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NAME

       QwtPlotRescaler - QwtPlotRescaler takes care of fixed aspect ratios for plot scales.

SYNOPSIS

       #include <qwt_plot_rescaler.h>

       Inherits QObject.

   Public Types
       enum RescalePolicy { Fixed, Expanding, Fitting }
       enum ExpandingDirection { ExpandUp, ExpandDown, ExpandBoth }

   Public Member Functions
       QwtPlotRescaler (QWidget *canvas, int referenceAxis=QwtPlot::xBottom,
           RescalePolicy=Expanding)
       virtual ~QwtPlotRescaler ()
           Destructor.
       void setEnabled (bool)
           En/disable the rescaler.
       bool isEnabled () const
       void setRescalePolicy (RescalePolicy)
       RescalePolicy rescalePolicy () const
       void setExpandingDirection (ExpandingDirection)
       void setExpandingDirection (int axis, ExpandingDirection)
       ExpandingDirection expandingDirection (int axis) const
       void setReferenceAxis (int axis)
       int referenceAxis () const
       void setAspectRatio (double ratio)
       void setAspectRatio (int axis, double ratio)
       double aspectRatio (int axis) const
       void setIntervalHint (int axis, const QwtInterval &)
       QwtInterval intervalHint (int axis) const
       QWidget * canvas ()
       const QWidget * canvas () const
       QwtPlot * plot ()
       const QwtPlot * plot () const
       virtual bool eventFilter (QObject *, QEvent *)
           Event filter for the plot canvas.
       void rescale () const
           Adjust the plot axes scales.

   Protected Member Functions
       virtual void canvasResizeEvent (QResizeEvent *)
       virtual void rescale (const QSize &oldSize, const QSize &newSize) const
       virtual QwtInterval expandScale (int axis, const QSize &oldSize, const QSize &newSize)
           const
       virtual QwtInterval syncScale (int axis, const QwtInterval &reference, const QSize &size)
           const
       virtual void updateScales (QwtInterval intervals[QwtPlot::axisCnt]) const
       Qt::Orientation orientation (int axis) const
       QwtInterval interval (int axis) const
       QwtInterval expandInterval (const QwtInterval &, double width, ExpandingDirection) const

Detailed Description

       QwtPlotRescaler takes care of fixed aspect ratios for plot scales.

       QwtPlotRescaler auto adjusts the axes of a QwtPlot according to fixed aspect ratios.

Member Enumeration Documentation

   enum QwtPlotRescaler::ExpandingDirection
       When rescalePolicy() is set to Expanding its direction depends on ExpandingDirection

       Enumerator

       ExpandUp
              The upper limit of the scale is adjusted.

       ExpandDown
              The lower limit of the scale is adjusted.

       ExpandBoth
              Both limits of the scale are adjusted.

   enum QwtPlotRescaler::RescalePolicy
       The rescale policy defines how to rescale the reference axis and their depending axes.

       See also:
           ExpandingDirection, setIntervalHint()

       Enumerator

       Fixed  The interval of the reference axis remains unchanged, when the geometry of the
              canvas changes. All other axes will be adjusted according to their aspect ratio.

       Expanding
              The interval of the reference axis will be shrunk/expanded, when the geometry of
              the canvas changes. All other axes will be adjusted according to their aspect
              ratio.

       The interval, that is represented by one pixel is fixed.

       Fitting
              The intervals of the axes are calculated, so that all axes include their interval
              hint.

Constructor & Destructor Documentation

   QwtPlotRescaler::QwtPlotRescaler (QWidget * canvas, int referenceAxis = QwtPlot::xBottom,
       RescalePolicy policy = Expanding) [explicit]
       Constructor

       Parameters:
           canvas Canvas
           referenceAxis Reference axis, see RescalePolicy
           policy Rescale policy

       See also:
           setRescalePolicy(), setReferenceAxis()

Member Function Documentation

   double QwtPlotRescaler::aspectRatio (int axis) const
       Returns:
           Aspect ratio between an axis and the reference axis.

       Parameters:
           axis Axis index ( see QwtPlot::AxisId )

       See also:
           setAspectRatio()

   QWidget * QwtPlotRescaler::canvas ()
       Returns:
           plot canvas

   const QWidget * QwtPlotRescaler::canvas () const
       Returns:
           plot canvas

   void QwtPlotRescaler::canvasResizeEvent (QResizeEvent * event) [protected],  [virtual]
       Event handler for resize events of the plot canvas

       Parameters:
           event Resize event

       See also:
           rescale()

   QwtPlotRescaler::ExpandingDirection QwtPlotRescaler::expandingDirection (int axis) const
       Returns:
           Direction in which an axis should be expanded

       Parameters:
           axis Axis index ( see QwtPlot::AxisId )

       See also:
           setExpandingDirection()

