QCustomPlot Class Reference
Author: Emanuel Eichhammer

· · · ·
Public Types | Public Functions | Public Members | Signals | Protected Functions
QCustomPlot Class Reference

The central class of the library. This is the QWidget which displays the plot and interacts with the user. More...

## Public Types
enum | LayerInsertMode
enum | RefreshPriority

## Public Functions
| QCustomPlot (QWidget *parent=nullptr)
QRect | viewport () const
double | bufferDevicePixelRatio () const
QPixmap | background () const
bool | backgroundScaled () const
Qt::AspectRatioMode | backgroundScaledMode () const
QCPLayoutGrid * | plotLayout () const
QCP::AntialiasedElements | antialiasedElements () const
QCP::AntialiasedElements | notAntialiasedElements () const
bool | autoAddPlottableToLegend () const
const QCP::Interactions | interactions () const
int | selectionTolerance () const
bool | noAntialiasingOnDrag () const
QCP::PlottingHints | plottingHints () const
Qt::KeyboardModifier | multiSelectModifier () const
QCP::SelectionRectMode | selectionRectMode () const
QCPSelectionRect * | selectionRect () const
bool | openGl () const
void | setViewport (const QRect &rect)
void | setBufferDevicePixelRatio (double ratio)
void | setBackground (const QPixmap &pm)
void | setBackground (const QPixmap &pm, bool scaled, Qt::AspectRatioMode mode=Qt::KeepAspectRatioByExpanding)
void | setBackground (const QBrush &brush)
void | setBackgroundScaled (bool scaled)
void | setBackgroundScaledMode (Qt::AspectRatioMode mode)
void | setAntialiasedElements (const QCP::AntialiasedElements &antialiasedElements)
void | setAntialiasedElement (QCP::AntialiasedElement antialiasedElement, bool enabled=true)
void | setNotAntialiasedElements (const QCP::AntialiasedElements &notAntialiasedElements)
void | setNotAntialiasedElement (QCP::AntialiasedElement notAntialiasedElement, bool enabled=true)
void | setAutoAddPlottableToLegend (bool on)
void | setInteractions (const QCP::Interactions &interactions)
void | setInteraction (const QCP::Interaction &interaction, bool enabled=true)
void | setSelectionTolerance (int pixels)
void | setNoAntialiasingOnDrag (bool enabled)
void | setPlottingHints (const QCP::PlottingHints &hints)
void | setPlottingHint (QCP::PlottingHint hint, bool enabled=true)
void | setMultiSelectModifier (Qt::KeyboardModifier modifier)
void | setSelectionRectMode (QCP::SelectionRectMode mode)
void | setSelectionRect (QCPSelectionRect *selectionRect)
void | setOpenGl (bool enabled, int multisampling=16)
QCPAbstractPlottable * | plottable (int index)
QCPAbstractPlottable * | plottable ()
bool | removePlottable (QCPAbstractPlottable *plottable)
bool | removePlottable (int index)
int | clearPlottables ()
int | plottableCount () const
QList< QCPAbstractPlottable * > | selectedPlottables () const
template<class PlottableType>
PlottableType * | plottableAt (const QPointF &pos, bool onlySelectable=false, int *dataIndex=nullptr) const
QCPAbstractPlottable * | plottableAt (const QPointF &pos, bool onlySelectable=false, int *dataIndex=nullptr) const
bool | hasPlottable (QCPAbstractPlottable *plottable) const
QCPGraph * | graph (int index) const
QCPGraph * | graph () const
QCPGraph * | addGraph (QCPAxis *keyAxis=nullptr, QCPAxis *valueAxis=nullptr)
bool | removeGraph (QCPGraph *graph)
bool | removeGraph (int index)
int | clearGraphs ()
int | graphCount () const
QList< QCPGraph * > | selectedGraphs () const
QCPAbstractItem * | item (int index) const
QCPAbstractItem * | item () const
bool | removeItem (QCPAbstractItem *item)
bool | removeItem (int index)
int | clearItems ()
int | itemCount () const
QList< QCPAbstractItem * > | selectedItems () const
template<class ItemType>
ItemType * | itemAt (const QPointF &pos, bool onlySelectable=false) const
QCPAbstractItem * | itemAt (const QPointF &pos, bool onlySelectable=false) const
bool | hasItem (QCPAbstractItem *item) const
QCPLayer * | layer (const QString &name) const
QCPLayer * | layer (int index) const
QCPLayer * | currentLayer () const
bool | setCurrentLayer (const QString &name)
bool | setCurrentLayer (QCPLayer *layer)
int | layerCount () const
bool | addLayer (const QString &name, QCPLayer *otherLayer=nullptr, LayerInsertMode insertMode=limAbove)
bool | removeLayer (QCPLayer *layer)
bool | moveLayer (QCPLayer *layer, QCPLayer *otherLayer, LayerInsertMode insertMode=limAbove)
int | axisRectCount () const
QCPAxisRect * | axisRect (int index=0) const
QList< QCPAxisRect * > | axisRects () const
QCPLayoutElement * | layoutElementAt (const QPointF &pos) const
QCPAxisRect * | axisRectAt (const QPointF &pos) const
Q_SLOT void | rescaleAxes (bool onlyVisiblePlottables=false)
QList< QCPAxis * > | selectedAxes () const
QList< QCPLegend * > | selectedLegends () const
Q_SLOT void | deselectAll ()
bool | savePdf (const QString &fileName, int width=0, int height=0, QCP::ExportPen exportPen=QCP::epAllowCosmetic, const QString &pdfCreator=QString(), const QString &pdfTitle=QString())
bool | savePng (const QString &fileName, int width=0, int height=0, double scale=1.0, int quality=-1, int resolution=96, QCP::ResolutionUnit resolutionUnit=QCP::ruDotsPerInch)
bool | saveJpg (const QString &fileName, int width=0, int height=0, double scale=1.0, int quality=-1, int resolution=96, QCP::ResolutionUnit resolutionUnit=QCP::ruDotsPerInch)
bool | saveBmp (const QString &fileName, int width=0, int height=0, double scale=1.0, int resolution=96, QCP::ResolutionUnit resolutionUnit=QCP::ruDotsPerInch)
bool | saveRastered (const QString &fileName, int width, int height, double scale, const char *format, int quality=-1, int resolution=96, QCP::ResolutionUnit resolutionUnit=QCP::ruDotsPerInch)
QPixmap | toPixmap (int width=0, int height=0, double scale=1.0)
void | toPainter (QCPPainter *painter, int width=0, int height=0)
Q_SLOT void | replot (QCustomPlot::RefreshPriority refreshPriority=QCustomPlot::rpRefreshHint)
double | replotTime (bool average=false) const

## Public Members
QCPAxis * | xAxis
QCPAxis * | yAxis
QCPAxis * | xAxis2
QCPAxis * | yAxis2
QCPLegend * | legend

## Signals
void | mouseDoubleClick (QMouseEvent *event)
void | mousePress (QMouseEvent *event)
void | mouseMove (QMouseEvent *event)
void | mouseRelease (QMouseEvent *event)
void | mouseWheel (QWheelEvent *event)
void | plottableClick (QCPAbstractPlottable *plottable, int dataIndex, QMouseEvent *event)
void | plottableDoubleClick (QCPAbstractPlottable *plottable, int dataIndex, QMouseEvent *event)
void | itemClick (QCPAbstractItem *item, QMouseEvent *event)
void | itemDoubleClick (QCPAbstractItem *item, QMouseEvent *event)
void | axisClick (QCPAxis *axis, QCPAxis::SelectablePart part, QMouseEvent *event)
void | axisDoubleClick (QCPAxis *axis, QCPAxis::SelectablePart part, QMouseEvent *event)
void | legendClick (QCPLegend *legend, QCPAbstractLegendItem *item, QMouseEvent *event)
void | legendDoubleClick (QCPLegend *legend, QCPAbstractLegendItem *item, QMouseEvent *event)
void | selectionChangedByUser ()
void | beforeReplot ()
void | afterLayout ()
void | afterReplot ()

## Protected Functions
virtual QSize | minimumSizeHint () const
virtual QSize | sizeHint () const
virtual void | paintEvent (QPaintEvent *event)
virtual void | resizeEvent (QResizeEvent *event)
virtual void | mouseDoubleClickEvent (QMouseEvent *event)
virtual void | mousePressEvent (QMouseEvent *event)
virtual void | mouseMoveEvent (QMouseEvent *event)
virtual void | mouseReleaseEvent (QMouseEvent *event)
virtual void | wheelEvent (QWheelEvent *event)
virtual void | draw (QCPPainter *painter)
virtual void | updateLayout ()
virtual void | axisRemoved (QCPAxis *axis)
virtual void | legendRemoved (QCPLegend *legend)
virtual Q_SLOT void | processRectSelection (QRect rect, QMouseEvent *event)
virtual Q_SLOT void | processRectZoom (QRect rect, QMouseEvent *event)
virtual Q_SLOT void | processPointSelection (QMouseEvent *event)
bool | registerPlottable (QCPAbstractPlottable *plottable)
bool | registerGraph (QCPGraph *graph)
bool | registerItem (QCPAbstractItem *item)
void | updateLayerIndices () const
QCPLayerable * | layerableAt (const QPointF &pos, bool onlySelectable, QVariant *selectionDetails=nullptr) const
QList< QCPLayerable * > | layerableListAt (const QPointF &pos, bool onlySelectable, QList< QVariant > *selectionDetails=nullptr) const
void | drawBackground (QCPPainter *painter)
void | setupPaintBuffers ()
QCPAbstractPaintBuffer * | createPaintBuffer ()
bool | hasInvalidatedPaintBuffers ()
bool | setupOpenGl ()
void | freeOpenGl ()

## Detailed Description

The central class of the library. This is the QWidget which displays the plot and interacts with the user.

For tutorials on how to use QCustomPlot, see the website
https://www.qcustomplot.com/

## Member Enumeration Documentation

## ◆ LayerInsertMode

enum QCustomPlot::LayerInsertMode

Defines how a layer should be inserted relative to an other layer.

See also
  addLayer, moveLayer

Enumerator
limBelow | Layer is inserted below other layer.
limAbove | Layer is inserted above other layer.

## ◆ RefreshPriority

enum QCustomPlot::RefreshPriority

Defines with what timing the QCustomPlot surface is refreshed after a replot.

