QCPLayer Class Reference

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

#include <qcustomplot.h>

Inheritance diagram for QCPLayer:

Public Member Functions
	QCPLayer (QCustomPlot *parentPlot, const QString &layerName)
	Creates a new QCPLayer instance.
	~QCPLayer ()
QCustomPlot *	parentPlot () const
QString	name () const
int	index () const
	Returns the index this layer has in the QCustomPlot.
QList< QCPLayerable * >	children () const
	Returns a list of all layerables on this layer.
bool	visible () const
void	setVisible (bool visible)
	Sets whether this layer is visible or not.

Protected Member Functions
void	addChild (QCPLayerable *layerable, bool prepend)
void	removeChild (QCPLayerable *layerable)

Protected Attributes
QCustomPlot *	mParentPlot
QString	mName
int	mIndex
QList< QCPLayerable * >	mChildren
bool	mVisible

Friends
class	QCustomPlot
class	QCPLayerable

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.

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.

Initially, QCustomPlot has five layers: "background", "grid", "main", "axes" and "legend" (in that order). The top two layers "axes" and "legend" contain the default axes and legend, so they will be drawn on top. 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 ordering of objects is easy: Create a new layer in the position you want it to be, 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.

Definition at line 364 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 751 of file qcustomplot.cpp.

~QCPLayer()

QCPLayer::~QCPLayer

(

)

Definition at line 762 of file qcustomplot.cpp.

Member Function Documentation

addChild()

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

protected

Definition at line 799 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 382 of file qcustomplot.h.

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 381 of file qcustomplot.h.

name()

QString QCPLayer::name ( ) const

inline

Definition at line 380 of file qcustomplot.h.

parentPlot()

QCustomPlot * QCPLayer::parentPlot ( ) const

inline

Definition at line 379 of file qcustomplot.h.

removeChild()

void QCPLayer::removeChild ( QCPLayerable *  layerable )

protected

Definition at line 820 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 784 of file qcustomplot.cpp.

visible()

bool QCPLayer::visible ( ) const

inline

Definition at line 383 of file qcustomplot.h.

Friends And Related Symbol Documentation

QCPLayerable

friend class QCPLayerable

friend

Definition at line 404 of file qcustomplot.h.

QCustomPlot

friend class QCustomPlot

friend

Definition at line 403 of file qcustomplot.h.

Member Data Documentation

mChildren

QList<QCPLayerable*> QCPLayer::mChildren

protected

Definition at line 393 of file qcustomplot.h.

mIndex

int QCPLayer::mIndex

protected

Definition at line 392 of file qcustomplot.h.

mName

QString QCPLayer::mName

protected

Definition at line 391 of file qcustomplot.h.

mParentPlot

QCustomPlot* QCPLayer::mParentPlot

protected

Definition at line 390 of file qcustomplot.h.

mVisible

bool QCPLayer::mVisible

protected

Definition at line 394 of file qcustomplot.h.

---

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

• icub-main/src/tools/skinManagerGui/qcustomplot.h
• icub-main/src/tools/skinManagerGui/qcustomplot.cpp