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QCPBars Class Reference

A plottable representing a bar chart in a plot. More...

Inheritance diagram for QCPBars:
Inheritance graph

Public Types

enum  WidthType
 

Public Functions

 QCPBars (QCPAxis *keyAxis, QCPAxis *valueAxis)
 
double width () const
 
WidthType widthType () const
 
QCPBarsGroupbarsGroup () const
 
double baseValue () const
 
double stackingGap () const
 
QCPBarsbarBelow () const
 
QCPBarsbarAbove () const
 
QSharedPointer< QCPBarsDataContainerdata () const
 
void setData (QSharedPointer< QCPBarsDataContainer > data)
 
void setData (const QVector< double > &keys, const QVector< double > &values, bool alreadySorted=false)
 
void setWidth (double width)
 
void setWidthType (WidthType widthType)
 
void setBarsGroup (QCPBarsGroup *barsGroup)
 
void setBaseValue (double baseValue)
 
void setStackingGap (double pixels)
 
void addData (const QVector< double > &keys, const QVector< double > &values, bool alreadySorted=false)
 
void addData (double key, double value)
 
void moveBelow (QCPBars *bars)
 
void moveAbove (QCPBars *bars)
 
virtual QCPDataSelection selectTestRect (const QRectF &rect, bool onlySelectable) const
 
virtual double selectTest (const QPointF &pos, bool onlySelectable, QVariant *details=nullptr) const
 
virtual QCPRange getKeyRange (bool &foundRange, QCP::SignDomain inSignDomain=QCP::sdBoth) const
 
virtual QCPRange getValueRange (bool &foundRange, QCP::SignDomain inSignDomain=QCP::sdBoth, const QCPRange &inKeyRange=QCPRange()) const
 
virtual QPointF dataPixelPosition (int index) const
 
- Public Functions inherited from QCPAbstractPlottable1D< QCPBarsData >
 QCPAbstractPlottable1D (QCPAxis *keyAxis, QCPAxis *valueAxis)
 
virtual int dataCount () const
 
virtual double dataMainKey (int index) const
 
virtual double dataSortKey (int index) const
 
virtual double dataMainValue (int index) const
 
virtual QCPRange dataValueRange (int index) const
 
virtual bool sortKeyIsMainKey () const
 
virtual int findBegin (double sortKey, bool expandedRange=true) const
 
virtual int findEnd (double sortKey, bool expandedRange=true) const
 
virtual QCPPlottableInterface1Dinterface1D ()
 
- Public Functions inherited from QCPAbstractPlottable
 QCPAbstractPlottable (QCPAxis *keyAxis, QCPAxis *valueAxis)
 
QString name () const
 
bool antialiasedFill () const
 
bool antialiasedScatters () const
 
QPen pen () const
 
QBrush brush () const
 
QCPAxiskeyAxis () const
 
QCPAxisvalueAxis () const
 
QCP::SelectionType selectable () const
 
bool selected () const
 
QCPDataSelection selection () const
 
QCPSelectionDecoratorselectionDecorator () const
 
void setName (const QString &name)
 
void setAntialiasedFill (bool enabled)
 
void setAntialiasedScatters (bool enabled)
 
void setPen (const QPen &pen)
 
void setBrush (const QBrush &brush)
 
void setKeyAxis (QCPAxis *axis)
 
void setValueAxis (QCPAxis *axis)
 
Q_SLOT void setSelectable (QCP::SelectionType selectable)
 
Q_SLOT void setSelection (QCPDataSelection selection)
 
void setSelectionDecorator (QCPSelectionDecorator *decorator)
 
void coordsToPixels (double key, double value, double &x, double &y) const
 
const QPointF coordsToPixels (double key, double value) const
 
void pixelsToCoords (double x, double y, double &key, double &value) const
 
void pixelsToCoords (const QPointF &pixelPos, double &key, double &value) const
 
void rescaleAxes (bool onlyEnlarge=false) const
 
void rescaleKeyAxis (bool onlyEnlarge=false) const
 
void rescaleValueAxis (bool onlyEnlarge=false, bool inKeyRange=false) const
 
bool addToLegend (QCPLegend *legend)
 
bool addToLegend ()
 
bool removeFromLegend (QCPLegend *legend) const
 
bool removeFromLegend () const
 
- Public Functions inherited from QCPLayerable
 QCPLayerable (QCustomPlot *plot, QString targetLayer=QString(), QCPLayerable *parentLayerable=nullptr)
 
bool visible () const
 
QCustomPlotparentPlot () const
 
QCPLayerableparentLayerable () const
 
QCPLayerlayer () const
 
bool antialiased () const
 
void setVisible (bool on)
 