See also
  replot

Enumerator
rpImmediateRefresh | Replots immediately and repaints the widget immediately by calling QWidget::repaint() after the replot.
rpQueuedRefresh | Replots immediately, but queues the widget repaint, by calling QWidget::update() after the replot. This way multiple redundant widget repaints can be avoided.
rpRefreshHint | Whether to use immediate or queued refresh depends on whether the plotting hint QCP::phImmediateRefresh is set, see setPlottingHints.
rpQueuedReplot | Queues the entire replot for the next event loop iteration. This way multiple redundant replots can be avoided. The actual replot is then done with rpRefreshHint priority.

## Constructor & Destructor Documentation

## ◆ QCustomPlot()

QCustomPlot::QCustomPlot | ( | QWidget * | parent = nullptr | ) |
| explicit

Constructs a QCustomPlot and sets reasonable default values.

## Member Function Documentation

## ◆ plotLayout()

QCPLayoutGrid * QCustomPlot::plotLayout | ( |  | ) | const
| inline

Returns the top level layout of this QCustomPlot instance. It is a QCPLayoutGrid, initially containing just one cell with the main QCPAxisRect inside.

## ◆ selectionRect()

QCPSelectionRect * QCustomPlot::selectionRect | ( |  | ) | const
| inline

Allows access to the currently used QCPSelectionRect instance (or subclass thereof), that is used to handle and draw selection rect interactions (see setSelectionRectMode).

See also
  setSelectionRect

## ◆ setViewport()

void QCustomPlot::setViewport | ( | const QRect & | rect | ) |

Sets the viewport of this QCustomPlot. Usually users of QCustomPlot don't need to change the viewport manually.

The viewport is the area in which the plot is drawn. All mechanisms, e.g. margin calculation take the viewport to be the outer border of the plot. The viewport normally is the rect() of the QCustomPlot widget, i.e. a rect with top left (0, 0) and size of the QCustomPlot widget.

Don't confuse the viewport with the axis rect (QCustomPlot::axisRect). An axis rect is typically an area enclosed by four axes, where the graphs/plottables are drawn in. The viewport is larger and contains also the axes themselves, their tick numbers, their labels, or even additional axis rects, color scales and other layout elements.

This function is used to allow arbitrary size exports with toPixmap, savePng, savePdf, etc. by temporarily changing the viewport size.

## ◆ setBufferDevicePixelRatio()

void QCustomPlot::setBufferDevicePixelRatio | ( | double | ratio | ) |

Sets the device pixel ratio used by the paint buffers of this QCustomPlot instance.

Normally, this doesn't need to be set manually, because it is initialized with the regular QWidget::devicePixelRatio which is configured by Qt to fit the display device (e.g. 1 for normal displays, 2 for High-DPI displays).

Device pixel ratios are supported by Qt only for Qt versions since 5.4. If this method is called when QCustomPlot is being used with older Qt versions, outputs an according qDebug message and leaves the internal buffer device pixel ratio at 1.0.

## ◆ setBackground() [1/3]

void QCustomPlot::setBackground | ( | const QPixmap & | pm | ) |

Sets pm as the viewport background pixmap (see setViewport). The pixmap is always drawn below all other objects in the plot.

For cases where the provided pixmap doesn't have the same size as the viewport, scaling can be enabled with setBackgroundScaled and the scaling mode (whether and how the aspect ratio is preserved) can be set with setBackgroundScaledMode. To set all these options in one call, consider using the overloaded version of this function.

If a background brush was set with setBackground(const QBrush &brush), the viewport will first be filled with that brush, before drawing the background pixmap. This can be useful for background pixmaps with translucent areas.

See also
  setBackgroundScaled, setBackgroundScaledMode

## ◆ setBackground() [2/3]

void QCustomPlot::setBackground | ( | const QPixmap & | pm,
|  | bool | scaled,
|  | Qt::AspectRatioMode | mode = Qt::KeepAspectRatioByExpanding )

This is an overloaded function.
Allows setting the background pixmap of the viewport, whether it shall be scaled and how it shall be scaled in one call.

See also
  setBackground(const QPixmap &pm), setBackgroundScaled, setBackgroundScaledMode

## ◆ setBackground() [3/3]

void QCustomPlot::setBackground | ( | const QBrush & | brush | ) |

Sets the background brush of the viewport (see setViewport).

Before drawing everything else, the background is filled with brush. If a background pixmap was set with setBackground(const QPixmap &pm), this brush will be used to fill the viewport before the background pixmap is drawn. This can be useful for background pixmaps with translucent areas.

Set brush to Qt::NoBrush or Qt::Transparent to leave background transparent. This can be useful for exporting to image formats which support transparency, e.g. savePng.

See also
  setBackgroundScaled, setBackgroundScaledMode

## ◆ setBackgroundScaled()

void QCustomPlot::setBackgroundScaled | ( | bool | scaled | ) |

Sets whether the viewport background pixmap shall be scaled to fit the viewport. If scaled is set to true, control whether and how the aspect ratio of the original pixmap is preserved with setBackgroundScaledMode.

Note that the scaled version of the original pixmap is buffered, so there is no performance penalty on replots. (Except when the viewport dimensions are changed continuously.)

See also
  setBackground, setBackgroundScaledMode

## ◆ setBackgroundScaledMode()

void QCustomPlot::setBackgroundScaledMode | ( | Qt::AspectRatioMode | mode | ) |

If scaling of the viewport background pixmap is enabled (setBackgroundScaled), use this function to define whether and how the aspect ratio of the original pixmap is preserved.

See also
  setBackground, setBackgroundScaled

## ◆ setAntialiasedElements()

void QCustomPlot::setAntialiasedElements | ( | const QCP::AntialiasedElements & | antialiasedElements | ) |

Sets which elements are forcibly drawn antialiased as an or combination of QCP::AntialiasedElement.

This overrides the antialiasing settings for whole element groups, normally controlled with the setAntialiasing function on the individual elements. If an element is neither specified in setAntialiasedElements nor in setNotAntialiasedElements, the antialiasing setting on each individual element instance is used.

For example, if antialiasedElements contains QCP::aePlottables, all plottables will be drawn antialiased, no matter what the specific QCPAbstractPlottable::setAntialiased value was set to.

if an element in antialiasedElements is already set in setNotAntialiasedElements, it is removed from there.

See also
  setNotAntialiasedElements

## ◆ setAntialiasedElement()

void QCustomPlot::setAntialiasedElement | ( | QCP::AntialiasedElement | antialiasedElement,
|  | bool | enabled = true )

Sets whether the specified antialiasedElement is forcibly drawn antialiased.

See setAntialiasedElements for details.

See also
  setNotAntialiasedElement

## ◆ setNotAntialiasedElements()

void QCustomPlot::setNotAntialiasedElements | ( | const QCP::AntialiasedElements & | notAntialiasedElements | ) |

Sets which elements are forcibly drawn not antialiased as an or combination of QCP::AntialiasedElement.

This overrides the antialiasing settings for whole element groups, normally controlled with the setAntialiasing function on the individual elements. If an element is neither specified in setAntialiasedElements nor in setNotAntialiasedElements, the antialiasing setting on each individual element instance is used.

For example, if notAntialiasedElements contains QCP::aePlottables, no plottables will be drawn antialiased, no matter what the specific QCPAbstractPlottable::setAntialiased value was set to.

if an element in notAntialiasedElements is already set in setAntialiasedElements, it is removed from there.

See also
  setAntialiasedElements

## ◆ setNotAntialiasedElement()

void QCustomPlot::setNotAntialiasedElement | ( | QCP::AntialiasedElement | notAntialiasedElement,
|  | bool | enabled = true )

Sets whether the specified notAntialiasedElement is forcibly drawn not antialiased.

See setNotAntialiasedElements for details.

See also
  setAntialiasedElement

## ◆ setAutoAddPlottableToLegend()

void QCustomPlot::setAutoAddPlottableToLegend | ( | bool | on | ) |

If set to true, adding a plottable (e.g. a graph) to the QCustomPlot automatically also adds the plottable to the legend (QCustomPlot::legend).

See also
  addGraph, QCPLegend::addItem

## ◆ setInteractions()

void QCustomPlot::setInteractions | ( | const QCP::Interactions & | interactions | ) |

Sets the possible interactions of this QCustomPlot as an or-combination of QCP::Interaction enums. There are the following types of interactions:

Axis range manipulation is controlled via QCP::iRangeDrag and QCP::iRangeZoom. When the respective interaction is enabled, the user may drag axes ranges and zoom with the mouse wheel. For details how to control which axes the user may drag/zoom and in what orientations, see QCPAxisRect::setRangeDrag, QCPAxisRect::setRangeZoom, QCPAxisRect::setRangeDragAxes, QCPAxisRect::setRangeZoomAxes.

Plottable data selection is controlled by QCP::iSelectPlottables. If QCP::iSelectPlottables is set, the user may select plottables (graphs, curves, bars,...) and their data by clicking on them or in their vicinity (setSelectionTolerance). Whether the user can actually select a plottable and its data can further be restricted with the QCPAbstractPlottable::setSelectable method on the specific plottable. For details, see the special page about the data selection mechanism. To retrieve a list of all currently selected plottables, call selectedPlottables. If you're only interested in QCPGraphs, you may use the convenience function selectedGraphs.

Item selection is controlled by QCP::iSelectItems. If QCP::iSelectItems is set, the user may select items (QCPItemLine, QCPItemText,...) by clicking on them or in their vicinity. To find out whether a specific item is selected, call QCPAbstractItem::selected(). To retrieve a list of all currently selected items, call selectedItems.

Axis selection is controlled with QCP::iSelectAxes. If QCP::iSelectAxes is set, the user may select parts of the axes by clicking on them. What parts exactly (e.g. Axis base line, tick labels, axis label) are selectable can be controlled via QCPAxis::setSelectableParts for each axis. To retrieve a list of all axes that currently contain selected parts, call selectedAxes. Which parts of an axis are selected, can be retrieved with QCPAxis::selectedParts().

Legend selection is controlled with QCP::iSelectLegend. If this is set, the user may select the legend itself or individual items by clicking on them. What parts exactly are selectable can be controlled via QCPLegend::setSelectableParts. To find out whether the legend or any of its child items are selected, check the value of QCPLegend::selectedParts. To find out which child items are selected, call QCPLegend::selectedItems.

All other selectable elements The selection of all other selectable objects (e.g. QCPTextElement, or your own layerable subclasses) is controlled with QCP::iSelectOther. If set, the user may select those objects by clicking on them. To find out which are currently selected, you need to check their selected state explicitly.

