QCPLayer Class Reference

Inheritance diagram for QCPLayer:

Public Types
enum	LayerMode { lmLogical , lmBuffered }

Public Member Functions
	QCPLayer (QCustomPlot *parentPlot, const QString &layerName)
QList< QCPLayerable * >	children () const
int	index () const
LayerMode	mode () const
QString	name () const
QCustomPlot *	parentPlot () const
void	replot ()
void	setMode (LayerMode mode)
void	setVisible (bool visible)
bool	visible () const
Public Member Functions inherited from QObject
	QObject (QObject *parent)
QBindable< QString >	bindableObjectName ()
bool	blockSignals (bool block)
const QObjectList &	children () const const
QMetaObject::Connection	connect (const QObject *sender, const char *signal, const char *method, Qt::ConnectionType type) const const
void	deleteLater ()
void	destroyed (QObject *obj)
bool	disconnect (const char *signal, const QObject *receiver, const char *method) const const
bool	disconnect (const QObject *receiver, const char *method) const const
void	dumpObjectInfo () const const
void	dumpObjectTree () const const
QList< QByteArray >	dynamicPropertyNames () const const
virtual bool	event (QEvent *e)
virtual bool	eventFilter (QObject *watched, QEvent *event)
T	findChild (const QString &name, Qt::FindChildOptions options) const const
QList< T >	findChildren (const QRegularExpression &re, Qt::FindChildOptions options) const const
QList< T >	findChildren (const QString &name, Qt::FindChildOptions options) const const
QList< T >	findChildren (Qt::FindChildOptions options) const const
bool	inherits (const char *className) const const
void	installEventFilter (QObject *filterObj)
bool	isQuickItemType () const const
bool	isWidgetType () const const
bool	isWindowType () const const
void	killTimer (int id)
virtual const QMetaObject *	metaObject () const const
void	moveToThread (QThread *targetThread)
QString	objectName () const const
void	objectNameChanged (const QString &objectName)
QObject *	parent () const const
QVariant	property (const char *name) const const
	Q_CLASSINFO (Name, Value)
	Q_EMIT Q_EMIT
	Q_ENUM (...)
	Q_ENUM_NS (...)
	Q_ENUMS (...)
	Q_FLAG (...)
	Q_FLAG_NS (...)
	Q_FLAGS (...)
	Q_GADGET Q_GADGET
	Q_GADGET_EXPORT (EXPORT_MACRO)
	Q_INTERFACES (...)
	Q_INVOKABLE Q_INVOKABLE
	Q_MOC_INCLUDE Q_MOC_INCLUDE
	Q_NAMESPACE Q_NAMESPACE
	Q_NAMESPACE_EXPORT (EXPORT_MACRO)
	Q_OBJECT Q_OBJECT
	Q_PROPERTY (...)
	Q_REVISION Q_REVISION
	Q_SET_OBJECT_NAME (Object)
	Q_SIGNAL Q_SIGNAL
	Q_SIGNALS Q_SIGNALS
	Q_SLOT Q_SLOT
	Q_SLOTS Q_SLOTS
T	qobject_cast (const QObject *object)
T	qobject_cast (QObject *object)
	QT_NO_NARROWING_CONVERSIONS_IN_CONNECT QT_NO_NARROWING_CONVERSIONS_IN_CONNECT
void	removeEventFilter (QObject *obj)
void	setObjectName (const QString &name)
void	setObjectName (QAnyStringView name)
void	setParent (QObject *parent)
bool	setProperty (const char *name, const QVariant &value)
bool	setProperty (const char *name, QVariant &&value)
bool	signalsBlocked () const const
int	startTimer (int interval, Qt::TimerType timerType)
int	startTimer (std::chrono::milliseconds interval, Qt::TimerType timerType)
QThread *	thread () const const

Protected Member Functions
void	addChild (QCPLayerable *layerable, bool prepend)
void	draw (QCPPainter *painter)
void	drawToPaintBuffer ()
void	removeChild (QCPLayerable *layerable)
Protected Member Functions inherited from QObject
virtual void	childEvent (QChildEvent *event)
virtual void	connectNotify (const QMetaMethod &signal)
virtual void	customEvent (QEvent *event)
virtual void	disconnectNotify (const QMetaMethod &signal)
bool	isSignalConnected (const QMetaMethod &signal) const const
int	receivers (const char *signal) const const
QObject *	sender () const const
int	senderSignalIndex () const const
virtual void	timerEvent (QTimerEvent *event)

Protected Attributes
QList< QCPLayerable * >	mChildren
int	mIndex
LayerMode	mMode
QString	mName
QWeakPointer< QCPAbstractPaintBuffer >	mPaintBuffer
QCustomPlot *	mParentPlot
bool	mVisible