Q_SLOT bool setLayer (QCPLayer *layer)
 
bool setLayer (const QString &layerName)
 
void setAntialiased (bool enabled)
 
bool realVisibility () const
 

Protected Functions

virtual void draw (QCPPainter *painter)
 
virtual void drawLegendIcon (QCPPainter *painter, const QRectF &rect) const
 
void getVisibleDataBounds (QCPBarsDataContainer::const_iterator &begin, QCPBarsDataContainer::const_iterator &end) const
 
QRectF getBarRect (double key, double value) const
 
void getPixelWidth (double key, double &lower, double &upper) const
 
double getStackedBaseValue (double key, bool positive) const
 
- Protected Functions inherited from QCPAbstractPlottable1D< QCPBarsData >
void getDataSegments (QList< QCPDataRange > &selectedSegments, QList< QCPDataRange > &unselectedSegments) const
 
void drawPolyline (QCPPainter *painter, const QVector< QPointF > &lineData) const
 
- Protected Functions inherited from QCPAbstractPlottable
virtual QRect clipRect () const
 
virtual QCP::Interaction selectionCategory () const
 
void applyDefaultAntialiasingHint (QCPPainter *painter) const
 
virtual void selectEvent (QMouseEvent *event, bool additive, const QVariant &details, bool *selectionStateChanged)
 
virtual void deselectEvent (bool *selectionStateChanged)
 
void applyFillAntialiasingHint (QCPPainter *painter) const
 
void applyScattersAntialiasingHint (QCPPainter *painter) const
 
- Protected Functions inherited from QCPLayerable
virtual void parentPlotInitialized (QCustomPlot *parentPlot)
 
virtual void mousePressEvent (QMouseEvent *event, const QVariant &details)
 
virtual void mouseMoveEvent (QMouseEvent *event, const QPointF &startPos)
 
virtual void mouseReleaseEvent (QMouseEvent *event, const QPointF &startPos)
 
virtual void mouseDoubleClickEvent (QMouseEvent *event, const QVariant &details)
 
virtual void wheelEvent (QWheelEvent *event)
 
void initializeParentPlot (QCustomPlot *parentPlot)
 
void setParentLayerable (QCPLayerable *parentLayerable)
 
bool moveToLayer (QCPLayer *layer, bool prepend)
 
void applyAntialiasingHint (QCPPainter *painter, bool localAntialiased, QCP::AntialiasedElement overrideElement) const
 

Protected Static Functions

static void connectBars (QCPBars *lower, QCPBars *upper)
 

Additional Inherited Members

- Signals inherited from QCPAbstractPlottable
void selectionChanged (bool selected)
 
void selectionChanged (const QCPDataSelection &selection)
 
void selectableChanged (QCP::SelectionType selectable)
 
- Signals inherited from QCPLayerable
void layerChanged (QCPLayer *newLayer)
 

Detailed Description

A plottable representing a bar chart in a plot.

QCPBars.png

To plot data, assign it with the setData or addData functions.

Changing the appearance

The appearance of the bars is determined by the pen and the brush (setPen, setBrush). The width of the individual bars can be controlled with setWidthType and setWidth.

Bar charts are stackable. This means, two QCPBars plottables can be placed on top of each other (see QCPBars::moveAbove). So when two bars are at the same key position, they will appear stacked.

If you would like to group multiple QCPBars plottables together so they appear side by side as shown below, use QCPBarsGroup.

QCPBarsGroup.png

Usage

Like all data representing objects in QCustomPlot, the QCPBars is a plottable (QCPAbstractPlottable). So the plottable-interface of QCustomPlot applies (QCustomPlot::plottable, QCustomPlot::removePlottable, etc.)

Usually, you first create an instance:

QCPBars *newBars = new QCPBars(customPlot->xAxis, customPlot->yAxis);

which registers it with the QCustomPlot instance of the passed axes. Note that this QCustomPlot instance takes ownership of the plottable, so do not delete it manually but use QCustomPlot::removePlottable() instead. The newly created plottable can be modified, e.g.:

newBars->setName("Country population");
newBars->setData(xData, yData);

Member Enumeration Documentation

§ WidthType

Defines the ways the width of the bar can be specified. Thus it defines what the number passed to setWidth actually means.