If the selection state has changed by user interaction, the selectionChangedByUser signal is emitted. Each selectable object additionally emits an individual selectionChanged signal whenever their selection state has changed, i.e. not only by user interaction.

To allow multiple objects to be selected by holding the selection modifier (setMultiSelectModifier), set the flag QCP::iMultiSelect.

Note
  In addition to the selection mechanism presented here, QCustomPlot always emits corresponding signals, when an object is clicked or double clicked. see plottableClick and plottableDoubleClick for example.

See also
  setInteraction, setSelectionTolerance

## ◆ setInteraction()

void QCustomPlot::setInteraction | ( | const QCP::Interaction & | interaction,
|  | bool | enabled = true )

Sets the single interaction of this QCustomPlot to enabled.

For details about the interaction system, see setInteractions.

See also
  setInteractions

## ◆ setSelectionTolerance()

void QCustomPlot::setSelectionTolerance | ( | int | pixels | ) |

Sets the tolerance that is used to decide whether a click selects an object (e.g. a plottable) or not.

If the user clicks in the vicinity of the line of e.g. a QCPGraph, it's only regarded as a potential selection when the minimum distance between the click position and the graph line is smaller than pixels. Objects that are defined by an area (e.g. QCPBars) only react to clicks directly inside the area and ignore this selection tolerance. In other words, it only has meaning for parts of objects that are too thin to exactly hit with a click and thus need such a tolerance.

See also
  setInteractions, QCPLayerable::selectTest

## ◆ setNoAntialiasingOnDrag()

void QCustomPlot::setNoAntialiasingOnDrag | ( | bool | enabled | ) |

Sets whether antialiasing is disabled for this QCustomPlot while the user is dragging axes ranges. If many objects, especially plottables, are drawn antialiased, this greatly improves performance during dragging. Thus it creates a more responsive user experience. As soon as the user stops dragging, the last replot is done with normal antialiasing, to restore high image quality.

See also
  setAntialiasedElements, setNotAntialiasedElements

## ◆ setPlottingHints()

void QCustomPlot::setPlottingHints | ( | const QCP::PlottingHints & | hints | ) |

Sets the plotting hints for this QCustomPlot instance as an or combination of QCP::PlottingHint.

See also
  setPlottingHint

## ◆ setPlottingHint()

void QCustomPlot::setPlottingHint | ( | QCP::PlottingHint | hint,
|  | bool | enabled = true )

Sets the specified plotting hint to enabled.

See also
  setPlottingHints

## ◆ setMultiSelectModifier()

void QCustomPlot::setMultiSelectModifier | ( | Qt::KeyboardModifier | modifier | ) |

Sets the keyboard modifier that will be recognized as multi-select-modifier.

If QCP::iMultiSelect is specified in setInteractions, the user may select multiple objects (or data points) by clicking on them one after the other while holding down modifier.

By default the multi-select-modifier is set to Qt::ControlModifier.

See also
  setInteractions

## ◆ setSelectionRectMode()

void QCustomPlot::setSelectionRectMode | ( | QCP::SelectionRectMode | mode | ) |

Sets how QCustomPlot processes mouse click-and-drag interactions by the user.

If mode is QCP::srmNone, the mouse drag is forwarded to the underlying objects. For example, QCPAxisRect may process a mouse drag by dragging axis ranges, see QCPAxisRect::setRangeDrag. If mode is not QCP::srmNone, the current selection rect (selectionRect) becomes activated and allows e.g. rect zooming and data point selection.

If you wish to provide your user both with axis range dragging and data selection/range zooming, use this method to switch between the modes just before the interaction is processed, e.g. in reaction to the mousePress or mouseMove signals. For example you could check whether the user is holding a certain keyboard modifier, and then decide which mode shall be set.

If a selection rect interaction is currently active, and mode is set to QCP::srmNone, the interaction is canceled (QCPSelectionRect::cancel). Switching between any of the other modes will keep the selection rect active. Upon completion of the interaction, the behaviour is as defined by the currently set mode, not the mode that was set when the interaction started.

See also
  setInteractions, setSelectionRect, QCPSelectionRect

## ◆ setSelectionRect()

void QCustomPlot::setSelectionRect | ( | QCPSelectionRect * | selectionRect | ) |

Sets the QCPSelectionRect instance that QCustomPlot will use if mode is not QCP::srmNone and the user performs a click-and-drag interaction. QCustomPlot takes ownership of the passed selectionRect. It can be accessed later via selectionRect.

This method is useful if you wish to replace the default QCPSelectionRect instance with an instance of a QCPSelectionRect subclass, to introduce custom behaviour of the selection rect.

See also
  setSelectionRectMode

## ◆ setOpenGl()

void QCustomPlot::setOpenGl | ( | bool | enabled,
|  | int | multisampling = 16 )

Warning
  This is still an experimental feature and its performance depends on the system that it runs on. Having multiple QCustomPlot widgets in one application with enabled OpenGL rendering might cause context conflicts on some systems.

This method allows to enable OpenGL plot rendering, for increased plotting performance of graphically demanding plots (thick lines, translucent fills, etc.).

If enabled is set to true, QCustomPlot will try to initialize OpenGL and, if successful, continue plotting with hardware acceleration. The parameter multisampling controls how many samples will be used per pixel, it essentially controls the antialiasing quality. If multisampling is set too high for the current graphics hardware, the maximum allowed value will be used.

You can test whether switching to OpenGL rendering was successful by checking whether the according getter QCustomPlot::openGl() returns true. If the OpenGL initialization fails, rendering continues with the regular software rasterizer, and an according qDebug output is generated.

If switching to OpenGL was successful, this method disables label caching (setPlottingHint(QCP::phCacheLabels, false)) and turns on QCustomPlot's antialiasing override for all elements (setAntialiasedElements(QCP::aeAll)), leading to a higher quality output. The antialiasing override allows for pixel-grid aligned drawing in the OpenGL paint device. As stated before, in OpenGL rendering the actual antialiasing of the plot is controlled with multisampling. If enabled is set to false, the antialiasing/label caching settings are restored to what they were before OpenGL was enabled, if they weren't altered in the meantime.

Note
  OpenGL support is only enabled if QCustomPlot is compiled with the macro `QCUSTOMPLOT_USE_OPENGL` defined. This define must be set before including the QCustomPlot header both during compilation of the QCustomPlot library as well as when compiling your application. It is best to just include the line DEFINES += QCUSTOMPLOT_USE_OPENGL in the respective qmake project files.
  If you are using a Qt version before 5.0, you must also add the module "opengl" to your `QT` variable in the qmake project files. For Qt versions 5.0 and higher, QCustomPlot switches to a newer OpenGL interface which is already in the "gui" module.

## ◆ plottable() [1/2]

QCPAbstractPlottable * QCustomPlot::plottable | ( | int | index | ) |

Returns the plottable with index. If the index is invalid, returns `nullptr`.

There is an overloaded version of this function with no parameter which returns the last added plottable, see QCustomPlot::plottable()

See also
  plottableCount

## ◆ plottable() [2/2]

QCPAbstractPlottable * QCustomPlot::plottable | ( |  | ) |

This is an overloaded function.
Returns the last plottable that was added to the plot. If there are no plottables in the plot, returns `nullptr`.

See also
  plottableCount

## ◆ removePlottable() [1/2]

bool QCustomPlot::removePlottable | ( | QCPAbstractPlottable * | plottable | ) |

Removes the specified plottable from the plot and deletes it. If necessary, the corresponding legend item is also removed from the default legend (QCustomPlot::legend).

Returns true on success.

See also
  clearPlottables

## ◆ removePlottable() [2/2]

bool QCustomPlot::removePlottable | ( | int | index | ) |

This is an overloaded function.
Removes and deletes the plottable by its index.

## ◆ clearPlottables()

int QCustomPlot::clearPlottables | ( |  | ) |

Removes all plottables from the plot and deletes them. Corresponding legend items are also removed from the default legend (QCustomPlot::legend).

Returns the number of plottables removed.

See also
  removePlottable

## ◆ plottableCount()

int QCustomPlot::plottableCount | ( |  | ) | const

Returns the number of currently existing plottables in the plot

See also
  plottable

## ◆ selectedPlottables()

QList< QCPAbstractPlottable * > QCustomPlot::selectedPlottables | ( |  | ) | const

Returns a list of the selected plottables. If no plottables are currently selected, the list is empty.

There is a convenience function if you're only interested in selected graphs, see selectedGraphs.

See also
  setInteractions, QCPAbstractPlottable::setSelectable, QCPAbstractPlottable::setSelection

## ◆ plottableAt() [1/2]

template<class PlottableType>

PlottableType * QCustomPlot::plottableAt | ( | const QPointF & | pos,
|  | bool | onlySelectable = false,
|  | int * | dataIndex = nullptr ) const

Returns the plottable at the pixel position pos. The plottable type (a QCPAbstractPlottable subclass) that shall be taken into consideration can be specified via the template parameter.

Plottables that only consist of single lines (like graphs) have a tolerance band around them, see setSelectionTolerance. If multiple plottables come into consideration, the one closest to pos is returned.

If onlySelectable is true, only plottables that are selectable (QCPAbstractPlottable::setSelectable) are considered.

if dataIndex is non-null, it is set to the index of the plottable's data point that is closest to pos.

If there is no plottable of the specified type at pos, returns `nullptr`.

See also
  itemAt, layoutElementAt

## ◆ plottableAt() [2/2]

QCPAbstractPlottable * QCustomPlot::plottableAt | ( | const QPointF & | pos,
|  | bool | onlySelectable = false,
|  | int * | dataIndex = nullptr ) const

Returns any plottable at the pixel position pos. Since it can capture all plottables, the return type is the abstract base class of all plottables, QCPAbstractPlottable.

For details, and if you wish to specify a certain plottable type (e.g. QCPGraph), see the template method plottableAt<PlottableType>()

See also
  plottableAt<PlottableType>(), itemAt, layoutElementAt

## ◆ hasPlottable()

bool QCustomPlot::hasPlottable | ( | QCPAbstractPlottable * | plottable | ) | const

Returns whether this QCustomPlot instance contains the plottable.

## ◆ graph() [1/2]

QCPGraph * QCustomPlot::graph | ( | int | index | ) | const

Returns the graph with index. If the index is invalid, returns `nullptr`.

