Qwt User's Guide: QwtPlot Class Reference

Qwt User's Guide 6.3.0

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Public Types | Public Slots | Signals | Public Member Functions | Protected Member Functions | List of all members
QwtPlot Class Reference

A 2-D plotting widget. More...

`#include <qwt_plot.h>`

Inheritance diagram for QwtPlot:

## Public Types
enum | LegendPosition { LeftLegend , RightLegend , BottomLegend , TopLegend }

## Public Slots
virtual void | replot ()
| Redraw the plot.
void | autoRefresh ()
| Replots the plot if autoReplot() is `true`.

## Signals
void | itemAttached (QwtPlotItem *plotItem, bool on)
void | legendDataChanged (const QVariant &itemInfo, const QList< QwtLegendData > &data)

## Public Member Functions
| QwtPlot (QWidget *=NULL)
| Constructor.
| QwtPlot (const QwtText &title, QWidget *=NULL)
| Constructor.
virtual | ~QwtPlot ()
| Destructor.
void | setAutoReplot (bool=true)
| Set or reset the autoReplot option.
bool | autoReplot () const
void | setPlotLayout (QwtPlotLayout *)
| Assign a new plot layout.
QwtPlotLayout * | plotLayout ()
const QwtPlotLayout * | plotLayout () const
void | setTitle (const QString &)
void | setTitle (const QwtText &)
QwtText | title () const
QwtTextLabel * | titleLabel ()
const QwtTextLabel * | titleLabel () const
void | setFooter (const QString &)
void | setFooter (const QwtText &)
QwtText | footer () const
QwtTextLabel * | footerLabel ()
const QwtTextLabel * | footerLabel () const
void | setCanvas (QWidget *)
| Set the drawing canvas of the plot widget.
QWidget * | canvas ()
const QWidget * | canvas () const
void | setCanvasBackground (const QBrush &)
| Change the background of the plotting area.
QBrush | canvasBackground () const
virtual QwtScaleMap | canvasMap (QwtAxisId) const
double | invTransform (QwtAxisId, double pos) const
double | transform (QwtAxisId, double value) const
| Transform a value into a coordinate in the plotting region.
bool | isAxisValid (QwtAxisId) const
void | setAxisVisible (QwtAxisId, bool on=true)
| Hide or show a specified axis.
bool | isAxisVisible (QwtAxisId) const
QwtScaleEngine * | axisScaleEngine (QwtAxisId)
const QwtScaleEngine * | axisScaleEngine (QwtAxisId) const
void | setAxisScaleEngine (QwtAxisId, QwtScaleEngine *)
void | setAxisAutoScale (QwtAxisId, bool on=true)
| Enable autoscaling for a specified axis.
bool | axisAutoScale (QwtAxisId) const
void | setAxisFont (QwtAxisId, const QFont &)
| Change the font of an axis.
QFont | axisFont (QwtAxisId) const
void | setAxisScale (QwtAxisId, double min, double max, double stepSize=0)
| Disable autoscaling and specify a fixed scale for a selected axis.
void | setAxisScaleDiv (QwtAxisId, const QwtScaleDiv &)
| Disable autoscaling and specify a fixed scale for a selected axis.
void | setAxisScaleDraw (QwtAxisId, QwtScaleDraw *)
| Set a scale draw.
double | axisStepSize (QwtAxisId) const
| Return the step size parameter that has been set in setAxisScale.
QwtInterval | axisInterval (QwtAxisId) const
| Return the current interval of the specified axis.
const QwtScaleDiv & | axisScaleDiv (QwtAxisId) const
| Return the scale division of a specified axis.
const QwtScaleDraw * | axisScaleDraw (QwtAxisId) const
| Return the scale draw of a specified axis.
QwtScaleDraw * | axisScaleDraw (QwtAxisId)
| Return the scale draw of a specified axis.
const QwtScaleWidget * | axisWidget (QwtAxisId) const
QwtScaleWidget * | axisWidget (QwtAxisId)
void | setAxisLabelAlignment (QwtAxisId, Qt::Alignment)
void | setAxisLabelRotation (QwtAxisId, double rotation)
void | setAxisTitle (QwtAxisId, const QString &)
| Change the title of a specified axis.
void | setAxisTitle (QwtAxisId, const QwtText &)
| Change the title of a specified axis.
QwtText | axisTitle (QwtAxisId) const
void | setAxisMaxMinor (QwtAxisId, int maxMinor)
int | axisMaxMinor (QwtAxisId) const
void | setAxisMaxMajor (QwtAxisId, int maxMajor)
int | axisMaxMajor (QwtAxisId) const
void | insertLegend (QwtAbstractLegend *, LegendPosition=QwtPlot::RightLegend, double ratio=-1.0)
| Insert a legend.
QwtAbstractLegend * | legend ()
const QwtAbstractLegend * | legend () const
void | updateLegend ()
void | updateLegend (const QwtPlotItem *)
virtual QSize | sizeHint () const override
virtual QSize | minimumSizeHint () const override
| Return a minimum size hint.
virtual void | updateLayout ()
| Adjust plot content to its current size.
virtual void | drawCanvas (QPainter *)
void | updateAxes ()
| Rebuild the axes scales.
void | updateCanvasMargins ()
| Update the canvas margins.
virtual void | getCanvasMarginsHint (const QwtScaleMap maps[], const QRectF &canvasRect, double &left, double &top, double &right, double &bottom) const
| Calculate the canvas margins.
virtual bool | event (QEvent *) override
| Adds handling of layout requests.
virtual bool | eventFilter (QObject *, QEvent *) override
| Event filter.
virtual void | drawItems (QPainter *, const QRectF &, const QwtScaleMap maps[QwtAxis::AxisPositions]) const
virtual QVariant | itemToInfo (QwtPlotItem *) const
| Build an information, that can be used to identify a plot item on the legend.
virtual QwtPlotItem * | infoToItem (const QVariant &) const
| Identify the plot item according to an item info object, that has bee generated from itemToInfo().
Public Member Functions inherited from QwtPlotDict
| QwtPlotDict ()
virtual | ~QwtPlotDict ()
void | setAutoDelete (bool)
bool | autoDelete () const
const QwtPlotItemList & | itemList () const
| A QwtPlotItemList of all attached plot items.
QwtPlotItemList | itemList (int rtti) const
void | detachItems (int rtti=QwtPlotItem::Rtti_PlotItem, bool autoDelete=true)