See also
setWidthType, setWidth
Enumerator
wtAbsolute 

Bar width is in absolute pixels.

wtAxisRectRatio 

Bar width is given by a fraction of the axis rect size.

wtPlotCoords 

Bar width is in key coordinates and thus scales with the key axis range.

Constructor & Destructor Documentation

§ QCPBars()

QCPBars::QCPBars ( QCPAxis keyAxis,
QCPAxis valueAxis 
)
explicit

Constructs a bar chart which uses keyAxis as its key axis ("x") and valueAxis as its value axis ("y"). keyAxis and valueAxis must reside in the same QCustomPlot instance and not have the same orientation. If either of these restrictions is violated, a corresponding message is printed to the debug output (qDebug), the construction is not aborted, though.

The created QCPBars is automatically registered with the QCustomPlot instance inferred from keyAxis. This QCustomPlot instance takes ownership of the QCPBars, so do not delete it manually but use QCustomPlot::removePlottable() instead.

Member Function Documentation

§ barBelow()

QCPBars * QCPBars::barBelow ( ) const
inline

Returns the bars plottable that is directly below this bars plottable. If there is no such plottable, returns nullptr.

See also
barAbove, moveBelow, moveAbove

§ barAbove()

QCPBars * QCPBars::barAbove ( ) const
inline

Returns the bars plottable that is directly above this bars plottable. If there is no such plottable, returns nullptr.

See also
barBelow, moveBelow, moveAbove

§ data()

QSharedPointer< QCPBarsDataContainer > QCPBars::data ( ) const
inline

Returns a shared pointer to the internal data storage of type QCPBarsDataContainer. You may use it to directly manipulate the data, which may be more convenient and faster than using the regular setData or addData methods.

§ setData() [1/2]

void QCPBars::setData ( QSharedPointer< QCPBarsDataContainer data)

This is an overloaded function.

Replaces the current data container with the provided data container.

Since a QSharedPointer is used, multiple QCPBars may share the same data container safely. Modifying the data in the container will then affect all bars that share the container. Sharing can be achieved by simply exchanging the data containers wrapped in shared pointers:

bars2->setData(bars1->data()); // bars1 and bars2 now share data container

If you do not wish to share containers, but create a copy from an existing container, rather use the QCPDataContainer<DataType>::set method on the bar's data container directly:

bars2->data()->set(*bars1->data()); // bars2 now has copy of bars1's data in its container
See also
addData

§ setData() [2/2]

void QCPBars::setData ( const QVector< double > &  keys,
const QVector< double > &  values,
bool  alreadySorted = false 
)

This is an overloaded function.

Replaces the current data with the provided points in keys and values. The provided vectors should have equal length. Else, the number of added points will be the size of the smallest vector.

If you can guarantee that the passed data points are sorted by keys in ascending order, you can set alreadySorted to true, to improve performance by saving a sorting run.

See also
addData

§ setWidth()

void QCPBars::setWidth ( double  width)

Sets the width of the bars.

How the number passed as width is interpreted (e.g. screen pixels, plot coordinates,...), depends on the currently set width type, see setWidthType and WidthType.

§ setWidthType()

void QCPBars::setWidthType ( QCPBars::WidthType  widthType)

Sets how the width of the bars is defined. See the documentation of WidthType for an explanation of the possible values for widthType.

The default value is wtPlotCoords.

See also
setWidth

§ setBarsGroup()

void QCPBars::setBarsGroup ( QCPBarsGroup barsGroup)

Sets to which QCPBarsGroup this QCPBars instance belongs to. Alternatively, you can also use QCPBarsGroup::append.

To remove this QCPBars from any group, set barsGroup to nullptr.

§ setBaseValue()

void QCPBars::setBaseValue ( double  baseValue)

Sets the base value of this bars plottable.

The base value defines where on the value coordinate the bars start. How far the bars extend from the base value is given by their individual value data. For example, if the base value is set to 1, a bar with data value 2 will have its lowest point at value coordinate 1 and highest point at 3.

For stacked bars, only the base value of the bottom-most QCPBars has meaning.

The default base value is 0.

§ setStackingGap()

void QCPBars::setStackingGap ( double  pixels)

If this bars plottable is stacked on top of another bars plottable (moveAbove), this method allows specifying a distance in pixels, by which the drawn bar rectangles will be separated by the bars below it.