   QwtInterval QwtPlotRescaler::expandInterval (const QwtInterval & interval, double width,
       ExpandingDirection direction) const [protected]
       Expand the interval

       Parameters:
           interval Interval to be expanded
           width Distance to be added to the interval
           direction Direction of the expand operation

       Returns:
           Expanded interval

   QwtInterval QwtPlotRescaler::expandScale (int axis, const QSize & oldSize, const QSize &
       newSize) const [protected],  [virtual]
       Calculate the new scale interval of a plot axis

       Parameters:
           axis Axis index ( see QwtPlot::AxisId )
           oldSize Previous size of the canvas
           newSize New size of the canvas

       Returns:
           Calculated new interval for the axis

   QwtInterval QwtPlotRescaler::interval (int axis) const [protected]
       Parameters:
           axis Axis index ( see QwtPlot::AxisId )

       Returns:
           Normalized interval of an axis

   QwtInterval QwtPlotRescaler::intervalHint (int axis) const
       Parameters:
           axis Axis, see QwtPlot::Axis

       Returns:
           Interval hint

       See also:
           setIntervalHint(), RescalePolicy

   bool QwtPlotRescaler::isEnabled () const
       Returns:
           true when enabled, false otherwise

       See also:
           setEnabled, eventFilter()

   Qt::Orientation QwtPlotRescaler::orientation (int axis) const [protected]
       Returns:
           Orientation of an axis

       Parameters:
           axis Axis index ( see QwtPlot::AxisId )

   QwtPlot * QwtPlotRescaler::plot ()
       Returns:
           plot widget

   const QwtPlot * QwtPlotRescaler::plot () const
       Returns:
           plot widget

   int QwtPlotRescaler::referenceAxis () const
       Returns:
           Reference axis ( see RescalePolicy )

       See also:
           setReferenceAxis()

   void QwtPlotRescaler::rescale (const QSize & oldSize, const QSize & newSize) const
       [protected],  [virtual]
       Adjust the plot axes scales

       Parameters:
           oldSize Previous size of the canvas
           newSize New size of the canvas

   QwtPlotRescaler::RescalePolicy QwtPlotRescaler::rescalePolicy () const
       Returns:
           Rescale policy

       See also:
           setRescalePolicy()

   void QwtPlotRescaler::setAspectRatio (double ratio)
       Set the aspect ratio between the scale of the reference axis and the other scales. The
       default ratio is 1.0

       Parameters:
           ratio Aspect ratio

       See also:
           aspectRatio()

   void QwtPlotRescaler::setAspectRatio (int axis, double ratio)
       Set the aspect ratio between the scale of the reference axis and another scale. The
       default ratio is 1.0

       Parameters:
           axis Axis index ( see QwtPlot::AxisId )
           ratio Aspect ratio

       See also:
           aspectRatio()

   void QwtPlotRescaler::setEnabled (bool on)
       En/disable the rescaler. When enabled is true an event filter is installed for the canvas,
       otherwise the event filter is removed.

       Parameters:
           on true or false

       See also:
           isEnabled(), eventFilter()

   void QwtPlotRescaler::setExpandingDirection (ExpandingDirection direction)
       Set the direction in which all axis should be expanded

       Parameters:
           direction Direction

       See also:
           expandingDirection()

   void QwtPlotRescaler::setExpandingDirection (int axis, ExpandingDirection direction)
       Set the direction in which an axis should be expanded

       Parameters:
           axis Axis index ( see QwtPlot::AxisId )
           direction Direction

       See also:
           expandingDirection()

   void QwtPlotRescaler::setIntervalHint (int axis, const QwtInterval & interval)
       Set an interval hint for an axis

       In Fitting mode, the hint is used as minimal interval that always needs to be displayed.

       Parameters:
           axis Axis, see QwtPlot::Axis
           interval Axis

       See also:
           intervalHint(), RescalePolicy

   void QwtPlotRescaler::setReferenceAxis (int axis)
       Set the reference axis ( see RescalePolicy )

       Parameters:
           axis Axis index ( QwtPlot::Axis )

       See also:
           referenceAxis()

   void QwtPlotRescaler::setRescalePolicy (RescalePolicy policy)
       Change the rescale policy

       Parameters:
           policy Rescale policy

       See also:
           rescalePolicy()

   QwtInterval QwtPlotRescaler::syncScale (int axis, const QwtInterval & reference, const QSize &
       size) const [protected],  [virtual]
       Synchronize an axis scale according to the scale of the reference axis

       Parameters:
           axis Axis index ( see QwtPlot::AxisId )
           reference Interval of the reference axis
           size Size of the canvas

       Returns:
           New interval for axis

   void QwtPlotRescaler::updateScales (QwtInterval intervals[QwtPlot::axisCnt]) const
       [protected],  [virtual]
       Update the axes scales

       Parameters:
           intervals Scale intervals

Author

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