There is an overloaded version of this function with no parameter which returns the last created graph, see QCustomPlot::graph()

See also
  graphCount, addGraph

## ◆ graph() [2/2]

QCPGraph * QCustomPlot::graph | ( |  | ) | const

This is an overloaded function.
Returns the last graph, that was created with addGraph. If there are no graphs in the plot, returns `nullptr`.

See also
  graphCount, addGraph

## ◆ addGraph()

QCPGraph * QCustomPlot::addGraph | ( | QCPAxis * | keyAxis = nullptr,
|  | QCPAxis * | valueAxis = nullptr )

Creates a new graph inside the plot. If keyAxis and valueAxis are left unspecified (0), the bottom (xAxis) is used as key and the left (yAxis) is used as value axis. If specified, keyAxis and valueAxis must reside in this QCustomPlot.

keyAxis will be used as key axis (typically "x") and valueAxis as value axis (typically "y") for the graph.

Returns a pointer to the newly created graph, or `nullptr` if adding the graph failed.

See also
  graph, graphCount, removeGraph, clearGraphs

## ◆ removeGraph() [1/2]

bool QCustomPlot::removeGraph | ( | QCPGraph * | graph | ) |

Removes the specified graph from the plot and deletes it. If necessary, the corresponding legend item is also removed from the default legend (QCustomPlot::legend). If any other graphs in the plot have a channel fill set towards the removed graph, the channel fill property of those graphs is reset to `nullptr` (no channel fill).

Returns true on success.

See also
  clearGraphs

## ◆ removeGraph() [2/2]

bool QCustomPlot::removeGraph | ( | int | index | ) |

This is an overloaded function.
Removes and deletes the graph by its index.

## ◆ clearGraphs()

int QCustomPlot::clearGraphs | ( |  | ) |

Removes all graphs from the plot and deletes them. Corresponding legend items are also removed from the default legend (QCustomPlot::legend).

Returns the number of graphs removed.

See also
  removeGraph

## ◆ graphCount()

int QCustomPlot::graphCount | ( |  | ) | const

Returns the number of currently existing graphs in the plot

See also
  graph, addGraph

## ◆ selectedGraphs()

QList< QCPGraph * > QCustomPlot::selectedGraphs | ( |  | ) | const

Returns a list of the selected graphs. If no graphs are currently selected, the list is empty.

If you are not only interested in selected graphs but other plottables like QCPCurve, QCPBars, etc., use selectedPlottables.

See also
  setInteractions, selectedPlottables, QCPAbstractPlottable::setSelectable, QCPAbstractPlottable::setSelection

## ◆ item() [1/2]

QCPAbstractItem * QCustomPlot::item | ( | int | index | ) | const

Returns the item with index. If the index is invalid, returns `nullptr`.

There is an overloaded version of this function with no parameter which returns the last added item, see QCustomPlot::item()

See also
  itemCount

## ◆ item() [2/2]

QCPAbstractItem * QCustomPlot::item | ( |  | ) | const

This is an overloaded function.
Returns the last item that was added to this plot. If there are no items in the plot, returns `nullptr`.

See also
  itemCount

## ◆ removeItem() [1/2]

bool QCustomPlot::removeItem | ( | QCPAbstractItem * | item | ) |

Removes the specified item from the plot and deletes it.

Returns true on success.

See also
  clearItems

## ◆ removeItem() [2/2]

bool QCustomPlot::removeItem | ( | int | index | ) |

This is an overloaded function.
Removes and deletes the item by its index.

## ◆ clearItems()

int QCustomPlot::clearItems | ( |  | ) |

Removes all items from the plot and deletes them.

Returns the number of items removed.

See also
  removeItem

## ◆ itemCount()

int QCustomPlot::itemCount | ( |  | ) | const

Returns the number of currently existing items in the plot

See also
  item

## ◆ selectedItems()

QList< QCPAbstractItem * > QCustomPlot::selectedItems | ( |  | ) | const

Returns a list of the selected items. If no items are currently selected, the list is empty.

See also
  setInteractions, QCPAbstractItem::setSelectable, QCPAbstractItem::setSelected

## ◆ itemAt() [1/2]

template<class ItemType>

ItemType * QCustomPlot::itemAt | ( | const QPointF & | pos,
|  | bool | onlySelectable = false ) const

Returns the item at the pixel position pos. The item type (a QCPAbstractItem subclass) that shall be taken into consideration can be specified via the template parameter. Items that only consist of single lines (e.g. QCPItemLine or QCPItemCurve) have a tolerance band around them, see setSelectionTolerance. If multiple items come into consideration, the one closest to pos is returned.

If onlySelectable is true, only items that are selectable (QCPAbstractItem::setSelectable) are considered.

If there is no item at pos, returns `nullptr`.

See also
  plottableAt, layoutElementAt

## ◆ itemAt() [2/2]

QCPAbstractItem * QCustomPlot::itemAt | ( | const QPointF & | pos,
|  | bool | onlySelectable = false ) const

Returns the item at the pixel position pos. Since it can capture all items, the return type is the abstract base class of all items, QCPAbstractItem.

For details, and if you wish to specify a certain item type (e.g. QCPItemLine), see the template method itemAt<ItemType>()

See also
  itemAt<ItemType>(), plottableAt, layoutElementAt

## ◆ hasItem()

bool QCustomPlot::hasItem | ( | QCPAbstractItem * | item | ) | const

Returns whether this QCustomPlot contains the item.

See also
  item

## ◆ layer() [1/2]

QCPLayer * QCustomPlot::layer | ( | const QString & | name | ) | const

Returns the layer with the specified name. If there is no layer with the specified name, `nullptr` is returned.

Layer names are case-sensitive.

See also
  addLayer, moveLayer, removeLayer

## ◆ layer() [2/2]

QCPLayer * QCustomPlot::layer | ( | int | index | ) | const

This is an overloaded function.
Returns the layer by index. If the index is invalid, `nullptr` is returned.

See also
  addLayer, moveLayer, removeLayer

## ◆ currentLayer()

QCPLayer * QCustomPlot::currentLayer | ( |  | ) | const

Returns the layer that is set as current layer (see setCurrentLayer).

## ◆ setCurrentLayer() [1/2]

bool QCustomPlot::setCurrentLayer | ( | const QString & | name | ) |

Sets the layer with the specified name to be the current layer. All layerables (QCPLayerable), e.g. plottables and items, are created on the current layer.

Returns true on success, i.e. if there is a layer with the specified name in the QCustomPlot.

Layer names are case-sensitive.

See also
  addLayer, moveLayer, removeLayer, QCPLayerable::setLayer

## ◆ setCurrentLayer() [2/2]

bool QCustomPlot::setCurrentLayer | ( | QCPLayer * | layer | ) |

This is an overloaded function.
Sets the provided layer to be the current layer.

Returns true on success, i.e. when layer is a valid layer in the QCustomPlot.

See also
  addLayer, moveLayer, removeLayer

## ◆ layerCount()

int QCustomPlot::layerCount | ( |  | ) | const

Returns the number of currently existing layers in the plot

See also
  layer, addLayer

## ◆ addLayer()

bool QCustomPlot::addLayer | ( | const QString & | name,
|  | QCPLayer * | otherLayer = nullptr,
|  | QCustomPlot::LayerInsertMode | insertMode = limAbove )

Adds a new layer to this QCustomPlot instance. The new layer will have the name name, which must be unique. Depending on insertMode, it is positioned either below or above otherLayer.

Returns true on success, i.e. if there is no other layer named name and otherLayer is a valid layer inside this QCustomPlot.

If otherLayer is 0, the highest layer in the QCustomPlot will be used.

For an explanation of what layers are in QCustomPlot, see the documentation of QCPLayer.

See also
  layer, moveLayer, removeLayer

## ◆ removeLayer()

bool QCustomPlot::removeLayer | ( | QCPLayer * | layer | ) |

Removes the specified layer and returns true on success.

All layerables (e.g. plottables and items) on the removed layer will be moved to the layer below layer. If layer is the bottom layer, the layerables are moved to the layer above. In both cases, the total rendering order of all layerables in the QCustomPlot is preserved.

If layer is the current layer (setCurrentLayer), the layer below (or above, if bottom layer) becomes the new current layer.

It is not possible to remove the last layer of the plot.

See also
  layer, addLayer, moveLayer

## ◆ moveLayer()

bool QCustomPlot::moveLayer | ( | QCPLayer * | layer,
|  | QCPLayer * | otherLayer,
|  | QCustomPlot::LayerInsertMode | insertMode = limAbove )

Moves the specified layer either above or below otherLayer. Whether it's placed above or below is controlled with insertMode.

Returns true on success, i.e. when both layer and otherLayer are valid layers in the QCustomPlot.

See also
  layer, addLayer, moveLayer

## ◆ axisRectCount()

int QCustomPlot::axisRectCount | ( |  | ) | const

Returns the number of axis rects in the plot.

All axis rects can be accessed via QCustomPlot::axisRect().

Initially, only one axis rect exists in the plot.

See also
  axisRect, axisRects

## ◆ axisRect()

QCPAxisRect * QCustomPlot::axisRect | ( | int | index = 0 | ) | const

Returns the axis rect with index.

Initially, only one axis rect (with index 0) exists in the plot. If multiple axis rects were added, all of them may be accessed with this function in a linear fashion (even when they are nested in a layout hierarchy or inside other axis rects via QCPAxisRect::insetLayout).

The order of the axis rects is given by the fill order of the QCPLayout that is holding them. For example, if the axis rects are in the top level grid layout (accessible via QCustomPlot::plotLayout), they are ordered from left to right, top to bottom, if the layout's default setFillOrder of foColumnsFirst wasn't changed.

If you want to access axis rects by their row and column index, use the layout interface. For example, use QCPLayoutGrid::element of the top level grid layout, and `qobject_cast` the returned layout element to QCPAxisRect. (See also The Layout System.)

See also
  axisRectCount, axisRects, QCPLayoutGrid::setFillOrder

## ◆ axisRects()

QList< QCPAxisRect * > QCustomPlot::axisRects | ( |  | ) | const

Returns all axis rects in the plot.

The order of the axis rects is given by the fill order of the QCPLayout that is holding them. For example, if the axis rects are in the top level grid layout (accessible via QCustomPlot::plotLayout), they are ordered from left to right, top to bottom, if the layout's default setFillOrder of foColumnsFirst wasn't changed.

See also
  axisRectCount, axisRect, QCPLayoutGrid::setFillOrder

## ◆ layoutElementAt()

QCPLayoutElement * QCustomPlot::layoutElementAt | ( | const QPointF & | pos | ) | const

Returns the layout element at pixel position pos. If there is no element at that position, returns `nullptr`.