§ addData() [1/2]

void QCPBars::addData ( const QVector< double > &  keys,
const QVector< double > &  values,
bool  alreadySorted = false 
)

This is an overloaded function.

Adds the provided points in keys and values to the current data. The provided vectors should have equal length. Else, the number of added points will be the size of the smallest vector.

If you can guarantee that the passed data points are sorted by keys in ascending order, you can set alreadySorted to true, to improve performance by saving a sorting run.

Alternatively, you can also access and modify the data directly via the data method, which returns a pointer to the internal data container.

§ addData() [2/2]

void QCPBars::addData ( double  key,
double  value 
)

This is an overloaded function. Adds the provided data point as key and value to the current data.

Alternatively, you can also access and modify the data directly via the data method, which returns a pointer to the internal data container.

§ moveBelow()

void QCPBars::moveBelow ( QCPBars bars)

Moves this bars plottable below bars. In other words, the bars of this plottable will appear below the bars of bars. The move target bars must use the same key and value axis as this plottable.

Inserting into and removing from existing bar stacking is handled gracefully. If bars already has a bars object below itself, this bars object is inserted between the two. If this bars object is already between two other bars, the two other bars will be stacked on top of each other after the operation.

To remove this bars plottable from any stacking, set bars to nullptr.

See also
moveBelow, barAbove, barBelow

§ moveAbove()

void QCPBars::moveAbove ( QCPBars bars)

Moves this bars plottable above bars. In other words, the bars of this plottable will appear above the bars of bars. The move target bars must use the same key and value axis as this plottable.

Inserting into and removing from existing bar stacking is handled gracefully. If bars already has a bars object above itself, this bars object is inserted between the two. If this bars object is already between two other bars, the two other bars will be stacked on top of each other after the operation.

To remove this bars plottable from any stacking, set bars to nullptr.

See also
moveBelow, barBelow, barAbove

§ selectTestRect()

QCPDataSelection QCPBars::selectTestRect ( const QRectF &  rect,
bool  onlySelectable 
) const
virtual

Returns a data selection containing all the data points of this plottable which are contained (or hit by) rect. This is used mainly in the selection rect interaction for data selection (data selection mechanism).

If onlySelectable is true, an empty QCPDataSelection is returned if this plottable is not selectable (i.e. if QCPAbstractPlottable::setSelectable is QCP::stNone).

Note
rect must be a normalized rect (positive or zero width and height). This is especially important when using the rect of QCPSelectionRect::accepted, which is not necessarily normalized. Use QRect::normalized() when passing a rect which might not be normalized.

Reimplemented from QCPAbstractPlottable1D< QCPBarsData >.

§ selectTest()

double QCPBars::selectTest ( const QPointF &  pos,
bool  onlySelectable,
QVariant *  details = nullptr 
) const
virtual

Implements a selectTest specific to this plottable's point geometry.

If details is not 0, it will be set to a QCPDataSelection, describing the closest data point to pos.

For general information about this virtual method, see the base class implementation. QCPAbstractPlottable::selectTest

Reimplemented from QCPAbstractPlottable1D< QCPBarsData >.

§ getKeyRange()

QCPRange QCPBars::getKeyRange ( bool &  foundRange,
QCP::SignDomain  inSignDomain = QCP::sdBoth 
) const
virtual

Returns the coordinate range that all data in this plottable span in the key axis dimension. For logarithmic plots, one can set inSignDomain to either QCP::sdNegative or QCP::sdPositive in order to restrict the returned range to that sign domain. E.g. when only negative range is wanted, set inSignDomain to QCP::sdNegative and all positive points will be ignored for range calculation. For no restriction, just set inSignDomain to QCP::sdBoth (default). foundRange is an output parameter that indicates whether a range could be found or not. If this is false, you shouldn't use the returned range (e.g. no points in data).

Note that foundRange is not the same as QCPRange::validRange, since the range returned by this function may have size zero (e.g. when there is only one data point). In this case foundRange would return true, but the returned range is not a valid range in terms of QCPRange::validRange.

See also
rescaleAxes, getValueRange

Implements QCPAbstractPlottable.

