QwtPanner provides panning of a widget. More...

#include <qwt_panner.h>

Inheritance diagram for QwtPanner:

Collaboration diagram for QwtPanner:

Classes
class	PrivateData
Signals
void	panned (int dx, int dy)
void	moved (int dx, int dy)
Public Member Functions
	QwtPanner (QWidget *parent)
virtual	~QwtPanner ()
	Destructor.
void	setEnabled (bool)
	En/disable the panner.
bool	isEnabled () const
void	setMouseButton (int button, int buttonState=Qt::NoButton)
void	getMouseButton (int &button, int &buttonState) const
	Get the mouse button.
void	setAbortKey (int key, int state=Qt::NoButton)
void	getAbortKey (int &key, int &state) const
	Get the abort key.
void	setCursor (const QCursor &)
const QCursor	cursor () const
void	enableOrientation (Qt::Orientation, bool enable)
bool	isOrientationEnabled (Qt::Orientation) const
virtual bool	eventFilter (QObject , QEvent )
	Event filter.
Protected Member Functions
virtual void	widgetMousePressEvent (QMouseEvent *)
virtual void	widgetMouseReleaseEvent (QMouseEvent *)
virtual void	widgetMouseMoveEvent (QMouseEvent *)
virtual void	widgetKeyPressEvent (QKeyEvent *)
virtual void	widgetKeyReleaseEvent (QKeyEvent *)
virtual void	paintEvent (QPaintEvent *)
	Paint event.

Detailed Description

QwtPanner provides panning of a widget.

QwtPanner grabs the contents of a widget, that can be dragged in all directions. The offset between the start and the end position is emitted by the panned signal.

QwtPanner grabs the content of the widget into a pixmap and moves the pixmap around, without initiating any repaint events for the widget. Areas, that are not part of content are not painted while panning in in process. This makes panning fast enough for widgets, where repaints are too slow for mouse movements.

For widgets, where repaints are very fast it might be better to implement panning manually by mapping mouse events into paint events.

Definition at line 35 of file qwt_panner.h.

Constructor & Destructor Documentation

QwtPanner::QwtPanner ( QWidget * parent )

Creates an panner that is enabled for the left mouse button.

Parameters:

parent Parent widget to be panned

Definition at line 121 of file qwt_panner.cpp.

References setEnabled().

                                   :
    QWidget(parent)
{
    d_data = new PrivateData();

#if QT_VERSION >= 0x040000
    setAttribute(Qt::WA_TransparentForMouseEvents);
    setAttribute(Qt::WA_NoSystemBackground);
    setFocusPolicy(Qt::NoFocus);
#else
    setBackgroundMode(Qt::NoBackground);
    setFocusPolicy(QWidget::NoFocus);
#endif
    hide();

    setEnabled(true);
}

QwtPanner::~QwtPanner ( ) [virtual]

Destructor.

Definition at line 140 of file qwt_panner.cpp.

{
    delete d_data;
}

Member Function Documentation

const QCursor QwtPanner::cursor ( ) const

Returns:: Cursor that is active while panning

See also:: setCursor()

Definition at line 202 of file qwt_panner.cpp.

References QwtPanner::PrivateData::cursor.

{
    if ( d_data->cursor )
        return *d_data->cursor;

    if ( parentWidget() )
        return parentWidget()->cursor();

    return QCursor();
}

void QwtPanner::enableOrientation	(	Qt::Orientation	o,
		bool	enable
	)

Definition at line 264 of file qwt_panner.cpp.

References QwtPanner::PrivateData::orientations.

{
    if ( o == Qt::Vertical || o == Qt::Horizontal )
        d_data->orientations[o] = enable;
}

bool QwtPanner::eventFilter	(	QObject *	o,
		QEvent *	e
	)		`[virtual]`

Event filter.

When isEnabled() the mouse events of the observed widget are filtered.

See also:: widgetMousePressEvent(), widgetMouseReleaseEvent(), widgetMouseMoveEvent()

Definition at line 344 of file qwt_panner.cpp.