Only visible elements are used. If QCPLayoutElement::setVisible on the element itself or on any of its parent elements is set to false, it will not be considered.

See also
  itemAt, plottableAt

## ◆ axisRectAt()

QCPAxisRect * QCustomPlot::axisRectAt | ( | const QPointF & | pos | ) | const

Returns the layout element of type QCPAxisRect at pixel position pos. This method ignores other layout elements even if they are visually in front of the axis rect (e.g. a QCPLegend). If there is no axis rect at that position, returns `nullptr`.

Only visible axis rects are used. If QCPLayoutElement::setVisible on the axis rect itself or on any of its parent elements is set to false, it will not be considered.

See also
  layoutElementAt

## ◆ rescaleAxes()

void QCustomPlot::rescaleAxes | ( | bool | onlyVisiblePlottables = false | ) |

Rescales the axes such that all plottables (like graphs) in the plot are fully visible.

if onlyVisiblePlottables is set to true, only the plottables that have their visibility set to true (QCPLayerable::setVisible), will be used to rescale the axes.

See also
  QCPAbstractPlottable::rescaleAxes, QCPAxis::rescale

## ◆ selectedAxes()

QList< QCPAxis * > QCustomPlot::selectedAxes | ( |  | ) | const

Returns the axes that currently have selected parts, i.e. whose selection state is not QCPAxis::spNone.

See also
  selectedPlottables, selectedLegends, setInteractions, QCPAxis::setSelectedParts, QCPAxis::setSelectableParts

## ◆ selectedLegends()

QList< QCPLegend * > QCustomPlot::selectedLegends | ( |  | ) | const

Returns the legends that currently have selected parts, i.e. whose selection state is not QCPLegend::spNone.

See also
  selectedPlottables, selectedAxes, setInteractions, QCPLegend::setSelectedParts, QCPLegend::setSelectableParts, QCPLegend::selectedItems

## ◆ deselectAll()

void QCustomPlot::deselectAll | ( |  | ) |

Deselects all layerables (plottables, items, axes, legends,...) of the QCustomPlot.

Since calling this function is not a user interaction, this does not emit the selectionChangedByUser signal. The individual selectionChanged signals are emitted though, if the objects were previously selected.

See also
  setInteractions, selectedPlottables, selectedItems, selectedAxes, selectedLegends

## ◆ savePdf()

bool QCustomPlot::savePdf | ( | const QString & | fileName,
|  | int | width = 0,
|  | int | height = 0,
|  | QCP::ExportPen | exportPen = QCP::epAllowCosmetic,
|  | const QString & | pdfCreator = QString(),
|  | const QString & | pdfTitle = QString() )

Saves a PDF with the vectorized plot to the file fileName. The axis ratio as well as the scale of texts and lines will be derived from the specified width and height. This means, the output will look like the normal on-screen output of a QCustomPlot widget with the corresponding pixel width and height. If either width or height is zero, the exported image will have the same dimensions as the QCustomPlot widget currently has.

Setting exportPen to QCP::epNoCosmetic allows to disable the use of cosmetic pens when drawing to the PDF file. Cosmetic pens are pens with numerical width 0, which are always drawn as a one pixel wide line, no matter what zoom factor is set in the PDF-Viewer. For more information about cosmetic pens, see the QPainter and QPen documentation.

The objects of the plot will appear in the current selection state. If you don't want any selected objects to be painted in their selected look, deselect everything with deselectAll before calling this function.

Returns true on success.

Warning
  - If you plan on editing the exported PDF file with a vector graphics editor like Inkscape, it is advised to set exportPen to QCP::epNoCosmetic to avoid losing those cosmetic lines (which might be quite many, because cosmetic pens are the default for e.g. axes and tick marks).
  - If calling this function inside the constructor of the parent of the QCustomPlot widget (i.e. the MainWindow constructor, if QCustomPlot is inside the MainWindow), always provide explicit non-zero widths and heights. If you leave width or height as 0 (default), this function uses the current width and height of the QCustomPlot widget. However, in Qt, these aren't defined yet inside the constructor, so you would get an image that has strange widths/heights.
  pdfCreator and pdfTitle may be used to set the according metadata fields in the resulting PDF file.

Note
  On Android systems, this method does nothing and issues an according qDebug warning message. This is also the case if for other reasons the define flag `QT_NO_PRINTER` is set.

See also
  savePng, saveBmp, saveJpg, saveRastered

## ◆ savePng()

bool QCustomPlot::savePng | ( | const QString & | fileName,
|  | int | width = 0,
|  | int | height = 0,
|  | double | scale = 1.0,
|  | int | quality = -1,
|  | int | resolution = 96,
|  | QCP::ResolutionUnit | resolutionUnit = QCP::ruDotsPerInch )

Saves a PNG image file to fileName on disc. The output plot will have the dimensions width and height in pixels, multiplied by scale. If either width or height is zero, the current width and height of the QCustomPlot widget is used instead. Line widths and texts etc. are not scaled up when larger widths/heights are used. If you want that effect, use the scale parameter.

For example, if you set both width and height to 100 and scale to 2, you will end up with an image file of size 200*200 in which all graphical elements are scaled up by factor 2 (line widths, texts, etc.). This scaling is not done by stretching a 100*100 image, the result will have full 200*200 pixel resolution.

If you use a high scaling factor, it is recommended to enable antialiasing for all elements by temporarily setting QCustomPlot::setAntialiasedElements to QCP::aeAll as this allows QCustomPlot to place objects with sub-pixel accuracy.

image compression can be controlled with the quality parameter which must be between 0 and 100 or -1 to use the default setting.

The resolution will be written to the image file header and has no direct consequence for the quality or the pixel size. However, if opening the image with a tool which respects the metadata, it will be able to scale the image to match either a given size in real units of length (inch, centimeters, etc.), or the target display DPI. You can specify in which units resolution is given, by setting resolutionUnit. The resolution is converted to the format's expected resolution unit internally.

Returns true on success. If this function fails, most likely the PNG format isn't supported by the system, see Qt docs about QImageWriter::supportedImageFormats().

The objects of the plot will appear in the current selection state. If you don't want any selected objects to be painted in their selected look, deselect everything with deselectAll before calling this function.

If you want the PNG to have a transparent background, call setBackground(const QBrush &brush) with no brush (Qt::NoBrush) or a transparent color (Qt::transparent), before saving.

Warning
  If calling this function inside the constructor of the parent of the QCustomPlot widget (i.e. the MainWindow constructor, if QCustomPlot is inside the MainWindow), always provide explicit non-zero widths and heights. If you leave width or height as 0 (default), this function uses the current width and height of the QCustomPlot widget. However, in Qt, these aren't defined yet inside the constructor, so you would get an image that has strange widths/heights.

See also
  savePdf, saveBmp, saveJpg, saveRastered

## ◆ saveJpg()

bool QCustomPlot::saveJpg | ( | const QString & | fileName,
|  | int | width = 0,
|  | int | height = 0,
|  | double | scale = 1.0,
|  | int | quality = -1,
|  | int | resolution = 96,
|  | QCP::ResolutionUnit | resolutionUnit = QCP::ruDotsPerInch )

Saves a JPEG image file to fileName on disc. The output plot will have the dimensions width and height in pixels, multiplied by scale. If either width or height is zero, the current width and height of the QCustomPlot widget is used instead. Line widths and texts etc. are not scaled up when larger widths/heights are used. If you want that effect, use the scale parameter.

For example, if you set both width and height to 100 and scale to 2, you will end up with an image file of size 200*200 in which all graphical elements are scaled up by factor 2 (line widths, texts, etc.). This scaling is not done by stretching a 100*100 image, the result will have full 200*200 pixel resolution.

If you use a high scaling factor, it is recommended to enable antialiasing for all elements by temporarily setting QCustomPlot::setAntialiasedElements to QCP::aeAll as this allows QCustomPlot to place objects with sub-pixel accuracy.

image compression can be controlled with the quality parameter which must be between 0 and 100 or -1 to use the default setting.

The resolution will be written to the image file header and has no direct consequence for the quality or the pixel size. However, if opening the image with a tool which respects the metadata, it will be able to scale the image to match either a given size in real units of length (inch, centimeters, etc.), or the target display DPI. You can specify in which units resolution is given, by setting resolutionUnit. The resolution is converted to the format's expected resolution unit internally.

Returns true on success. If this function fails, most likely the JPEG format isn't supported by the system, see Qt docs about QImageWriter::supportedImageFormats().

The objects of the plot will appear in the current selection state. If you don't want any selected objects to be painted in their selected look, deselect everything with deselectAll before calling this function.

Warning
  If calling this function inside the constructor of the parent of the QCustomPlot widget (i.e. the MainWindow constructor, if QCustomPlot is inside the MainWindow), always provide explicit non-zero widths and heights. If you leave width or height as 0 (default), this function uses the current width and height of the QCustomPlot widget. However, in Qt, these aren't defined yet inside the constructor, so you would get an image that has strange widths/heights.

See also
  savePdf, savePng, saveBmp, saveRastered

## ◆ saveBmp()

bool QCustomPlot::saveBmp | ( | const QString & | fileName,
|  | int | width = 0,
|  | int | height = 0,
|  | double | scale = 1.0,
|  | int | resolution = 96,
|  | QCP::ResolutionUnit | resolutionUnit = QCP::ruDotsPerInch )

Saves a BMP image file to fileName on disc. The output plot will have the dimensions width and height in pixels, multiplied by scale. If either width or height is zero, the current width and height of the QCustomPlot widget is used instead. Line widths and texts etc. are not scaled up when larger widths/heights are used. If you want that effect, use the scale parameter.

For example, if you set both width and height to 100 and scale to 2, you will end up with an image file of size 200*200 in which all graphical elements are scaled up by factor 2 (line widths, texts, etc.). This scaling is not done by stretching a 100*100 image, the result will have full 200*200 pixel resolution.

If you use a high scaling factor, it is recommended to enable antialiasing for all elements by temporarily setting QCustomPlot::setAntialiasedElements to QCP::aeAll as this allows QCustomPlot to place objects with sub-pixel accuracy.

The resolution will be written to the image file header and has no direct consequence for the quality or the pixel size. However, if opening the image with a tool which respects the metadata, it will be able to scale the image to match either a given size in real units of length (inch, centimeters, etc.), or the target display DPI. You can specify in which units resolution is given, by setting resolutionUnit. The resolution is converted to the format's expected resolution unit internally.

Returns true on success. If this function fails, most likely the BMP format isn't supported by the system, see Qt docs about QImageWriter::supportedImageFormats().

The objects of the plot will appear in the current selection state. If you don't want any selected objects to be painted in their selected look, deselect everything with deselectAll before calling this function.

Warning
  If calling this function inside the constructor of the parent of the QCustomPlot widget (i.e. the MainWindow constructor, if QCustomPlot is inside the MainWindow), always provide explicit non-zero widths and heights. If you leave width or height as 0 (default), this function uses the current width and height of the QCustomPlot widget. However, in Qt, these aren't defined yet inside the constructor, so you would get an image that has strange widths/heights.

See also
  savePdf, savePng, saveJpg, saveRastered

## ◆ saveRastered()

bool QCustomPlot::saveRastered | ( | const QString & | fileName,
|  | int | width,
|  | int | height,
|  | double | scale,
|  | const char * | format,
|  | int | quality = -1,
|  | int | resolution = 96,
|  | QCP::ResolutionUnit | resolutionUnit = QCP::ruDotsPerInch )

Saves the plot to a rastered image file fileName in the image format format. The plot is sized to width and height in pixels and scaled with scale. (width 100 and scale 2.0 lead to a full resolution file with width 200.) If the format supports compression, quality may be between 0 and 100 to control it.

Returns true on success. If this function fails, most likely the given format isn't supported by the system, see Qt docs about QImageWriter::supportedImageFormats().

The resolution will be written to the image file header (if the file format supports this) and has no direct consequence for the quality or the pixel size. However, if opening the image with a tool which respects the metadata, it will be able to scale the image to match either a given size in real units of length (inch, centimeters, etc.), or the target display DPI. You can specify in which units resolution is given, by setting resolutionUnit. The resolution is converted to the format's expected resolution unit internally.

See also
  saveBmp, saveJpg, savePng, savePdf

## ◆ toPixmap()

QPixmap QCustomPlot::toPixmap | ( | int | width = 0,
|  | int | height = 0,
|  | double | scale = 1.0 )

Renders the plot to a pixmap and returns it.

The plot is sized to width and height in pixels and scaled with scale. (width 100 and scale 2.0 lead to a full resolution pixmap with width 200.)

See also
  toPainter, saveRastered, saveBmp, savePng, saveJpg, savePdf

## ◆ toPainter()

void QCustomPlot::toPainter | ( | QCPPainter * | painter,
|  | int | width = 0,
|  | int | height = 0 )

Renders the plot using the passed painter.

The plot is sized to width and height in pixels. If the painter's scale is not 1.0, the resulting plot will appear scaled accordingly.

Note
  If you are restricted to using a QPainter (instead of QCPPainter), create a temporary QPicture and open a QCPPainter on it. Then call toPainter with this QCPPainter. After ending the paint operation on the picture, draw it with the QPainter. This will reproduce the painter actions the QCPPainter took, with a QPainter.

See also
  toPixmap

## ◆ replot()

void QCustomPlot::replot | ( | QCustomPlot::RefreshPriority | refreshPriority = QCustomPlot::rpRefreshHint | ) |

Causes a complete replot into the internal paint buffer(s). Finally, the widget surface is refreshed with the new buffer contents. This is the method that must be called to make changes to the plot, e.g. on the axis ranges or data points of graphs, visible.

The parameter refreshPriority can be used to fine-tune the timing of the replot. For example if your application calls replot very quickly in succession (e.g. multiple independent functions change some aspects of the plot and each wants to make sure the change gets replotted), it is advisable to set refreshPriority to QCustomPlot::rpQueuedReplot. This way, the actual replotting is deferred to the next event loop iteration. Multiple successive calls of replot with this priority will only cause a single replot, avoiding redundant replots and improving performance.

Under a few circumstances, QCustomPlot causes a replot by itself. Those are resize events of the QCustomPlot widget and user interactions (object selection and range dragging/zooming).

Before the replot happens, the signal beforeReplot is emitted. After the replot, afterReplot is emitted. It is safe to mutually connect the replot slot with any of those two signals on two QCustomPlots to make them replot synchronously, it won't cause an infinite recursion.

If a layer is in mode QCPLayer::lmBuffered (QCPLayer::setMode), it is also possible to replot only that specific layer via QCPLayer::replot. See the documentation there for details.

See also
  replotTime

## ◆ replotTime()

double QCustomPlot::replotTime | ( | bool | average = false | ) | const

Returns the time in milliseconds that the last replot took. If average is set to true, an exponential moving average over the last couple of replots is returned.

See also
  replot

## ◆ mouseDoubleClick

void QCustomPlot::mouseDoubleClick | ( | QMouseEvent * | event | ) |
| signal

This signal is emitted when the QCustomPlot receives a mouse double click event.

## ◆ mousePress

void QCustomPlot::mousePress | ( | QMouseEvent * | event | ) |
| signal

This signal is emitted when the QCustomPlot receives a mouse press event.

It is emitted before QCustomPlot handles any other mechanism like range dragging. So a slot connected to this signal can still influence the behaviour e.g. with QCPAxisRect::setRangeDrag or QCPAxisRect::setRangeDragAxes.

## ◆ mouseMove

void QCustomPlot::mouseMove | ( | QMouseEvent * | event | ) |
| signal

This signal is emitted when the QCustomPlot receives a mouse move event.

It is emitted before QCustomPlot handles any other mechanism like range dragging. So a slot connected to this signal can still influence the behaviour e.g. with QCPAxisRect::setRangeDrag or QCPAxisRect::setRangeDragAxes.

Warning
  It is discouraged to change the drag-axes with QCPAxisRect::setRangeDragAxes here, because the dragging starting point was saved the moment the mouse was pressed. Thus it only has a meaning for the range drag axes that were set at that moment. If you want to change the drag axes, consider doing this in the mousePress signal instead.

## ◆ mouseRelease

void QCustomPlot::mouseRelease | ( | QMouseEvent * | event | ) |
| signal

This signal is emitted when the QCustomPlot receives a mouse release event.

It is emitted before QCustomPlot handles any other mechanisms like object selection. So a slot connected to this signal can still influence the behaviour e.g. with setInteractions or QCPAbstractPlottable::setSelectable.

## ◆ mouseWheel

void QCustomPlot::mouseWheel | ( | QWheelEvent * | event | ) |
| signal

This signal is emitted when the QCustomPlot receives a mouse wheel event.

It is emitted before QCustomPlot handles any other mechanisms like range zooming. So a slot connected to this signal can still influence the behaviour e.g. with QCPAxisRect::setRangeZoom, QCPAxisRect::setRangeZoomAxes or QCPAxisRect::setRangeZoomFactor.

## ◆ plottableClick

void QCustomPlot::plottableClick | ( | QCPAbstractPlottable * | plottable,
|  | int | dataIndex,
|  | QMouseEvent * | event )
| signal

This signal is emitted when a plottable is clicked.

event is the mouse event that caused the click and plottable is the plottable that received the click. The parameter dataIndex indicates the data point that was closest to the click position.

See also
  plottableDoubleClick

## ◆ plottableDoubleClick

void QCustomPlot::plottableDoubleClick | ( | QCPAbstractPlottable * | plottable,
|  | int | dataIndex,
|  | QMouseEvent * | event )
| signal

This signal is emitted when a plottable is double clicked.

event is the mouse event that caused the click and plottable is the plottable that received the click. The parameter dataIndex indicates the data point that was closest to the click position.

See also
  plottableClick

## ◆ itemClick

void QCustomPlot::itemClick | ( | QCPAbstractItem * | item,
|  | QMouseEvent * | event )
| signal

This signal is emitted when an item is clicked.

event is the mouse event that caused the click and item is the item that received the click.

See also
  itemDoubleClick

## ◆ itemDoubleClick

void QCustomPlot::itemDoubleClick | ( | QCPAbstractItem * | item,
|  | QMouseEvent * | event )
| signal

This signal is emitted when an item is double clicked.

event is the mouse event that caused the click and item is the item that received the click.

See also
  itemClick

## ◆ axisClick

void QCustomPlot::axisClick | ( | QCPAxis * | axis,
|  | QCPAxis::SelectablePart | part,
|  | QMouseEvent * | event )
| signal

This signal is emitted when an axis is clicked.

event is the mouse event that caused the click, axis is the axis that received the click and part indicates the part of the axis that was clicked.

See also
  axisDoubleClick

## ◆ axisDoubleClick

void QCustomPlot::axisDoubleClick | ( | QCPAxis * | axis,
|  | QCPAxis::SelectablePart | part,
|  | QMouseEvent * | event )
| signal

This signal is emitted when an axis is double clicked.

event is the mouse event that caused the click, axis is the axis that received the click and part indicates the part of the axis that was clicked.

See also
  axisClick

## ◆ legendClick

void QCustomPlot::legendClick | ( | QCPLegend * | legend,
|  | QCPAbstractLegendItem * | item,
|  | QMouseEvent * | event )
| signal

This signal is emitted when a legend (item) is clicked.

event is the mouse event that caused the click, legend is the legend that received the click and item is the legend item that received the click. If only the legend and no item is clicked, item is `nullptr`. This happens for a click inside the legend padding or the space between two items.

See also
  legendDoubleClick

## ◆ legendDoubleClick

void QCustomPlot::legendDoubleClick | ( | QCPLegend * | legend,
|  | QCPAbstractLegendItem * | item,
|  | QMouseEvent * | event )
| signal

This signal is emitted when a legend (item) is double clicked.

event is the mouse event that caused the click, legend is the legend that received the click and item is the legend item that received the click. If only the legend and no item is clicked, item is `nullptr`. This happens for a click inside the legend padding or the space between two items.

See also
  legendClick

## ◆ selectionChangedByUser

void QCustomPlot::selectionChangedByUser | ( |  | ) |
| signal

This signal is emitted after the user has changed the selection in the QCustomPlot, e.g. by clicking. It is not emitted when the selection state of an object has changed programmatically by a direct call to setSelected()/setSelection() on an object or by calling deselectAll.

In addition to this signal, selectable objects also provide individual signals, for example QCPAxis::selectionChanged or QCPAbstractPlottable::selectionChanged. Note that those signals are emitted even if the selection state is changed programmatically.

See the documentation of setInteractions for details about the selection mechanism.

See also
  selectedPlottables, selectedGraphs, selectedItems, selectedAxes, selectedLegends

## ◆ beforeReplot

void QCustomPlot::beforeReplot | ( |  | ) |
| signal

This signal is emitted immediately before a replot takes place (caused by a call to the slot replot).

It is safe to mutually connect the replot slot with this signal on two QCustomPlots to make them replot synchronously, it won't cause an infinite recursion.

See also
  replot, afterReplot, afterLayout

## ◆ afterLayout

void QCustomPlot::afterLayout | ( |  | ) |
| signal

This signal is emitted immediately after the layout step has been completed, which occurs right before drawing the plot. This is typically during a call to replot, and in such cases this signal is emitted in between the signals beforeReplot and afterReplot. Unlike those signals however, this signal is also emitted during off-screen painting, such as when calling toPixmap or savePdf.

The layout step queries all layouts and layout elements in the plot for their proposed size and arranges the objects accordingly as preparation for the subsequent drawing step. Through this signal, you have the opportunity to update certain things in your plot that depend crucially on the exact dimensions/positioning of layout elements such as axes and axis rects.

Warning
  However, changing any parameters of this QCustomPlot instance which would normally affect the layouting (e.g. axis range order of magnitudes, tick label sizes, etc.) will not issue a second run of the layout step. It will propagate directly to the draw step and may cause graphical inconsistencies such as overlapping objects, if sizes or positions have changed.

See also
  updateLayout, beforeReplot, afterReplot

## ◆ afterReplot

void QCustomPlot::afterReplot | ( |  | ) |
| signal

This signal is emitted immediately after a replot has taken place (caused by a call to the slot replot).

It is safe to mutually connect the replot slot with this signal on two QCustomPlots to make them replot synchronously, it won't cause an infinite recursion.

See also
  replot, beforeReplot, afterLayout

## ◆ minimumSizeHint()

QSize QCustomPlot::minimumSizeHint | ( |  | ) | const
| protectedvirtual

Returns a minimum size hint that corresponds to the minimum size of the top level layout (plotLayout). To prevent QCustomPlot from being collapsed to size/width zero, set a minimum size (setMinimumSize) either on the whole QCustomPlot or on any layout elements inside the plot. This is especially important, when placed in a QLayout where other components try to take in as much space as possible (e.g. QMdiArea).

## ◆ sizeHint()

QSize QCustomPlot::sizeHint | ( |  | ) | const
| protectedvirtual

Returns a size hint that is the same as minimumSizeHint.

## ◆ paintEvent()

void QCustomPlot::paintEvent | ( | QPaintEvent * | event | ) |
| protectedvirtual

Event handler for when the QCustomPlot widget needs repainting. This does not cause a replot, but draws the internal buffer on the widget surface.

## ◆ resizeEvent()

void QCustomPlot::resizeEvent | ( | QResizeEvent * | event | ) |
| protectedvirtual

Event handler for a resize of the QCustomPlot widget. The viewport (which becomes the outer rect of mPlotLayout) is resized appropriately. Finally a replot is performed.

## ◆ mouseDoubleClickEvent()

void QCustomPlot::mouseDoubleClickEvent | ( | QMouseEvent * | event | ) |
| protectedvirtual

Event handler for when a double click occurs. Emits the mouseDoubleClick signal, then determines the layerable under the cursor and forwards the event to it. Finally, emits the specialized signals when certain objecs are clicked (e.g. plottableDoubleClick, axisDoubleClick, etc.).

See also
  mousePressEvent, mouseReleaseEvent

## ◆ mousePressEvent()

void QCustomPlot::mousePressEvent | ( | QMouseEvent * | event | ) |
| protectedvirtual

Event handler for when a mouse button is pressed. Emits the mousePress signal.

If the current setSelectionRectMode is not QCP::srmNone, passes the event to the selection rect. Otherwise determines the layerable under the cursor and forwards the event to it.

See also
  mouseMoveEvent, mouseReleaseEvent

## ◆ mouseMoveEvent()

void QCustomPlot::mouseMoveEvent | ( | QMouseEvent * | event | ) |
| protectedvirtual

Event handler for when the cursor is moved. Emits the mouseMove signal.

If the selection rect (setSelectionRect) is currently active, the event is forwarded to it in order to update the rect geometry.

Otherwise, if a layout element has mouse capture focus (a mousePressEvent happened on top of the layout element before), the mouseMoveEvent is forwarded to that element.

See also
  mousePressEvent, mouseReleaseEvent

## ◆ mouseReleaseEvent()

void QCustomPlot::mouseReleaseEvent | ( | QMouseEvent * | event | ) |
| protectedvirtual

Event handler for when a mouse button is released. Emits the mouseRelease signal.

If the mouse was moved less than a certain threshold in any direction since the mousePressEvent, it is considered a click which causes the selection mechanism (if activated via setInteractions) to possibly change selection states accordingly. Further, specialized mouse click signals are emitted (e.g. plottableClick, axisClick, etc.)

If a layerable is the mouse capturer (a mousePressEvent happened on top of the layerable before), the mouseReleaseEvent is forwarded to that element.

See also
  mousePressEvent, mouseMoveEvent

## ◆ wheelEvent()

void QCustomPlot::wheelEvent | ( | QWheelEvent * | event | ) |
| protectedvirtual

Event handler for mouse wheel events. First, the mouseWheel signal is emitted. Then determines the affected layerable and forwards the event to it.

## ◆ draw()

void QCustomPlot::draw | ( | QCPPainter * | painter | ) |
| protectedvirtual

This function draws the entire plot, including background pixmap, with the specified painter. It does not make use of the paint buffers like replot, so this is the function typically used by saving/exporting methods such as savePdf or toPainter.

Note that it does not fill the background with the background brush (as the user may specify with setBackground(const QBrush &brush)), this is up to the respective functions calling this method.

## ◆ updateLayout()

void QCustomPlot::updateLayout | ( |  | ) |
| protectedvirtual

Performs the layout update steps defined by QCPLayoutElement::UpdatePhase, by calling QCPLayoutElement::update on the main plot layout.

Here, the layout elements calculate their positions and margins, and prepare for the following draw call.

## ◆ axisRemoved()

void QCustomPlot::axisRemoved | ( | QCPAxis * | axis | ) |
| protectedvirtual

This method is used by QCPAxisRect::removeAxis to report removed axes to the QCustomPlot so it may clear its QCustomPlot::xAxis, yAxis, xAxis2 and yAxis2 members accordingly.

## ◆ legendRemoved()

void QCustomPlot::legendRemoved | ( | QCPLegend * | legend | ) |
| protectedvirtual

This method is used by the QCPLegend destructor to report legend removal to the QCustomPlot so it may clear its QCustomPlot::legend member accordingly.

## ◆ processRectSelection()

void QCustomPlot::processRectSelection | ( | QRect | rect,
|  | QMouseEvent * | event )
| protectedvirtual

This slot is connected to the selection rect's QCPSelectionRect::accepted signal when setSelectionRectMode is set to QCP::srmSelect.

First, it determines which axis rect was the origin of the selection rect judging by the starting point of the selection. Then it goes through the plottables (QCPAbstractPlottable1D to be precise) associated with that axis rect and finds the data points that are in rect. It does this by querying their QCPAbstractPlottable1D::selectTestRect method.

Then, the actual selection is done by calling the plottables' QCPAbstractPlottable::selectEvent, placing the found selected data points in the details parameter as QVariant(QCPDataSelection). All plottables that weren't touched by rect receive a QCPAbstractPlottable::deselectEvent.

See also
  processRectZoom

## ◆ processRectZoom()

void QCustomPlot::processRectZoom | ( | QRect | rect,
|  | QMouseEvent * | event )
| protectedvirtual

This slot is connected to the selection rect's QCPSelectionRect::accepted signal when setSelectionRectMode is set to QCP::srmZoom.

It determines which axis rect was the origin of the selection rect judging by the starting point of the selection, and then zooms the axes defined via QCPAxisRect::setRangeZoomAxes to the provided rect (see QCPAxisRect::zoom).

See also
  processRectSelection

## ◆ processPointSelection()

void QCustomPlot::processPointSelection | ( | QMouseEvent * | event | ) |
| protectedvirtual

This method is called when a simple left mouse click was detected on the QCustomPlot surface.

It first determines the layerable that was hit by the click, and then calls its QCPLayerable::selectEvent. All other layerables receive a QCPLayerable::deselectEvent (unless the multi-select modifier was pressed, see setMultiSelectModifier).

In this method the hit layerable is determined a second time using layerableAt (after the one in mousePressEvent), because we want onlySelectable set to true this time. This implies that the mouse event grabber (mMouseEventLayerable) may be a different one from the clicked layerable determined here. For example, if a non-selectable layerable is in front of a selectable layerable at the click position, the front layerable will receive mouse events but the selectable one in the back will receive the QCPLayerable::selectEvent.

See also
  processRectSelection, QCPLayerable::selectTest

## ◆ registerPlottable()

bool QCustomPlot::registerPlottable | ( | QCPAbstractPlottable * | plottable | ) |
| protected

Registers the specified plottable with this QCustomPlot and, if setAutoAddPlottableToLegend is enabled, adds it to the legend (QCustomPlot::legend). QCustomPlot takes ownership of the plottable.

Returns true on success, i.e. when plottable isn't already in this plot and the parent plot of plottable is this QCustomPlot.

This method is called automatically in the QCPAbstractPlottable base class constructor.

## ◆ registerGraph()

bool QCustomPlot::registerGraph | ( | QCPGraph * | graph | ) |
| protected

In order to maintain the simplified graph interface of QCustomPlot, this method is called by the QCPGraph constructor to register itself with this QCustomPlot's internal graph list. Returns true on success, i.e. if graph is valid and wasn't already registered with this QCustomPlot.

This graph specific registration happens in addition to the call to registerPlottable by the QCPAbstractPlottable base class.

## ◆ registerItem()

bool QCustomPlot::registerItem | ( | QCPAbstractItem * | item | ) |
| protected

Registers the specified item with this QCustomPlot. QCustomPlot takes ownership of the item.

Returns true on success, i.e. when item wasn't already in the plot and the parent plot of item is this QCustomPlot.

This method is called automatically in the QCPAbstractItem base class constructor.

## ◆ updateLayerIndices()

void QCustomPlot::updateLayerIndices | ( |  | ) | const
| protected

Assigns all layers their index (QCPLayer::mIndex) in the mLayers list. This method is thus called after every operation that changes the layer indices, like layer removal, layer creation, layer moving.

## ◆ layerableAt()

QCPLayerable * QCustomPlot::layerableAt | ( | const QPointF & | pos,
|  | bool | onlySelectable,
|  | QVariant * | selectionDetails = nullptr ) const
| protected

Returns the top-most layerable at pixel position pos. If onlySelectable is set to true, only those layerables that are selectable will be considered. (Layerable subclasses communicate their selectability via the QCPLayerable::selectTest method, by returning -1.)

selectionDetails is an output parameter that contains selection specifics of the affected layerable. This is useful if the respective layerable shall be given a subsequent QCPLayerable::selectEvent (like in mouseReleaseEvent). selectionDetails usually contains information about which part of the layerable was hit, in multi-part layerables (e.g. QCPAxis::SelectablePart). If the layerable is a plottable, selectionDetails contains a QCPDataSelection instance with the single data point which is closest to pos.

See also
  layerableListAt, layoutElementAt, axisRectAt

## ◆ layerableListAt()

QList< QCPLayerable * > QCustomPlot::layerableListAt | ( | const QPointF & | pos,
|  | bool | onlySelectable,
|  | QList< QVariant > * | selectionDetails = nullptr ) const
| protected

Returns the layerables at pixel position pos. If onlySelectable is set to true, only those layerables that are selectable will be considered. (Layerable subclasses communicate their selectability via the QCPLayerable::selectTest method, by returning -1.)

The returned list is sorted by the layerable/drawing order such that the layerable that appears on top in the plot is at index 0 of the returned list. If you only need to know the top layerable, rather use layerableAt.

selectionDetails is an output parameter that contains selection specifics of the affected layerable. This is useful if the respective layerable shall be given a subsequent QCPLayerable::selectEvent (like in mouseReleaseEvent). selectionDetails usually contains information about which part of the layerable was hit, in multi-part layerables (e.g. QCPAxis::SelectablePart). If the layerable is a plottable, selectionDetails contains a QCPDataSelection instance with the single data point which is closest to pos.

See also
  layerableAt, layoutElementAt, axisRectAt

## ◆ drawBackground()

void QCustomPlot::drawBackground | ( | QCPPainter * | painter | ) |
| protected

Draws the viewport background pixmap of the plot.

If a pixmap was provided via setBackground, this function buffers the scaled version depending on setBackgroundScaled and setBackgroundScaledMode and then draws it inside the viewport with the provided painter. The scaled version is buffered in mScaledBackgroundPixmap to prevent expensive rescaling at every redraw. It is only updated, when the axis rect has changed in a way that requires a rescale of the background pixmap (this is dependent on the setBackgroundScaledMode), or when a differend axis background pixmap was set.

Note that this function does not draw a fill with the background brush (setBackground(const QBrush &brush)) beneath the pixmap.

See also
  setBackground, setBackgroundScaled, setBackgroundScaledMode

## ◆ setupPaintBuffers()

void QCustomPlot::setupPaintBuffers | ( |  | ) |
| protected

Goes through the layers and makes sure this QCustomPlot instance holds the correct number of paint buffers and that they have the correct configuration (size, pixel ratio, etc.). Allocations, reallocations and deletions of paint buffers are performed as necessary. It also associates the paint buffers with the layers, so they draw themselves into the right buffer when QCPLayer::drawToPaintBuffer is called. This means it associates adjacent QCPLayer::lmLogical layers to a mutual paint buffer and creates dedicated paint buffers for layers in QCPLayer::lmBuffered mode.

This method uses createPaintBuffer to create new paint buffers.

After this method, the paint buffers are empty (filled with `Qt::transparent`) and invalidated (so an attempt to replot only a single buffered layer causes a full replot).

This method is called in every replot call, prior to actually drawing the layers (into their associated paint buffer). If the paint buffers don't need changing/reallocating, this method basically leaves them alone and thus finishes very fast.

## ◆ createPaintBuffer()

QCPAbstractPaintBuffer * QCustomPlot::createPaintBuffer | ( |  | ) |
| protected

This method is used by setupPaintBuffers when it needs to create new paint buffers.

Depending on the current setting of setOpenGl, and the current Qt version, different backends (subclasses of QCPAbstractPaintBuffer) are created, initialized with the proper size and device pixel ratio, and returned.

## ◆ hasInvalidatedPaintBuffers()

bool QCustomPlot::hasInvalidatedPaintBuffers | ( |  | ) |
| protected

This method returns whether any of the paint buffers held by this QCustomPlot instance are invalidated.

If any buffer is invalidated, a partial replot (QCPLayer::replot) is not allowed and always causes a full replot (QCustomPlot::replot) of all layers. This is the case when for example the layer order has changed, new layers were added or removed, layer modes were changed (QCPLayer::setMode), or layerables were added or removed.

See also
  QCPAbstractPaintBuffer::setInvalidated

## ◆ setupOpenGl()

bool QCustomPlot::setupOpenGl | ( |  | ) |
| protected

When setOpenGl is set to true, this method is used to initialize OpenGL (create a context, surface, paint device).

Returns true on success.

If this method is successful, all paint buffers should be deleted and then reallocated by calling setupPaintBuffers, so the OpenGL-based paint buffer subclasses (QCPPaintBufferGlPbuffer, QCPPaintBufferGlFbo) are used for subsequent replots.

See also
  freeOpenGl

## ◆ freeOpenGl()

void QCustomPlot::freeOpenGl | ( |  | ) |
| protected

When setOpenGl is set to false, this method is used to deinitialize OpenGL (releases the context and frees resources).

After OpenGL is disabled, all paint buffers should be deleted and then reallocated by calling setupPaintBuffers, so the standard software rendering paint buffer subclass (QCPPaintBufferPixmap) is used for subsequent replots.

See also
  setupOpenGl

## Field Documentation

## ◆ xAxis

QCPAxis* QCustomPlot::xAxis

A pointer to the primary x Axis (bottom) of the main axis rect of the plot.

QCustomPlot offers convenient pointers to the axes (xAxis, yAxis, xAxis2, yAxis2) and the legend. They make it very easy working with plots that only have a single axis rect and at most one axis at each axis rect side. If you use the layout system to add multiple axis rects or multiple axes to one side, use the QCPAxisRect::axis interface to access the new axes. If one of the four default axes or the default legend is removed due to manipulation of the layout system (e.g. by removing the main axis rect), the corresponding pointers become `nullptr`.

If an axis convenience pointer is currently `nullptr` and a new axis rect or a corresponding axis is added in the place of the main axis rect, QCustomPlot resets the convenience pointers to the according new axes. Similarly the legend convenience pointer will be reset if a legend is added after the main legend was removed before.

## ◆ yAxis

QCPAxis * QCustomPlot::yAxis

A pointer to the primary y Axis (left) of the main axis rect of the plot.

QCustomPlot offers convenient pointers to the axes (xAxis, yAxis, xAxis2, yAxis2) and the legend. They make it very easy working with plots that only have a single axis rect and at most one axis at each axis rect side. If you use the layout system to add multiple axis rects or multiple axes to one side, use the QCPAxisRect::axis interface to access the new axes. If one of the four default axes or the default legend is removed due to manipulation of the layout system (e.g. by removing the main axis rect), the corresponding pointers become `nullptr`.

If an axis convenience pointer is currently `nullptr` and a new axis rect or a corresponding axis is added in the place of the main axis rect, QCustomPlot resets the convenience pointers to the according new axes. Similarly the legend convenience pointer will be reset if a legend is added after the main legend was removed before.

## ◆ xAxis2

QCPAxis * QCustomPlot::xAxis2

A pointer to the secondary x Axis (top) of the main axis rect of the plot. Secondary axes are invisible by default. Use QCPAxis::setVisible to change this (or use QCPAxisRect::setupFullAxesBox).

QCustomPlot offers convenient pointers to the axes (xAxis, yAxis, xAxis2, yAxis2) and the legend. They make it very easy working with plots that only have a single axis rect and at most one axis at each axis rect side. If you use the layout system to add multiple axis rects or multiple axes to one side, use the QCPAxisRect::axis interface to access the new axes. If one of the four default axes or the default legend is removed due to manipulation of the layout system (e.g. by removing the main axis rect), the corresponding pointers become `nullptr`.

If an axis convenience pointer is currently `nullptr` and a new axis rect or a corresponding axis is added in the place of the main axis rect, QCustomPlot resets the convenience pointers to the according new axes. Similarly the legend convenience pointer will be reset if a legend is added after the main legend was removed before.

## ◆ yAxis2

QCPAxis * QCustomPlot::yAxis2

A pointer to the secondary y Axis (right) of the main axis rect of the plot. Secondary axes are invisible by default. Use QCPAxis::setVisible to change this (or use QCPAxisRect::setupFullAxesBox).

QCustomPlot offers convenient pointers to the axes (xAxis, yAxis, xAxis2, yAxis2) and the legend. They make it very easy working with plots that only have a single axis rect and at most one axis at each axis rect side. If you use the layout system to add multiple axis rects or multiple axes to one side, use the QCPAxisRect::axis interface to access the new axes. If one of the four default axes or the default legend is removed due to manipulation of the layout system (e.g. by removing the main axis rect), the corresponding pointers become `nullptr`.

If an axis convenience pointer is currently `nullptr` and a new axis rect or a corresponding axis is added in the place of the main axis rect, QCustomPlot resets the convenience pointers to the according new axes. Similarly the legend convenience pointer will be reset if a legend is added after the main legend was removed before.

## ◆ legend

QCPLegend* QCustomPlot::legend

A pointer to the default legend of the main axis rect. The legend is invisible by default. Use QCPLegend::setVisible to change this.

QCustomPlot offers convenient pointers to the axes (xAxis, yAxis, xAxis2, yAxis2) and the legend. They make it very easy working with plots that only have a single axis rect and at most one axis at each axis rect side. If you use the layout system to add multiple legends to the plot, use the layout system interface to access the new legend. For example, legends can be placed inside an axis rect's inset layout, and must then also be accessed via the inset layout. If the default legend is removed due to manipulation of the layout system (e.g. by removing the main axis rect), the corresponding pointer becomes `nullptr`.

If an axis convenience pointer is currently `nullptr` and a new axis rect or a corresponding axis is added in the place of the main axis rect, QCustomPlot resets the convenience pointers to the according new axes. Similarly the legend convenience pointer will be reset if a legend is added after the main legend was removed before.

The documentation for this class was generated from the following files:

- src/core.h
- src/core.cpp