Qwt User's Guide  6.1.1
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QwtPanner Class Reference

QwtPanner provides panning of a widget. More...

#include <qwt_panner.h>

Inheritance diagram for QwtPanner:
Inheritance graph
[legend]

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. More...
 
bool isEnabled () const
 
void setMouseButton (Qt::MouseButton, Qt::KeyboardModifiers=Qt::NoModifier)
 
void getMouseButton (Qt::MouseButton &button, Qt::KeyboardModifiers &) const
 Get mouse button and modifiers used for panning.
 
void setAbortKey (int key, Qt::KeyboardModifiers=Qt::NoModifier)
 
void getAbortKey (int &key, Qt::KeyboardModifiers &) const
 Get the abort key and modifiers.
 
void setCursor (const QCursor &)
 
const QCursor cursor () const
 
void setOrientations (Qt::Orientations)
 
Qt::Orientations orientations () const
 Return the orientation, where paning is enabled.
 
bool isOrientationEnabled (Qt::Orientation) const
 
virtual bool eventFilter (QObject *, QEvent *)
 Event filter. More...
 

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. More...
 
virtual QBitmap contentsMask () const
 Calculate a mask for the contents of the panned widget. More...
 
virtual QPixmap grab () const
 

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. 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.

Constructor & Destructor Documentation

QwtPanner::QwtPanner ( QWidget *  parent)

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

Parameters
parentParent widget to be panned

Member Function Documentation

QBitmap QwtPanner::contentsMask ( ) const
protectedvirtual

Calculate a mask for the contents of the panned widget.

Sometimes only parts of the contents of a widget should be panned. F.e. for a widget with a styled background with rounded borders only the area inside of the border should be panned.

Returns
An empty bitmap, indicating no mask

Reimplemented in QwtPlotPanner.

const QCursor QwtPanner::cursor ( ) const
Returns
Cursor that is active while panning
See Also
setCursor()
bool QwtPanner::eventFilter ( QObject *  object,
QEvent *  event 
)
virtual

Event filter.

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

Parameters
objectObject to be filtered
eventEvent
Returns
Always false, beside for paint events for the parent widget.
See Also
widgetMousePressEvent(), widgetMouseReleaseEvent(), widgetMouseMoveEvent()
QPixmap QwtPanner::grab ( ) const
protectedvirtual

Grab the widget into a pixmap.

Returns
Grabbed pixmap

Reimplemented in QwtPlotPanner.

bool QwtPanner::isEnabled ( ) const
Returns
true when enabled, false otherwise
See Also
setEnabled, eventFilter()
bool QwtPanner::isOrientationEnabled ( Qt::Orientation  o) const
Returns
True if an orientation is enabled
See Also
orientations(), setOrientations()
void QwtPanner::moved ( int  dx,
int  dy 
)
signal

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

Parameters
dxOffset in horizontal direction
dyOffset in vertical direction
void QwtPanner::paintEvent ( QPaintEvent *  pe)
protectedvirtual

Paint event.

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

Parameters
pePaint event
void QwtPanner::panned ( int  dx,
int  dy 
)
signal

Signal emitted, when panning is done

Parameters
dxOffset in horizontal direction
dyOffset in vertical direction
void QwtPanner::setAbortKey ( int  key,
Qt::KeyboardModifiers  modifiers = Qt::NoModifier 
)

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

Parameters
keyKey ( See Qt::Keycode )
modifiersKeyboard modifiers
void QwtPanner::setCursor ( const QCursor &  cursor)

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

Parameters
cursorNew cursor
See Also
setCursor()
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
ontrue or false
See Also
isEnabled(), eventFilter()
void QwtPanner::setMouseButton ( Qt::MouseButton  button,
Qt::KeyboardModifiers  modifiers = Qt::NoModifier 
)

Change the mouse button and modifiers used for panning The defaults are Qt::LeftButton and Qt::NoModifier

void QwtPanner::setOrientations ( Qt::Orientations  o)

Set the orientations, where panning is enabled The default value is in both directions: Qt::Horizontal | Qt::Vertical

/param o Orientation

void QwtPanner::widgetKeyPressEvent ( QKeyEvent *  keyEvent)
protectedvirtual

Handle a key press event for the observed widget.

Parameters
keyEventKey event
See Also
eventFilter(), widgetKeyReleaseEvent()
void QwtPanner::widgetKeyReleaseEvent ( QKeyEvent *  keyEvent)
protectedvirtual

Handle a key release event for the observed widget.

Parameters
keyEventKey event
See Also
eventFilter(), widgetKeyReleaseEvent()
void QwtPanner::widgetMouseMoveEvent ( QMouseEvent *  mouseEvent)
protectedvirtual

Handle a mouse move event for the observed widget.

Parameters
mouseEventMouse event
See Also
eventFilter(), widgetMousePressEvent(), widgetMouseReleaseEvent()
void QwtPanner::widgetMousePressEvent ( QMouseEvent *  mouseEvent)
protectedvirtual

Handle a mouse press event for the observed widget.

Parameters
mouseEventMouse event
See Also
eventFilter(), widgetMouseReleaseEvent(), widgetMouseMoveEvent(),
void QwtPanner::widgetMouseReleaseEvent ( QMouseEvent *  mouseEvent)
protectedvirtual

Handle a mouse release event for the observed widget.

Parameters
mouseEventMouse event
See Also
eventFilter(), widgetMousePressEvent(), widgetMouseMoveEvent(),