References widgetKeyPressEvent(), widgetKeyReleaseEvent(), widgetMouseMoveEvent(), widgetMousePressEvent(), and widgetMouseReleaseEvent().

{
    if ( o == NULL || o != parentWidget() )
        return false;

    switch(e->type())
    {
        case QEvent::MouseButtonPress:
        {
            widgetMousePressEvent((QMouseEvent *)e);
            break;
        }
        case QEvent::MouseMove:
        {
            widgetMouseMoveEvent((QMouseEvent *)e);
            break;
        }
        case QEvent::MouseButtonRelease:
        {
            widgetMouseReleaseEvent((QMouseEvent *)e);
            break;
        }
        case QEvent::KeyPress:
        {
            widgetKeyPressEvent((QKeyEvent *)e);
            break;
        }
        case QEvent::KeyRelease:
        {
            widgetKeyReleaseEvent((QKeyEvent *)e);
            break;
        }
        case QEvent::Paint:
        {
            if ( isVisible() )
                return true;
            break;
        }
        default:;
    }

    return false;
}

void QwtPanner::getAbortKey	(	int &	key,
		int &	state
	)		const

Get the abort key.

Definition at line 176 of file qwt_panner.cpp.

References QwtPanner::PrivateData::abortKey, and QwtPanner::PrivateData::abortKeyState.

{
    key = d_data->abortKey;
    state = d_data->abortKeyState;
}

void QwtPanner::getMouseButton	(	int &	button,
		int &	buttonState
	)		const

Get the mouse button.

Definition at line 156 of file qwt_panner.cpp.

References QwtPanner::PrivateData::button, and QwtPanner::PrivateData::buttonState.

{
    button = d_data->button;
    buttonState = d_data->buttonState;
}

bool QwtPanner::isEnabled ( ) const

Returns:: true when enabled, false otherwise

See also:: setEnabled, eventFilter()

Definition at line 290 of file qwt_panner.cpp.

References QwtPanner::PrivateData::isEnabled.

{
    return d_data->isEnabled;
}

bool QwtPanner::isOrientationEnabled ( Qt::Orientation o ) const

Return true if a orientatio is enabled

See also:: orientations(), setOrientations()

Definition at line 275 of file qwt_panner.cpp.

References QwtPanner::PrivateData::orientations.

Referenced by widgetMouseMoveEvent(), and widgetMouseReleaseEvent().

{
#if QT_VERSION >= 0x040000
    return d_data->orientations & o;
#else
    if ( o == Qt::Vertical || o == Qt::Horizontal )
        return d_data->orientations[o];
    return false;
#endif
}

void QwtPanner::moved	(	int	dx,
		int	dy
	)		`[signal]`

Signal emitted, while the widget moved, but panning is not finished.

Parameters:

dx	Offset in horizontal direction
dy	Offset in vertical direction

Referenced by widgetMouseMoveEvent().

void QwtPanner::paintEvent ( QPaintEvent * pe ) [protected, virtual]

Paint event.

Repaint the grabbed pixmap on its current position and fill the empty spaces by the background of the parent widget.

Parameters:

pe	Paint event

Definition at line 303 of file qwt_panner.cpp.

References QwtPanner::PrivateData::initialPos, QwtPanner::PrivateData::pixmap, and QwtPanner::PrivateData::pos.

{
    QPixmap pm(size());

    QPainter painter(&pm);

    const QColor bg =
#if QT_VERSION < 0x040000
        parentWidget()->palette().color(
            QPalette::Normal, QColorGroup::Background);
#else
        parentWidget()->palette().color(
            QPalette::Normal, QPalette::Background);
#endif

    painter.setPen(Qt::NoPen);
    painter.setBrush(QBrush(bg));
    painter.drawRect(0, 0, pm.width(), pm.height());

    int dx = d_data->pos.x() - d_data->initialPos.x();
    int dy = d_data->pos.y() - d_data->initialPos.y();