Additional Inherited Members
Properties inherited from QObject
	objectName
Static Public Member Functions inherited from QObject
QMetaObject::Connection	connect (const QObject *sender, const char *signal, const QObject *receiver, const char *method, Qt::ConnectionType type)
QMetaObject::Connection	connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type)
QMetaObject::Connection	connect (const QObject *sender, PointerToMemberFunction signal, const QObject *context, Functor functor, Qt::ConnectionType type)
QMetaObject::Connection	connect (const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method, Qt::ConnectionType type)
QMetaObject::Connection	connect (const QObject *sender, PointerToMemberFunction signal, Functor functor)
bool	disconnect (const QMetaObject::Connection &connection)
bool	disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *method)
bool	disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method)
bool	disconnect (const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method)
QString	tr (const char *sourceText, const char *disambiguation, int n)
Public Attributes inherited from QObject
typedef	QObjectList

Detailed Description

A layer that may contain objects, to control the rendering order.

The Layering system of QCustomPlot is the mechanism to control the rendering order of the elements inside the plot.

It is based on the two classes QCPLayer and QCPLayerable. QCustomPlot holds an ordered list of one or more instances of QCPLayer (see QCustomPlot::addLayer, QCustomPlot::layer, QCustomPlot::moveLayer, etc.). When replotting, QCustomPlot goes through the list of layers bottom to top and successively draws the layerables of the layers into the paint buffer(s).

A QCPLayer contains an ordered list of QCPLayerable instances. QCPLayerable is an abstract base class from which almost all visible objects derive, like axes, grids, graphs, items, etc.

Default layers

Initially, QCustomPlot has six layers: "background", "grid", "main", "axes", "legend" and "overlay" (in that order). On top is the "overlay" layer, which only contains the QCustomPlot's selection rect (QCustomPlot::selectionRect). The next two layers "axes" and "legend" contain the default axes and legend, so they will be drawn above plottables. In the middle, there is the "main" layer. It is initially empty and set as the current layer (see QCustomPlot::setCurrentLayer). This means, all new plottables, items etc. are created on this layer by default. Then comes the "grid" layer which contains the QCPGrid instances (which belong tightly to QCPAxis, see QCPAxis::grid). The Axis rect background shall be drawn behind everything else, thus the default QCPAxisRect instance is placed on the "background" layer. Of course, the layer affiliation of the individual objects can be changed as required (QCPLayerable::setLayer).

Controlling the rendering order via layers

Controlling the ordering of layerables in the plot is easy: Create a new layer in the position you want the layerable to be in, e.g. above "main", with QCustomPlot::addLayer. Then set the current layer with QCustomPlot::setCurrentLayer to that new layer and finally create the objects normally. They will be placed on the new layer automatically, due to the current layer setting. Alternatively you could have also ignored the current layer setting and just moved the objects with QCPLayerable::setLayer to the desired layer after creating them.

It is also possible to move whole layers. For example, If you want the grid to be shown in front of all plottables/items on the "main" layer, just move it above "main" with QCustomPlot::moveLayer.

The rendering order within one layer is simply by order of creation or insertion. The item created last (or added last to the layer), is drawn on top of all other objects on that layer.

When a layer is deleted, the objects on it are not deleted with it, but fall on the layer below the deleted layer, see QCustomPlot::removeLayer.

Replotting only a specific layer

If the layer mode (setMode) is set to lmBuffered, you can replot only this specific layer by calling replot. In certain situations this can provide better replot performance, compared with a full replot of all layers. Upon creation of a new layer, the layer mode is initialized to lmLogical. The only layer that is set to lmBuffered in a new QCustomPlot instance is the "overlay" layer, containing the selection rect.

Definition at line 625 of file qcustomplot.h.

Member Enumeration Documentation

LayerMode

enum QCPLayer::LayerMode

Defines the different rendering modes of a layer. Depending on the mode, certain layers can be replotted individually, without the need to replot (possibly complex) layerables on other layers.

See also

setMode

Enumerator
lmLogical	Layer is used only for rendering order, and shares paint buffer with all other adjacent logical layers.
lmBuffered	Layer has its own paint buffer and may be replotted individually (see replot).

Definition at line 645 of file qcustomplot.h.

Constructor & Destructor Documentation

QCPLayer()

QCPLayer::QCPLayer	(	QCustomPlot *	parentPlot,
		const QString &	layerName )

Creates a new QCPLayer instance.

Normally you shouldn't directly instantiate layers, use QCustomPlot::addLayer instead.

Warning

It is not checked that layerName is actually a unique layer name in parentPlot. This check is only performed by QCustomPlot::addLayer.

Definition at line 1049 of file qcustomplot.cpp.

~QCPLayer()

QCPLayer::~QCPLayer ( )

virtual

Definition at line 1061 of file qcustomplot.cpp.

Member Function Documentation

addChild()

void QCPLayer::addChild ( QCPLayerable * layerable, bool prepend )

protected

Adds the layerable to the list of this layer. If prepend is set to true, the layerable will be prepended to the list, i.e. be drawn beneath the other layerables already in the list.