§ getValueRange()

QCPRange QCPBars::getValueRange ( bool &  foundRange,
QCP::SignDomain  inSignDomain = QCP::sdBoth,
const QCPRange inKeyRange = QCPRange() 
) const
virtual

Returns the coordinate range that the data points in the specified key range (inKeyRange) span in the value axis dimension. For logarithmic plots, one can set inSignDomain to either QCP::sdNegative or QCP::sdPositive in order to restrict the returned range to that sign domain. E.g. when only negative range is wanted, set inSignDomain to QCP::sdNegative and all positive points will be ignored for range calculation. For no restriction, just set inSignDomain to QCP::sdBoth (default). foundRange is an output parameter that indicates whether a range could be found or not. If this is false, you shouldn't use the returned range (e.g. no points in data).

If inKeyRange has both lower and upper bound set to zero (is equal to QCPRange()), all data points are considered, without any restriction on the keys.

Note that foundRange is not the same as QCPRange::validRange, since the range returned by this function may have size zero (e.g. when there is only one data point). In this case foundRange would return true, but the returned range is not a valid range in terms of QCPRange::validRange.

See also
rescaleAxes, getKeyRange

Implements QCPAbstractPlottable.

§ dataPixelPosition()

QPointF QCPBars::dataPixelPosition ( int  index) const
virtual

Returns the pixel position on the widget surface at which the data point at the given index appears.

Usually this corresponds to the point of dataMainKey/dataMainValue, in pixel coordinates. However, depending on the plottable, this might be a different apparent position than just a coord-to-pixel transform of those values. For example, QCPBars apparent data values can be shifted depending on their stacking, bar grouping or configured base value.

Reimplemented from QCPAbstractPlottable1D< QCPBarsData >.

§ draw()

void QCPBars::draw ( QCPPainter painter)
protectedvirtual

This function draws the layerable with the specified painter. It is only called by QCustomPlot, if the layerable is visible (setVisible).

Before this function is called, the painter's antialiasing state is set via applyDefaultAntialiasingHint, see the documentation there. Further, the clipping rectangle was set to clipRect.

Implements QCPAbstractPlottable.

§ drawLegendIcon()

void QCPBars::drawLegendIcon ( QCPPainter painter,
const QRectF &  rect 
) const
protectedvirtual

called by QCPLegend::draw (via QCPPlottableLegendItem::draw) to create a graphical representation of this plottable inside rect, next to the plottable name.

The passed painter has its cliprect set to rect, so painting outside of rect won't appear outside the legend icon border.

Implements QCPAbstractPlottable.

§ getVisibleDataBounds()

void QCPBars::getVisibleDataBounds ( QCPBarsDataContainer::const_iterator &  begin,
QCPBarsDataContainer::const_iterator &  end 
) const
protected

called by draw to determine which data (key) range is visible at the current key axis range setting, so only that needs to be processed. It also takes into account the bar width.

begin returns an iterator to the lowest data point that needs to be taken into account when plotting. Note that in order to get a clean plot all the way to the edge of the axis rect, lower may still be just outside the visible range.

end returns an iterator one higher than the highest visible data point. Same as before, end may also lie just outside of the visible range.

if the plottable contains no data, both begin and end point to constEnd.

§ getBarRect()

QRectF QCPBars::getBarRect ( double  key,
double  value 
) const
protected

Returns the rect in pixel coordinates of a single bar with the specified key and value. The rect is shifted according to the bar stacking (see moveAbove) and base value (see setBaseValue), and to have non-overlapping border lines with the bars stacked below.

§ getPixelWidth()

void QCPBars::getPixelWidth ( double  key,
double &  lower,
double &  upper 
) const
protected

This function is used to determine the width of the bar at coordinate key, according to the specified width (setWidth) and width type (setWidthType).

The output parameters lower and upper return the number of pixels the bar extends to lower and higher keys, relative to the key coordinate (so with a non-reversed horizontal axis, lower is negative and upper positive).

§ getStackedBaseValue()

double QCPBars::getStackedBaseValue ( double  key,
bool  positive 
) const
protected

This function is called to find at which value to start drawing the base of a bar at key, when it is stacked on top of another QCPBars (e.g. with moveAbove).

positive and negative bars are separated per stack (positive are stacked above baseValue upwards, negative are stacked below baseValue downwards). This can be indicated with positive. So if the bar for which we need the base value is negative, set positive to false.

§ connectBars()

void QCPBars::connectBars ( QCPBars lower,
QCPBars upper 
)
staticprotected

Connects below and above to each other via their mBarAbove/mBarBelow properties. The bar(s) currently above lower and below upper will become disconnected to lower/upper.

If lower is zero, upper will be disconnected at the bottom. If upper is zero, lower will be disconnected at the top.


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