    QRect r(0, 0, d_data->pixmap.width(), d_data->pixmap.height());
    r.moveCenter(QPoint(r.center().x() + dx, r.center().y() + dy));

    painter.drawPixmap(r, d_data->pixmap);
    painter.end();

    painter.begin(this);
    painter.setClipRegion(pe->region());
    painter.drawPixmap(0, 0, pm);
}

void QwtPanner::panned	(	int	dx,
		int	dy
	)		`[signal]`

Signal emitted, when panning is done

Parameters:

dx	Offset in horizontal direction
dy	Offset in vertical direction

Referenced by QwtPlotPanner::QwtPlotPanner(), and widgetMouseReleaseEvent().

void QwtPanner::setAbortKey	(	int	key,
		int	state = `Qt::NoButton`
	)

Change the abort key The defaults are Qt::Key_Escape and Qt::NoButton

Parameters:

key	Key ( See Qt::Keycode )
state	State

Definition at line 169 of file qwt_panner.cpp.

References QwtPanner::PrivateData::abortKey, and QwtPanner::PrivateData::abortKeyState.

{
    d_data->abortKey = key;
    d_data->abortKeyState = state;
}

void QwtPanner::setCursor ( const QCursor & cursor )

Change the cursor, that is active while panning The default is the cursor of the parent widget.

Parameters:

cursor New cursor

See also:: setCursor()

Definition at line 191 of file qwt_panner.cpp.

References QwtPanner::PrivateData::cursor.

{
    d_data->cursor = new QCursor(cursor);
}

void QwtPanner::setEnabled ( bool on )

En/disable the panner.

When enabled is true an event filter is installed for the observed widget, otherwise the event filter is removed.

Parameters:

on	true or false

See also:: isEnabled(), eventFilter()

Definition at line 223 of file qwt_panner.cpp.

References QwtPanner::PrivateData::isEnabled.

Referenced by QwtPanner(), and widgetMousePressEvent().

{
    if ( d_data->isEnabled != on )
    {
        d_data->isEnabled = on;

        QWidget *w = parentWidget();
        if ( w )
        {
            if ( d_data->isEnabled )
            {
                w->installEventFilter(this);
            }
            else
            {
                w->removeEventFilter(this);
                hide();
            }
        }
    }
}

void QwtPanner::setMouseButton	(	int	button,
		int	buttonState = `Qt::NoButton`
	)

Change the mouse button The defaults are Qt::LeftButton and Qt::NoButton

Definition at line 149 of file qwt_panner.cpp.

References QwtPanner::PrivateData::button, and QwtPanner::PrivateData::buttonState.

{
    d_data->button = button;
    d_data->buttonState = buttonState;
}

void QwtPanner::widgetKeyPressEvent ( QKeyEvent * ke ) [protected, virtual]

Handle a key press event for the observed widget.

Parameters:

ke Key event

See also:: eventFilter(), widgetKeyReleaseEvent()

Definition at line 509 of file qwt_panner.cpp.

References QwtPanner::PrivateData::abortKey, QwtPanner::PrivateData::abortKeyState, and QwtPanner::PrivateData::pixmap.

Referenced by eventFilter().

{
    if ( ke->key() == d_data->abortKey )
    {
        const bool matched =
#if QT_VERSION < 0x040000
            (ke->state() & Qt::KeyButtonMask) ==
                (d_data->abortKeyState & Qt::KeyButtonMask);
#else
            (ke->modifiers() & Qt::KeyboardModifierMask) ==
                (int)(d_data->abortKeyState & Qt::KeyboardModifierMask);
#endif
        if ( matched )
        {
            hide();
#ifndef QT_NO_CURSOR
            showCursor(false);
#endif
            d_data->pixmap = QPixmap();
        }
    }
}

void QwtPanner::widgetKeyReleaseEvent ( QKeyEvent * ) [protected, virtual]

Handle a key release event for the observed widget.

See also:: eventFilter(), widgetKeyReleaseEvent()

Definition at line 536 of file qwt_panner.cpp.

Referenced by eventFilter().

{
}

void QwtPanner::widgetMouseMoveEvent ( QMouseEvent * me ) [protected, virtual]

Handle a mouse move event for the observed widget.

Parameters:

me	Mouse event

See also:: eventFilter(), widgetMousePressEvent(), widgetMouseReleaseEvent()

Definition at line 449 of file qwt_panner.cpp.