This function does not change the mLayer member of layerable to this layer. (Use QCPLayerable::setLayer to change the layer of an object, not this function.)

See also

removeChild

Definition at line 1206 of file qcustomplot.cpp.

children()

QList< QCPLayerable * > QCPLayer::children ( ) const

inline

Returns a list of all layerables on this layer. The order corresponds to the rendering order: layerables with higher indices are drawn above layerables with lower indices.

Definition at line 657 of file qcustomplot.h.

draw()

void QCPLayer::draw ( QCPPainter * painter )

protected

Draws the contents of this layer with the provided painter.

See also

replot, drawToPaintBuffer

Definition at line 1125 of file qcustomplot.cpp.

drawToPaintBuffer()

void QCPLayer::drawToPaintBuffer ( )

protected

Draws the contents of this layer into the paint buffer which is associated with this layer. The association is established by the parent QCustomPlot, which manages all paint buffers (see QCustomPlot::setupPaintBuffers).

See also

draw

Definition at line 1148 of file qcustomplot.cpp.

index()

int QCPLayer::index ( ) const

inline

Returns the index this layer has in the QCustomPlot. The index is the integer number by which this layer can be accessed via QCustomPlot::layer.

Layers with higher indices will be drawn above layers with lower indices.

Definition at line 656 of file qcustomplot.h.

mode()

LayerMode QCPLayer::mode ( ) const

inline

Definition at line 659 of file qcustomplot.h.

name()

QString QCPLayer::name ( ) const

inline

Definition at line 655 of file qcustomplot.h.

parentPlot()

QCustomPlot * QCPLayer::parentPlot ( ) const

inline

Definition at line 654 of file qcustomplot.h.

removeChild()

void QCPLayer::removeChild ( QCPLayerable * layerable )

protected

Removes the layerable from the list of this layer.

This function does not change the mLayer member of layerable. (Use QCPLayerable::setLayer to change the layer of an object, not this function.)

See also

addChild

Definition at line 1229 of file qcustomplot.cpp.

replot()

void QCPLayer::replot

(

)

If the layer mode (setMode) is set to lmBuffered, this method allows replotting only the layerables on this specific layer, without the need to replot all other layers (as a call to QCustomPlot::replot would do).

QCustomPlot also makes sure to replot all layers instead of only this one, if the layer ordering or any layerable-layer-association has changed since the last full replot and any other paint buffers were thus invalidated.

If the layer mode is lmLogical however, this method simply calls QCustomPlot::replot on the parent QCustomPlot instance.

See also

draw

Definition at line 1180 of file qcustomplot.cpp.

setMode()

void QCPLayer::setMode

(

QCPLayer::LayerMode

mode

)

Sets the rendering mode of this layer.

If mode is set to lmBuffered for a layer, it will be given a dedicated paint buffer by the parent QCustomPlot instance. This means it may be replotted individually by calling QCPLayer::replot, without needing to replot all other layers.

Layers which are set to lmLogical (the default) are used only to define the rendering order and can't be replotted individually.

Note that each layer which is set to lmBuffered requires additional paint buffers for the layers below, above and for the layer itself. This increases the memory consumption and (slightly) decreases the repainting speed because multiple paint buffers need to be joined. So you should carefully choose which layers benefit from having their own paint buffer. A typical example would be a layer which contains certain layerables (e.g. items) that need to be changed and thus replotted regularly, while all other layerables on other layers stay static. By default, only the topmost layer called "overlay" is in mode lmBuffered, and contains the selection rect.

See also

replot

Definition at line 1109 of file qcustomplot.cpp.

setVisible()

void QCPLayer::setVisible

(

bool

visible

)

Sets whether this layer is visible or not. If visible is set to false, all layerables on this layer will be invisible.

This function doesn't change the visibility property of the layerables (QCPLayerable::setVisible), but the QCPLayerable::realVisibility of each layerable takes the visibility of the parent layer into account.

Definition at line 1083 of file qcustomplot.cpp.

visible()

bool QCPLayer::visible ( ) const

inline

Definition at line 658 of file qcustomplot.h.

Member Data Documentation

mChildren

QList<QCPLayerable*> QCPLayer::mChildren

protected

Definition at line 673 of file qcustomplot.h.

mIndex

int QCPLayer::mIndex

protected

Definition at line 672 of file qcustomplot.h.

mMode

LayerMode QCPLayer::mMode

protected

Definition at line 675 of file qcustomplot.h.

mName

QString QCPLayer::mName

protected

Definition at line 671 of file qcustomplot.h.

mPaintBuffer

QWeakPointer<QCPAbstractPaintBuffer> QCPLayer::mPaintBuffer

protected

Definition at line 678 of file qcustomplot.h.

mParentPlot

QCustomPlot* QCPLayer::mParentPlot

protected

Definition at line 670 of file qcustomplot.h.

mVisible

bool QCPLayer::mVisible

protected

Definition at line 674 of file qcustomplot.h.

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

• qcustomplot.h
• qcustomplot.cpp