## Protected Member Functions
virtual void | resizeEvent (QResizeEvent *) override
Protected Member Functions inherited from QwtPlotDict
void | insertItem (QwtPlotItem *)
void | removeItem (QwtPlotItem *)

## Detailed Description

A 2-D plotting widget.

QwtPlot is a widget for plotting two-dimensional graphs. An unlimited number of plot items can be displayed on its canvas. Plot items might be curves (QwtPlotCurve), markers (QwtPlotMarker), the grid (QwtPlotGrid), or anything else derived from QwtPlotItem. A plot can have up to four axes, with each plot item attached to an x- and a y axis. The scales at the axes can be explicitly set (QwtScaleDiv), or are calculated from the plot items, using algorithms (QwtScaleEngine) which can be configured separately for each axis.

The simpleplot example is a good starting point to see how to set up a plot widget.

Example
  The following example shows (schematically) the most simple way to use QwtPlot. By default, only the left and bottom axes are visible and their scales are computed automatically.
  #include <qwt_plot.h>
  #include <qwt_plot_curve.h>
  QwtPlot *myPlot = new QwtPlot( "Two Curves", parent );
  // add curves
  QwtPlotCurve *curve1 = new QwtPlotCurve( "Curve 1" );
  QwtPlotCurve *curve2 = new QwtPlotCurve( "Curve 2" );
  // connect or copy the data to the curves
  curve1->setData( ... );
  curve2->setData( ... );
  curve1->attach( myPlot );
  curve2->attach( myPlot );
  // finally, refresh the plot
  myPlot->replot();
  QwtPlotCurve
  A plot item, that represents a series of points.
  Definition qwt_plot_curve.h:59
  QwtPlot
  A 2-D plotting widget.
  Definition qwt_plot.h:79
  QwtPlot::replot
  virtual void replot()
  Redraw the plot.
  Definition qwt_plot.cpp:545
  QwtPlot::QwtPlot
  QwtPlot(QWidget *=NULL)
  Constructor.
  Definition qwt_plot.cpp:103
  QwtPlotItem::attach
  void attach(QwtPlot *plot)
  Attach the item to a plot.
  Definition qwt_plot_item.cpp:98
  QwtSeriesStore::setData
  void setData(QwtSeriesData< T > *series)
  Definition qwt_series_store.h:164

Definition at line 78 of file qwt_plot.h.

## Member Enumeration Documentation

## ◆ LegendPosition

enum QwtPlot::LegendPosition

Position of the legend, relative to the canvas.

See also
  insertLegend()

Enumerator
LeftLegend | The legend will be left from the QwtAxis::YLeft axis.
RightLegend | The legend will be right from the QwtAxis::YRight axis.
BottomLegend | The legend will be below the footer.
TopLegend | The legend will be above the title.

Definition at line 93 of file qwt_plot.h.

## Constructor & Destructor Documentation

## ◆ QwtPlot() [1/2]

QwtPlot::QwtPlot | ( | QWidget * | parent = NULL | ) |
| explicit

Constructor.

Parameters

  parent | Parent widget

Definition at line 103 of file qwt_plot.cpp.

## ◆ QwtPlot() [2/2]

QwtPlot::QwtPlot | ( | const QwtText & | title,
|  | QWidget * | parent = NULL )
| explicit

Constructor.

Parameters

  title | Title text
  parent | Parent widget

Definition at line 114 of file qwt_plot.cpp.

## ◆ ~QwtPlot()

QwtPlot::~QwtPlot | ( |  | ) |
| virtual

Destructor.

Definition at line 121 of file qwt_plot.cpp.

## Member Function Documentation

## ◆ autoRefresh

void QwtPlot::autoRefresh | ( |  | ) |
| slot

Replots the plot if autoReplot() is `true`.

Definition at line 289 of file qwt_plot.cpp.

## ◆ autoReplot()

bool QwtPlot::autoReplot | ( |  | ) | const

Returns
  true if the autoReplot option is set.

See also
  setAutoReplot()

Definition at line 319 of file qwt_plot.cpp.

## ◆ axisAutoScale()

bool QwtPlot::axisAutoScale | ( | QwtAxisId | axisId | ) | const

Returns
  `True`, if autoscaling is enabled

Parameters

  axisId | Axis

Definition at line 213 of file qwt_plot_axis.cpp.

## ◆ axisFont()

QFont QwtPlot::axisFont | ( | QwtAxisId | axisId | ) | const

Returns
  The font of the scale labels for a specified axis

Parameters

  axisId | Axis

Definition at line 237 of file qwt_plot_axis.cpp.

## ◆ axisInterval()

QwtInterval QwtPlot::axisInterval | ( | QwtAxisId | axisId | ) | const

Return the current interval of the specified axis.

This is only a convenience function for axisScaleDiv( axisId )->interval();

Parameters

  axisId | Axis

Returns
  Scale interval

See also
  QwtScaleDiv, axisScaleDiv()

Definition at line 348 of file qwt_plot_axis.cpp.

## ◆ axisMaxMajor()

int QwtPlot::axisMaxMajor | ( | QwtAxisId | axisId | ) | const

Returns
  The maximum number of major ticks for a specified axis

Parameters

  axisId | Axis

See also
  setAxisMaxMajor(), QwtScaleEngine::divideScale()

Definition at line 251 of file qwt_plot_axis.cpp.

## ◆ axisMaxMinor()

int QwtPlot::axisMaxMinor | ( | QwtAxisId | axisId | ) | const

Returns
  the maximum number of minor ticks for a specified axis

Parameters

  axisId | Axis

See also
  setAxisMaxMinor(), QwtScaleEngine::divideScale()

Definition at line 264 of file qwt_plot_axis.cpp.

## ◆ axisScaleDiv()

const QwtScaleDiv & QwtPlot::axisScaleDiv | ( | QwtAxisId | axisId | ) | const

Return the scale division of a specified axis.

axisScaleDiv(axisId).lowerBound(), axisScaleDiv(axisId).upperBound() are the current limits of the axis scale.

Parameters

  axisId | Axis

Returns
  Scale division

See also
  QwtScaleDiv, setAxisScaleDiv(), QwtScaleEngine::divideScale()

Definition at line 283 of file qwt_plot_axis.cpp.

## ◆ axisScaleDraw() [1/2]

QwtScaleDraw * QwtPlot::axisScaleDraw | ( | QwtAxisId | axisId | ) |

Return the scale draw of a specified axis.

Parameters

  axisId | Axis

Returns
  Specified scaleDraw for axis, or NULL if axis is invalid.

Definition at line 312 of file qwt_plot_axis.cpp.

## ◆ axisScaleDraw() [2/2]

const QwtScaleDraw * QwtPlot::axisScaleDraw | ( | QwtAxisId | axisId | ) | const

Return the scale draw of a specified axis.

Parameters

  axisId | Axis

Returns
  Specified scaleDraw for axis, or NULL if axis is invalid.

Definition at line 298 of file qwt_plot_axis.cpp.

## ◆ axisScaleEngine() [1/2]

QwtScaleEngine * QwtPlot::axisScaleEngine | ( | QwtAxisId | axisId | ) |

Parameters

  axisId | Axis

Returns
  Scale engine for a specific axis

Definition at line 190 of file qwt_plot_axis.cpp.

## ◆ axisScaleEngine() [2/2]

const QwtScaleEngine * QwtPlot::axisScaleEngine | ( | QwtAxisId | axisId | ) | const

Parameters

  axisId | Axis

Returns
  Scale engine for a specific axis

Definition at line 202 of file qwt_plot_axis.cpp.

## ◆ axisStepSize()

double QwtPlot::axisStepSize | ( | QwtAxisId | axisId | ) | const

Return the step size parameter that has been set in setAxisScale.

This doesn't need to be the step size of the current scale.

Parameters

  axisId | Axis

Returns
  step size parameter value

See also
  setAxisScale(), QwtScaleEngine::divideScale()

Definition at line 330 of file qwt_plot_axis.cpp.

## ◆ axisTitle()

QwtText QwtPlot::axisTitle | ( | QwtAxisId | axisId | ) | const

Returns
  Title of a specified axis

Parameters

  axisId | Axis

Definition at line 360 of file qwt_plot_axis.cpp.

## ◆ axisWidget() [1/2]

QwtScaleWidget * QwtPlot::axisWidget | ( | QwtAxisId | axisId | ) |

Returns
  Scale widget of the specified axis, or NULL if axisId is invalid.

Parameters

  axisId | Axis

Definition at line 153 of file qwt_plot_axis.cpp.

## ◆ axisWidget() [2/2]

const QwtScaleWidget * QwtPlot::axisWidget | ( | QwtAxisId | axisId | ) | const

Returns
  Scale widget of the specified axis, or NULL if axisId is invalid.

Parameters

  axisId | Axis

Definition at line 141 of file qwt_plot_axis.cpp.

## ◆ canvas() [1/2]

QWidget * QwtPlot::canvas | ( |  | ) |

Returns
  the plot's canvas

Definition at line 463 of file qwt_plot.cpp.

## ◆ canvas() [2/2]

const QWidget * QwtPlot::canvas | ( |  | ) | const

Returns
  the plot's canvas

Definition at line 471 of file qwt_plot.cpp.

## ◆ canvasBackground()

QBrush QwtPlot::canvasBackground | ( |  | ) | const

Nothing else than: canvas()->palette().brush( QPalette::Normal, QPalette::Window);

Returns
  Background brush of the plotting area.

See also
  setCanvasBackground()

Definition at line 888 of file qwt_plot.cpp.

## ◆ canvasMap()

QwtScaleMap QwtPlot::canvasMap | ( | QwtAxisId | axisId | ) | const
| virtual

Parameters

  axisId | Axis

Returns
  Map for the axis on the canvas. With this map pixel coordinates can translated to plot coordinates and vice versa.

See also
  QwtScaleMap, transform(), invTransform()

Definition at line 800 of file qwt_plot.cpp.

## ◆ drawCanvas()

void QwtPlot::drawCanvas | ( | QPainter * | painter | ) |
| virtual

Redraw the canvas.

Parameters

  painter | Painter used for drawing

Warning
  drawCanvas calls drawItems what is also used for printing. Applications that like to add individual plot items better overload drawItems()

See also
  drawItems()

Definition at line 742 of file qwt_plot.cpp.

## ◆ drawItems()

void QwtPlot::drawItems | ( | QPainter * | painter,
|  | const QRectF & | canvasRect,
|  | const QwtScaleMap | maps[QwtAxis::AxisPositions] ) const
| virtual

Redraw the canvas items.

Parameters

  painter | Painter used for drawing
  canvasRect | Bounding rectangle where to paint
  maps | QwtAxis::AxisCount maps, mapping between plot and paint device coordinates

Note
  Usually canvasRect is contentsRect() of the plot canvas. Due to a bug in Qt this rectangle might be wrong for certain frame styles ( f.e QFrame::Box ) and it might be necessary to fix the margins manually using QWidget::setContentsMargins()

Definition at line 764 of file qwt_plot.cpp.

## ◆ event()

bool QwtPlot::event | ( | QEvent * | event | ) |
| overridevirtual

Adds handling of layout requests.

Parameters

  event | Event

Returns
  See QFrame::event()

Definition at line 237 of file qwt_plot.cpp.

## ◆ eventFilter()

bool QwtPlot::eventFilter | ( | QObject * | object,
|  | QEvent * | event )
| overridevirtual

Event filter.

The plot handles the following events for the canvas:

- QEvent::Resize The canvas margins might depend on its size
- QEvent::ContentsRectChange The layout needs to be recalculated

Parameters

  object | Object to be filtered
  event | Event

Returns
  See QFrame::eventFilter()

See also
  updateCanvasMargins(), updateLayout()

Definition at line 271 of file qwt_plot.cpp.

## ◆ footer()

QwtText QwtPlot::footer | ( |  | ) | const

Returns
  Text of the footer

Definition at line 395 of file qwt_plot.cpp.

## ◆ footerLabel() [1/2]

QwtTextLabel * QwtPlot::footerLabel | ( |  | ) |

Returns
  Footer label widget.

Definition at line 401 of file qwt_plot.cpp.

## ◆ footerLabel() [2/2]

const QwtTextLabel * QwtPlot::footerLabel | ( |  | ) | const

Returns
  Footer label widget.

Definition at line 407 of file qwt_plot.cpp.

## ◆ getCanvasMarginsHint()

void QwtPlot::getCanvasMarginsHint | ( | const QwtScaleMap | maps[],
|  | const QRectF & | canvasRect,
|  | double & | left,
|  | double & | top,
|  | double & | right,
|  | double & | bottom ) const
| virtual

Calculate the canvas margins.

Parameters

  maps | QwtAxis::AxisCount maps, mapping between plot and paint device coordinates
  canvasRect | Bounding rectangle where to paint
  left | Return parameter for the left margin
  top | Return parameter for the top margin
  right | Return parameter for the right margin
  bottom | Return parameter for the bottom margin

Plot items might indicate, that they need some extra space at the borders of the canvas by the QwtPlotItem::Margins flag.

updateCanvasMargins(), QwtPlotItem::getCanvasMarginHint()

Definition at line 670 of file qwt_plot.cpp.

## ◆ infoToItem()

QwtPlotItem * QwtPlot::infoToItem | ( | const QVariant & | itemInfo | ) | const
| virtual

Identify the plot item according to an item info object, that has bee generated from itemToInfo().

The default implementation simply tries to unwrap a QwtPlotItem pointer:

if ( itemInfo.canConvert<QwtPlotItem *>() )
return qvariant_cast<QwtPlotItem *>( itemInfo );
QwtPlotItem
Base class for items on the plot canvas.
Definition qwt_plot_item.h:67

Parameters

  itemInfo | Plot item

Returns
  A plot item, when successful, otherwise a NULL pointer.

See also
  itemToInfo()

Definition at line 1159 of file qwt_plot.cpp.

## ◆ insertLegend()

void QwtPlot::insertLegend | ( | QwtAbstractLegend * | legend,
|  | QwtPlot::LegendPosition | pos = QwtPlot::RightLegend,
|  | double | ratio = -1.0 )

Insert a legend.

If the position legend is `QwtPlot::LeftLegend` or `QwtPlot::RightLegend` the legend will be organized in one column from top to down. Otherwise the legend items will be placed in a table with a best fit number of columns from left to right.

insertLegend() will set the plot widget as parent for the legend. The legend will be deleted in the destructor of the plot or when another legend is inserted.

Legends, that are not inserted into the layout of the plot widget need to connect to the legendDataChanged() signal. Calling updateLegend() initiates this signal for an initial update. When the application code wants to implement its own layout this also needs to be done for rendering plots to a document ( see QwtPlotRenderer ).

Parameters

  legend | Legend
  pos | The legend's position. For top/left position the number of columns will be limited to 1, otherwise it will be set to unlimited.
  ratio | Ratio between legend and the bounding rectangle of title, canvas and axes. The legend will be shrunk if it would need more space than the given ratio. The ratio is limited to ]0.0 .. 1.0]. In case of <= 0.0 it will be reset to the default ratio. The default vertical/horizontal ratio is 0.33/0.5.

See also
  legend(), QwtPlotLayout::legendPosition(), QwtPlotLayout::setLegendPosition()

Definition at line 927 of file qwt_plot.cpp.

## ◆ invTransform()

double QwtPlot::invTransform | ( | QwtAxisId | axisId,
|  | double | pos ) const

Transform the x or y coordinate of a position in the drawing region into a value.

Parameters

  axisId | Axis
  pos | position

Returns
  Position as axis coordinate

Warning
  The position can be an x or a y coordinate, depending on the specified axis.

Definition at line 401 of file qwt_plot_axis.cpp.

## ◆ isAxisValid()

bool QwtPlot::isAxisValid | ( | QwtAxisId | axisId | ) | const

Checks if an axis is valid

Parameters

  axisId | axis

Returns
  `true` if the specified axis exists, otherwise `false`

Note
  This method is equivalent to QwtAxis::isValid( axisId ) and simply checks if axisId is one of the values of QwtAxis::Position. It is a placeholder for future releases, where it will be possible to have a customizable number of axes ( multiaxes branch ) at each side.

Definition at line 132 of file qwt_plot_axis.cpp.

## ◆ isAxisVisible()

bool QwtPlot::isAxisVisible | ( | QwtAxisId | axisId | ) | const

Returns
  `True`, if a specified axis is visible

Parameters

  axisId | Axis

Definition at line 225 of file qwt_plot_axis.cpp.

## ◆ itemAttached

void QwtPlot::itemAttached | ( | QwtPlotItem * | plotItem,
|  | bool | on )
| signal

A signal indicating, that an item has been attached/detached

Parameters

  plotItem | Plot item
  on | Attached/Detached

## ◆ itemToInfo()

QVariant QwtPlot::itemToInfo | ( | QwtPlotItem * | plotItem | ) | const
| virtual

Build an information, that can be used to identify a plot item on the legend.

The default implementation simply wraps the plot item into a QVariant object. When overloading itemToInfo() usually infoToItem() needs to reimplemeted too.

Parameters

  plotItem | Plot item

Returns
  Plot item embedded in a QVariant

See also
  infoToItem()

Definition at line 1139 of file qwt_plot.cpp.

## ◆ legend() [1/2]

QwtAbstractLegend * QwtPlot::legend | ( |  | ) |

Returns
  the plot's legend

See also
  insertLegend()

Definition at line 445 of file qwt_plot.cpp.

## ◆ legend() [2/2]

const QwtAbstractLegend * QwtPlot::legend | ( |  | ) | const

Returns
  the plot's legend

See also
  insertLegend()

Definition at line 454 of file qwt_plot.cpp.

## ◆ legendDataChanged

void QwtPlot::legendDataChanged | ( | const QVariant & | itemInfo,
|  | const QList< QwtLegendData > & | data )
| signal

A signal with the attributes how to update the legend entries for a plot item.

Parameters

  itemInfo | Info about a plot item, build from itemToInfo()
  data | Attributes of the entries ( usually <= 1 ) for the plot item.

See also
  itemToInfo(), infoToItem(), QwtAbstractLegend::updateLegend()

## ◆ minimumSizeHint()

QSize QwtPlot::minimumSizeHint | ( |  | ) | const
| overridevirtual

Return a minimum size hint.

Definition at line 518 of file qwt_plot.cpp.

## ◆ plotLayout() [1/2]

QwtPlotLayout * QwtPlot::plotLayout | ( |  | ) |

Returns
  the plot's layout

Definition at line 430 of file qwt_plot.cpp.

## ◆ plotLayout() [2/2]

const QwtPlotLayout * QwtPlot::plotLayout | ( |  | ) | const

Returns
  the plot's layout

Definition at line 436 of file qwt_plot.cpp.

## ◆ replot

void QwtPlot::replot | ( |  | ) |
| virtualslot

Redraw the plot.

If the autoReplot option is not set (which is the default) or if any curves are attached to raw data, the plot has to be refreshed explicitly in order to make changes visible.

See also
  updateAxes(), setAutoReplot()

Definition at line 545 of file qwt_plot.cpp.

## ◆ resizeEvent()

void QwtPlot::resizeEvent | ( | QResizeEvent * | e | ) |
| overrideprotectedvirtual

Resize and update internal layout

Parameters

  e | Resize event

Definition at line 530 of file qwt_plot.cpp.

## ◆ setAutoReplot()

void QwtPlot::setAutoReplot | ( | bool | tf = true | ) |

Set or reset the autoReplot option.

If the autoReplot option is set, the plot will be updated implicitly by manipulating member functions. Since this may be time-consuming, it is recommended to leave this option switched off and call replot() explicitly if necessary.

The autoReplot option is set to false by default, which means that the user has to call replot() in order to make changes visible.

Parameters

  tf | `true` or `false`. Defaults to `true`.

See also
  replot()

Definition at line 310 of file qwt_plot.cpp.

## ◆ setAxisAutoScale()

void QwtPlot::setAxisAutoScale | ( | QwtAxisId | axisId,
|  | bool | on = true )

Enable autoscaling for a specified axis.

This member function is used to switch back to autoscaling mode after a fixed scale has been set. Autoscaling is enabled by default.

Parameters

  axisId | Axis
  on | On/Off

See also
  setAxisScale(), setAxisScaleDiv(), updateAxes()

Note
  The autoscaling flag has no effect until updateAxes() is executed ( called by replot() ).

Definition at line 453 of file qwt_plot_axis.cpp.

## ◆ setAxisFont()

void QwtPlot::setAxisFont | ( | QwtAxisId | axisId,
|  | const QFont & | font )

Change the font of an axis.

Parameters

  axisId | Axis
  font | Font

Warning
  This function changes the font of the tick labels, not of the axis title.

Definition at line 434 of file qwt_plot_axis.cpp.

## ◆ setAxisLabelAlignment()

void QwtPlot::setAxisLabelAlignment | ( | QwtAxisId | axisId,
|  | Qt::Alignment | alignment )

Change the alignment of the tick labels

Parameters

  axisId | Axis
  alignment | Or'd Qt::AlignmentFlags see <qnamespace.h>

See also
  QwtScaleDraw::setLabelAlignment()

Definition at line 553 of file qwt_plot_axis.cpp.

## ◆ setAxisLabelRotation()

void QwtPlot::setAxisLabelRotation | ( | QwtAxisId | axisId,
|  | double | rotation )

Rotate all tick labels

Parameters

  axisId | Axis
  rotation | Angle in degrees. When changing the label rotation, the label alignment might be adjusted too.

See also
  QwtScaleDraw::setLabelRotation(), setAxisLabelAlignment()

Definition at line 568 of file qwt_plot_axis.cpp.

## ◆ setAxisMaxMajor()

void QwtPlot::setAxisMaxMajor | ( | QwtAxisId | axisId,
|  | int | maxMajor )

Set the maximum number of major scale intervals for a specified axis

Parameters

  axisId | Axis
  maxMajor | Maximum number of major steps

See also
  axisMaxMajor()

Definition at line 606 of file qwt_plot_axis.cpp.

## ◆ setAxisMaxMinor()

void QwtPlot::setAxisMaxMinor | ( | QwtAxisId | axisId,
|  | int | maxMinor )

Set the maximum number of minor scale intervals for a specified axis

Parameters

  axisId | Axis
  maxMinor | Maximum number of minor steps

See also
  axisMaxMinor()

Definition at line 582 of file qwt_plot_axis.cpp.

## ◆ setAxisScale()

void QwtPlot::setAxisScale | ( | QwtAxisId | axisId,
|  | double | min,
|  | double | max,
|  | double | stepSize = 0 )

Disable autoscaling and specify a fixed scale for a selected axis.

In updateAxes() the scale engine calculates a scale division from the specified parameters, that will be assigned to the scale widget. So updates of the scale widget usually happen delayed with the next replot.

Parameters

  axisId | Axis
  min | Minimum of the scale
  max | Maximum of the scale
  stepSize | Major step size. If `step == 0`, the step size is calculated automatically using the maxMajor setting.

See also
  setAxisMaxMajor(), setAxisAutoScale(), axisStepSize(), QwtScaleEngine::divideScale()

Definition at line 477 of file qwt_plot_axis.cpp.

## ◆ setAxisScaleDiv()

void QwtPlot::setAxisScaleDiv | ( | QwtAxisId | axisId,
|  | const QwtScaleDiv & | scaleDiv )

Disable autoscaling and specify a fixed scale for a selected axis.

The scale division will be stored locally only until the next call of updateAxes(). So updates of the scale widget usually happen delayed with the next replot.

Parameters

  axisId | Axis
  scaleDiv | Scale division

See also
  setAxisScale(), setAxisAutoScale()

Definition at line 506 of file qwt_plot_axis.cpp.

## ◆ setAxisScaleDraw()

void QwtPlot::setAxisScaleDraw | ( | QwtAxisId | axisId,
|  | QwtScaleDraw * | scaleDraw )

Set a scale draw.

Parameters

  axisId | Axis
  scaleDraw | Object responsible for drawing scales.

By passing scaleDraw it is possible to extend QwtScaleDraw functionality and let it take place in QwtPlot. Please note that scaleDraw has to be created with new and will be deleted by the corresponding QwtScale member ( like a child object ).

See also
  QwtScaleDraw, QwtScaleWidget

Warning
  The attributes of scaleDraw will be overwritten by those of the previous QwtScaleDraw.

Definition at line 536 of file qwt_plot_axis.cpp.

## ◆ setAxisScaleEngine()

void QwtPlot::setAxisScaleEngine | ( | QwtAxisId | axisId,
|  | QwtScaleEngine * | scaleEngine )

Change the scale engine for an axis

Parameters

  axisId | Axis
  scaleEngine | Scale engine

See also
  axisScaleEngine()

Definition at line 169 of file qwt_plot_axis.cpp.

## ◆ setAxisTitle() [1/2]

void QwtPlot::setAxisTitle | ( | QwtAxisId | axisId,
|  | const QString & | title )

Change the title of a specified axis.

Parameters

  axisId | Axis
  title | axis title

Definition at line 628 of file qwt_plot_axis.cpp.

## ◆ setAxisTitle() [2/2]

void QwtPlot::setAxisTitle | ( | QwtAxisId | axisId,
|  | const QwtText & | title )

Change the title of a specified axis.

Parameters

  axisId | Axis
  title | Axis title

Definition at line 640 of file qwt_plot_axis.cpp.

## ◆ setAxisVisible()

void QwtPlot::setAxisVisible | ( | QwtAxisId | axisId,
|  | bool | on = true )

Hide or show a specified axis.

Curves, markers and other items can be attached to hidden axes, and transformation of screen coordinates into values works as normal.

Only QwtAxis::XBottom and QwtAxis::YLeft are enabled by default.

Parameters

  axisId | Axis
  on | `true` (visible) or `false` (hidden)

Definition at line 380 of file qwt_plot_axis.cpp.

## ◆ setCanvas()

void QwtPlot::setCanvas | ( | QWidget * | canvas | ) |

Set the drawing canvas of the plot widget.

QwtPlot invokes methods of the canvas as meta methods ( see QMetaObject ). In opposite to using conventional C++ techniques like virtual methods they allow to use canvas implementations that are derived from QWidget or QGLWidget.

The following meta methods could be implemented:

- replot() When the canvas doesn't offer a replot method, QwtPlot calls update() instead.
- borderPath() The border path is necessary to clip the content of the canvas When the canvas doesn't have any special border ( f.e rounded corners ) it is o.k. not to implement this method.

The default canvas is a QwtPlotCanvas

Parameters

  canvas | Canvas Widget

See also
  canvas()

Definition at line 213 of file qwt_plot.cpp.

## ◆ setCanvasBackground()

void QwtPlot::setCanvasBackground | ( | const QBrush & | brush | ) |

Change the background of the plotting area.

Sets brush to QPalette::Window of all color groups of the palette of the canvas. Using canvas()->setPalette() is a more powerful way to set these colors.

Parameters

  brush | New background brush

See also
  canvasBackground()

Definition at line 873 of file qwt_plot.cpp.

## ◆ setFooter() [1/2]

void QwtPlot::setFooter | ( | const QString & | text | ) |

Change the text the footer

Parameters

  text | New text of the footer

Definition at line 372 of file qwt_plot.cpp.

## ◆ setFooter() [2/2]

void QwtPlot::setFooter | ( | const QwtText & | text | ) |

Change the text the footer

Parameters

  text | New text of the footer

Definition at line 385 of file qwt_plot.cpp.

## ◆ setPlotLayout()

void QwtPlot::setPlotLayout | ( | QwtPlotLayout * | layout | ) |

Assign a new plot layout.

Parameters

  layout | Layout()

See also
  plotLayout()

Definition at line 418 of file qwt_plot.cpp.

## ◆ setTitle() [1/2]

void QwtPlot::setTitle | ( | const QString & | title | ) |

Change the plot's title

Parameters

  title | New title

Definition at line 328 of file qwt_plot.cpp.

## ◆ setTitle() [2/2]

void QwtPlot::setTitle | ( | const QwtText & | title | ) |

Change the plot's title

Parameters

  title | New title

Definition at line 341 of file qwt_plot.cpp.

## ◆ sizeHint()

QSize QwtPlot::sizeHint | ( |  | ) | const
| overridevirtual

Returns
  Size hint for the plot widget

See also
  minimumSizeHint()

Definition at line 480 of file qwt_plot.cpp.

## ◆ title()

QwtText QwtPlot::title | ( |  | ) | const

Returns
  Title of the plot

Definition at line 351 of file qwt_plot.cpp.

## ◆ titleLabel() [1/2]

QwtTextLabel * QwtPlot::titleLabel | ( |  | ) |

Returns
  Title label widget.

Definition at line 357 of file qwt_plot.cpp.

## ◆ titleLabel() [2/2]

const QwtTextLabel * QwtPlot::titleLabel | ( |  | ) | const

Returns
  Title label widget.

Definition at line 363 of file qwt_plot.cpp.

## ◆ transform()

double QwtPlot::transform | ( | QwtAxisId | axisId,
|  | double | value ) const

Transform a value into a coordinate in the plotting region.

Parameters

  axisId | Axis
  value | value

Returns
  X or Y coordinate in the plotting region corresponding to the value.

Definition at line 418 of file qwt_plot_axis.cpp.

## ◆ updateAxes()

void QwtPlot::updateAxes | ( |  | ) |

Rebuild the axes scales.

In case of autoscaling the boundaries of a scale are calculated from the bounding rectangles of all plot items, having the QwtPlotItem::AutoScale flag enabled ( QwtScaleEngine::autoScale() ). Then a scale division is calculated ( QwtScaleEngine::didvideScale() ) and assigned to scale widget.

When the scale boundaries have been assigned with setAxisScale() a scale division is calculated ( QwtScaleEngine::didvideScale() ) for this interval and assigned to the scale widget.

When the scale has been set explicitly by setAxisScaleDiv() the locally stored scale division gets assigned to the scale widget.

The scale widget indicates modifications by emitting a QwtScaleWidget::scaleDivChanged() signal.

updateAxes() is usually called by replot().

See also
  setAxisAutoScale(), setAxisScale(), setAxisScaleDiv(), replot() QwtPlotItem::boundingRect()

Definition at line 670 of file qwt_plot_axis.cpp.

## ◆ updateCanvasMargins()

void QwtPlot::updateCanvasMargins | ( |  | ) |

Update the canvas margins.

Plot items might indicate, that they need some extra space at the borders of the canvas by the QwtPlotItem::Margins flag.

getCanvasMarginsHint(), QwtPlotItem::getCanvasMarginHint()

Definition at line 706 of file qwt_plot.cpp.

## ◆ updateLayout()

void QwtPlot::updateLayout | ( |  | ) |
| virtual

Adjust plot content to its current size.

See also
  resizeEvent()

Definition at line 577 of file qwt_plot.cpp.

## ◆ updateLegend() [1/2]

void QwtPlot::updateLegend | ( |  | ) |

Emit legendDataChanged() for all plot item

See also
  QwtPlotItem::legendData(), legendDataChanged()

Definition at line 1016 of file qwt_plot.cpp.

## ◆ updateLegend() [2/2]

void QwtPlot::updateLegend | ( | const QwtPlotItem * | plotItem | ) |

Emit legendDataChanged() for a plot item

Parameters

  plotItem | Plot item

See also
  QwtPlotItem::legendData(), legendDataChanged()

Definition at line 1032 of file qwt_plot.cpp.