References QwtPanner::PrivateData::initialPos, isOrientationEnabled(), moved(), and QwtPanner::PrivateData::pos.

Referenced by eventFilter().

{
    if ( !isVisible() )
        return;

    QPoint pos = me->pos();
    if ( !isOrientationEnabled(Qt::Horizontal) )
        pos.setX(d_data->initialPos.x());
    if ( !isOrientationEnabled(Qt::Vertical) )
        pos.setY(d_data->initialPos.y());

    if ( pos != d_data->pos && rect().contains(pos) )
    {
        d_data->pos = pos;
        update();

        emit moved(d_data->pos.x() - d_data->initialPos.x(), 
            d_data->pos.y() - d_data->initialPos.y());
    }
}

void QwtPanner::widgetMousePressEvent ( QMouseEvent * me ) [protected, virtual]

Handle a mouse press event for the observed widget.

Parameters:

me	Mouse event

See also:: eventFilter(), widgetMouseReleaseEvent(), widgetMouseMoveEvent(),

Definition at line 395 of file qwt_panner.cpp.

References activePickers(), QwtPanner::PrivateData::button, QwtPanner::PrivateData::buttonState, QwtPanner::PrivateData::initialPos, int(), QwtPanner::PrivateData::pixmap, QwtPanner::PrivateData::pos, and setEnabled().

Referenced by eventFilter().

{
    if ( me->button() != d_data->button )
        return;

    QWidget *w = parentWidget();
    if ( w == NULL )
        return;

#if QT_VERSION < 0x040000
    if ( (me->state() & Qt::KeyButtonMask) !=
        (d_data->buttonState & Qt::KeyButtonMask) )
#else
    if ( (me->modifiers() & Qt::KeyboardModifierMask) !=
        (int)(d_data->buttonState & Qt::KeyboardModifierMask) )
#endif
    {
        return;
    }

#ifndef QT_NO_CURSOR
    showCursor(true);
#endif

    d_data->initialPos = d_data->pos = me->pos();

    QRect cr = parentWidget()->rect();
    if ( parentWidget()->inherits("QFrame") )
    {
        const QFrame* frame = (QFrame*)parentWidget();
        cr = frame->contentsRect();
    }
    setGeometry(cr);

    // We don't want to grab the picker !
    QwtArray<QwtPicker *> pickers = activePickers(parentWidget());
    for ( int i = 0; i < (int)pickers.size(); i++ )
        pickers[i]->setEnabled(false);

    d_data->pixmap = QPixmap::grabWidget(parentWidget(),
        cr.x(), cr.y(), cr.width(), cr.height());

    for ( int i = 0; i < (int)pickers.size(); i++ )
        pickers[i]->setEnabled(true);

    show();
}

void QwtPanner::widgetMouseReleaseEvent ( QMouseEvent * me ) [protected, virtual]

Handle a mouse release event for the observed widget.

Parameters:

me	Mouse event

See also:: eventFilter(), widgetMousePressEvent(), widgetMouseMoveEvent(),

Definition at line 477 of file qwt_panner.cpp.

References QwtPanner::PrivateData::initialPos, isOrientationEnabled(), panned(), QwtPanner::PrivateData::pixmap, and QwtPanner::PrivateData::pos.

Referenced by eventFilter().

{
    if ( isVisible() )
    {
        hide();
#ifndef QT_NO_CURSOR
        showCursor(false);
#endif

        QPoint pos = me->pos();
        if ( !isOrientationEnabled(Qt::Horizontal) )
            pos.setX(d_data->initialPos.x());
        if ( !isOrientationEnabled(Qt::Vertical) )
            pos.setY(d_data->initialPos.y());

        d_data->pixmap = QPixmap();
        d_data->pos = pos;

        if ( d_data->pos != d_data->initialPos )
        {
            emit panned(d_data->pos.x() - d_data->initialPos.x(), 
                d_data->pos.y() - d_data->initialPos.y());
        }
    }
}

The documentation for this class was generated from the following files:

QwtPanner Class Reference

Classes

Signals

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation