QwtPanner - Man Page

QwtPanner provides panning of a widget.

Synopsis

#include <qwt_panner.h>

Inherits QWidget.

Inherited by QwtPlotPanner.

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 (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.

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

parent Parent widget to be panned

Member Function Documentation

QBitmap QwtPanner::contentsMask () const [protected], [virtual]

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

object Object to be filtered
event Event

Returns

Always false, beside for paint events for the parent widget.

See also

widgetMousePressEvent(), widgetMouseReleaseEvent(), widgetMouseMoveEvent()

QPixmap QwtPanner::grab () const [protected], [virtual]

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

dx Offset in horizontal direction
dy Offset in vertical direction

void QwtPanner::paintEvent (QPaintEvent * event) [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

event Paint event

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

void QwtPanner::setAbortKey (int key, Qt::KeyboardModifiers modifiers = Qt::NoModifier)

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

Parameters

key Key ( See Qt::Keycode )
modifiers Keyboard 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

cursor New 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

on true 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) [protected], [virtual]

Handle a key press event for the observed widget.

Parameters

keyEvent Key event

See also

eventFilter(), widgetKeyReleaseEvent()

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

Handle a key release event for the observed widget.

Parameters

keyEvent Key event

See also

eventFilter(), widgetKeyReleaseEvent()

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

Handle a mouse move event for the observed widget.

Parameters

mouseEvent Mouse event

See also

eventFilter(), widgetMousePressEvent(), widgetMouseReleaseEvent()

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

Handle a mouse press event for the observed widget.

Parameters

mouseEvent Mouse event

See also

eventFilter(), widgetMouseReleaseEvent(), widgetMouseMoveEvent(),

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

Handle a mouse release event for the observed widget.

Parameters

mouseEvent Mouse event

See also

eventFilter(), widgetMousePressEvent(), widgetMouseMoveEvent(),

Author

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Info

Mon Jun 1 2020 Version 6.1.5 Qwt User's Guide