a s is \c Rectangle) will
    use a mask, so that a small border of the rectangle is all
    that is visible. Some styles (e.g., native Mac OS X) will
    change this and call QWidget::setWindowOpacity() to make a
    semi-transparent filled selection rectangle.
*/
QRubberBand::QRubberBand(Shape s, QWidget *p)
    : QWidget(*new QRubberBandPrivate, p, (p && p->windowType() != Qt::Desktop) ? Qt::Widget : RUBBERBAND_WINDOW_TYPE)
{
    Q_D(QRubberBand);
    d->shape = s;
    setAttribute(Qt::WA_TransparentForMouseEvents);
    setAttribute(Qt::WA_NoSystemBackground);
    setAttribute(Qt::WA_WState_ExplicitShowHide);
    setVisible(false);
}

/*!
    Destructor.
*/
QRubberBand::~QRubberBand()
{
}

/*!
    \enum QRubberBand::Shape

    This enum specifies what shape a QRubberBand should have. This is
    a drawing hint that is passed down to the style system, and can be
    interpreted by each QStyle.

    \value Line A QRubberBand can represent a vertical or horizontal
                line. Geometry is still given in rect() and the line
                will fill the given geometry on most styles.

    \value Rectangle A QRubberBand can represent a rectangle. Some
                     styles will interpret this as a filled (often
                     semi-transparent) rectangle, or a rectangular
                     outline.
*/

/*!
  Returns the shape of this rubber band. The shape can only be set
  upon construction.
*/
QRubberBand::Shape QRubberBand::shape() const
{
    Q_D(const QRubberBand);
    return d->shape;
}

/*!
    \internal
*/
void QRubberBandPrivate::updateMask()
{
    Q_Q(QRubberBand);
    QStyleHintReturnMask mask;
    QStyleOptionRubberBand opt;
    q->initStyleOption(&opt);
    if (q->style()->styleHint(QStyle::SH_RubberBand_Mask, &opt, q, &mask)) {
        q->setMask(mask.region);
    } else {
        q->clearMask();
    }
}

/*!
    \reimp
*/
void QRubberBand::paintEvent(QPaintEvent *)
{
    QStylePainter painter(this);
    QStyleOptionRubberBand option;
    initStyleOption(&option);
    painter.drawControl(QStyle::CE_RubberBand, option);
}

/*!
    \reimp
*/
void QRubberBand::changeEvent(QEvent *e)
{
    QWidget::changeEvent(e);
    switch (e->type()) {
    case QEvent::ParentChange:
        if (parent()) {
            setWindowFlags(windowFlags() & ~RUBBERBAND_WINDOW_TYPE);
        } else {
            setWindowFlags(windowFlags() | RUBBERBAND_WINDOW_TYPE);
        }
        break;
    default:
        break;
    }

    if (e->type() == QEvent::ZOrderChange)
        raise();
}

/*!
    \reimp
*/
void QRubberBand::showEvent(QShowEvent *e)
{
    raise();
    e->ignore();
}

/*!
    \reimp
*/
void QRubberBand::resizeEvent(QResizeEvent *)
{
    Q_D(QRubberBand);
    d->updateMask();
}

/*!
    \reimp
*/
void QRubberBand::moveEvent(QMoveEvent *)
{
    Q_D(QRubberBand);
    d->updateMask();
}

/*!
    \fn void QRubberBand::move(const QPoint &p);

    \overload

    Moves the rubberband to point \a p.

    \sa resize()
*/

/*!
    \fn void QRubberBand::move(int x, int y);

    Moves the rubberband to point (\a x, \a y).

    \sa resize()
*/

/*!
    \fn void QRubberBand::resize(const QSize &size);

    \overload

    Resizes the rubberband so that its new size is \a size.

    \sa move()
*/

/*!
    \fn void QRubberBand::resize(int width, int height);

    Resizes the rubberband so that its width is \a width, and its
    height is \a height.

    \sa move()
*/

QT_END_NAMESPACE

#include "moc_qrubberband.h"

#endif // QT_NO_RUBBERBAND