Qwt User's Guide 6.1.2

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QwtMagnifier Class Referenceabstract

QwtMagnifier provides zooming, by magnifying in steps. More...

`#include <qwt_magnifier.h>`

Inheritance diagram for QwtMagnifier:
[legend]

## Public Member Functions
| QwtMagnifier (QWidget *)
virtual | ~QwtMagnifier ()
| Destructor.
QWidget * | parentWidget ()
const QWidget * | parentWidget () const
void | setEnabled (bool)
| En/disable the magnifier. More...
bool | isEnabled () const
void | setMouseFactor (double)
| Change the mouse factor. More...
double | mouseFactor () const
void | setMouseButton (Qt::MouseButton, Qt::KeyboardModifiers=Qt::NoModifier)
void | getMouseButton (Qt::MouseButton &, Qt::KeyboardModifiers &) const
void | setWheelFactor (double)
| Change the wheel factor. More...
double | wheelFactor () const
void | setWheelModifiers (Qt::KeyboardModifiers)
Qt::KeyboardModifiers | wheelModifiers () const
void | setKeyFactor (double)
| Change the key factor. More...
double | keyFactor () const
void | setZoomInKey (int key, Qt::KeyboardModifiers=Qt::NoModifier)
void | getZoomInKey (int &key, Qt::KeyboardModifiers &) const
| Retrieve the settings of the zoom in key. More...
void | setZoomOutKey (int key, Qt::KeyboardModifiers=Qt::NoModifier)
void | getZoomOutKey (int &key, Qt::KeyboardModifiers &) const
| Retrieve the settings of the zoom out key. More...
virtual bool | eventFilter (QObject *, QEvent *)
| Event filter. More...

## Protected Member Functions
virtual void | rescale (double factor)=0
virtual void | widgetMousePressEvent (QMouseEvent *)
virtual void | widgetMouseReleaseEvent (QMouseEvent *)
virtual void | widgetMouseMoveEvent (QMouseEvent *)
virtual void | widgetWheelEvent (QWheelEvent *)
virtual void | widgetKeyPressEvent (QKeyEvent *)
virtual void | widgetKeyReleaseEvent (QKeyEvent *)

## Detailed Description

QwtMagnifier provides zooming, by magnifying in steps.

Using QwtMagnifier a plot can be zoomed in/out in steps using keys, the mouse wheel or moving a mouse button in vertical direction.

## Constructor & Destructor Documentation

QwtMagnifier::QwtMagnifier | ( | QWidget * | parent | ) |
| explicit

Constructor

Parameters

  parent | Widget to be magnified

## Member Function Documentation

bool QwtMagnifier::eventFilter | ( | QObject * | object,
|  | QEvent * | event
| ) |  |
| virtual

Event filter.

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

Parameters

  object | Object to be filtered
  event | Event

Returns
  Forwarded to QObject::eventFilter()

See Also
  widgetMousePressEvent(), widgetMouseReleaseEvent(), widgetMouseMoveEvent(), widgetWheelEvent(), widgetKeyPressEvent() widgetKeyReleaseEvent()

void QwtMagnifier::getMouseButton | ( | Qt::MouseButton & | button,
|  | Qt::KeyboardModifiers & | modifiers
| ) |  | const

See Also
  setMouseButton()

void QwtMagnifier::getZoomInKey | ( | int & | key,
|  | Qt::KeyboardModifiers & | modifiers
| ) |  | const

Retrieve the settings of the zoom in key.

Parameters

  key | Key code, see Qt::Key
  modifiers | Keyboard modifiers

See Also
  setZoomInKey()

void QwtMagnifier::getZoomOutKey | ( | int & | key,
|  | Qt::KeyboardModifiers & | modifiers
| ) |  | const

Retrieve the settings of the zoom out key.

Parameters

  key | Key code, see Qt::Key
  modifiers | Keyboard modifiers

See Also
  setZoomOutKey()

bool QwtMagnifier::isEnabled | ( |  | ) | const

Returns
  true when enabled, false otherwise

See Also
  setEnabled(), eventFilter()

double QwtMagnifier::keyFactor | ( |  | ) | const

Returns
  Key factor

See Also
  setKeyFactor()

double QwtMagnifier::mouseFactor | ( |  | ) | const

Returns
  Mouse factor

See Also
  setMouseFactor()

QWidget * QwtMagnifier::parentWidget | ( |  | ) |

Returns
  Parent widget, where the rescaling happens

const QWidget * QwtMagnifier::parentWidget | ( |  | ) | const

Returns
  Parent widget, where the rescaling happens

virtual void QwtMagnifier::rescale | ( | double | factor | ) |
| protected pure virtual

Rescale the parent widget

Parameters

  factor | Scale factor

Implemented in QwtPlotMagnifier.

void QwtMagnifier::setEnabled | ( | bool | on | ) |

En/disable the magnifier.

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 QwtMagnifier::setKeyFactor | ( | double | factor | ) |

Change the key factor.

The key factor defines the ratio between the current range on the parent widget and the zoomed range for each key press of the zoom in/out keys. The default value is 0.9.

Parameters

  factor | Key factor

See Also
  keyFactor(), setZoomInKey(), setZoomOutKey(), setWheelFactor, setMouseFactor()

void QwtMagnifier::setMouseButton | ( | Qt::MouseButton | button,
|  | Qt::KeyboardModifiers | modifiers = `Qt::NoModifier`
| ) |  |

Assign the mouse button, that is used for zooming in/out. The default value is Qt::RightButton.

Parameters

  button | Button
  modifiers | Keyboard modifiers

See Also
  getMouseButton()

void QwtMagnifier::setMouseFactor | ( | double | factor | ) |

Change the mouse factor.

The mouse factor defines the ratio between the current range on the parent widget and the zoomed range for each vertical mouse movement. The default value is 0.95.

Parameters

  factor | Wheel factor

See Also
  mouseFactor(), setMouseButton(), setWheelFactor(), setKeyFactor()

void QwtMagnifier::setWheelFactor | ( | double | factor | ) |

Change the wheel factor.

The wheel factor defines the ratio between the current range on the parent widget and the zoomed range for each step of the wheel.

Use values > 1 for magnification (i.e. 2.0) and values < 1 for scaling down (i.e. 1/2.0 = 0.5). You can use this feature for inverting the direction of the wheel.

The default value is 0.9.

Parameters

  factor | Wheel factor

See Also
  wheelFactor(), setWheelButtonState(), setMouseFactor(), setKeyFactor()

void QwtMagnifier::setWheelModifiers | ( | Qt::KeyboardModifiers | modifiers | ) |

Assign keyboard modifiers for zooming in/out using the wheel. The default modifiers are Qt::NoModifiers.

Parameters

  modifiers | Keyboard modifiers

See Also
  wheelModifiers()

void QwtMagnifier::setZoomInKey | ( | int | key,
|  | Qt::KeyboardModifiers | modifiers = `Qt::NoModifier`
| ) |  |

Assign the key, that is used for zooming in. The default combination is Qt::Key_Plus + Qt::NoModifier.

Parameters

  key |
  modifiers |

See Also
  getZoomInKey(), setZoomOutKey()

void QwtMagnifier::setZoomOutKey | ( | int | key,
|  | Qt::KeyboardModifiers | modifiers = `Qt::NoModifier`
| ) |  |

Assign the key, that is used for zooming out. The default combination is Qt::Key_Minus + Qt::NoModifier.

Parameters

  key |
  modifiers |

See Also
  getZoomOutKey(), setZoomOutKey()

double QwtMagnifier::wheelFactor | ( |  | ) | const

Returns
  Wheel factor

See Also
  setWheelFactor()

Qt::KeyboardModifiers QwtMagnifier::wheelModifiers | ( |  | ) | const

Returns
  Wheel modifiers

See Also
  setWheelModifiers()

void QwtMagnifier::widgetKeyPressEvent | ( | QKeyEvent * | keyEvent | ) |
| protected virtual

Handle a key press event for the observed widget.

Parameters

  keyEvent | Key event

See Also
  eventFilter(), widgetKeyReleaseEvent()

void QwtMagnifier::widgetKeyReleaseEvent | ( | QKeyEvent * | keyEvent | ) |
| protected virtual

Handle a key release event for the observed widget.

Parameters

  keyEvent | Key event

See Also
  eventFilter(), widgetKeyReleaseEvent()

void QwtMagnifier::widgetMouseMoveEvent | ( | QMouseEvent * | mouseEvent | ) |
| protected virtual

Handle a mouse move event for the observed widget.

Parameters

  mouseEvent | Mouse event

See Also
  eventFilter(), widgetMousePressEvent(), widgetMouseReleaseEvent(),

void QwtMagnifier::widgetMousePressEvent | ( | QMouseEvent * | mouseEvent | ) |
| protected virtual

Handle a mouse press event for the observed widget.

Parameters

  mouseEvent | Mouse event

See Also
  eventFilter(), widgetMouseReleaseEvent(), widgetMouseMoveEvent()

void QwtMagnifier::widgetMouseReleaseEvent | ( | QMouseEvent * | mouseEvent | ) |
| protected virtual

Handle a mouse release event for the observed widget.

Parameters

  mouseEvent | Mouse event

See Also
  eventFilter(), widgetMousePressEvent(), widgetMouseMoveEvent(),

void QwtMagnifier::widgetWheelEvent | ( | QWheelEvent * | wheelEvent | ) |
| protected virtual

Handle a wheel event for the observed widget.

Parameters

  wheelEvent | Wheel event

See Also
  eventFilter()