---
name: "QwtPlotSeriesItem"
section: "3"
platform: "linux"
package: "libqwt-doc"
version: "6.1.4-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/QwtPlotSeriesItem"
---

# QwtPlotSeriesItem(3)

Base class for plot items representing a series of samples.

## NAME

QwtPlotSeriesItem - Base class for plot items representing a series of samples.

## SYNOPSIS

`#include <qwt_plot_seriesitem.h>`

Inherits **QwtPlotItem**, and **QwtAbstractSeriesStore**.

Inherited by **QwtPlotAbstractBarChart**, **QwtPlotCurve**, **QwtPlotHistogram**, **QwtPlotIntervalCurve**, **QwtPlotSpectroCurve**, and **QwtPlotTradingCurve**.

### Public Member Functions

**QwtPlotSeriesItem** (const QString &**title**=QString())\
 **QwtPlotSeriesItem** (const **QwtText** &**title**)\
 virtual **~QwtPlotSeriesItem** ()\
 Destructor.  void **setOrientation** (Qt::Orientation)\
 Qt::Orientation **orientation** () const\
 virtual void **draw** (QPainter \*, const **QwtScaleMap** &xMap, const **QwtScaleMap** &yMap, const QRectF &) const\
 Draw the complete series.  virtual void **drawSeries** (QPainter \*painter, const **QwtScaleMap** &xMap, const **QwtScaleMap** &yMap, const QRectF &canvasRect, int from, int to) const =0\
 virtual QRectF **boundingRect** () const\
 virtual void **updateScaleDiv** (const **QwtScaleDiv** &, const **QwtScaleDiv** &)\
 Update the item to changes of the axes scale division.

### Protected Member Functions

virtual void **dataChanged** ()\
 **dataChanged()** indicates, that the series has been changed.

### Additional Inherited Members

## Detailed Description

Base class for plot items representing a series of samples.

## Constructor & Destructor Documentation

### QwtPlotSeriesItem::QwtPlotSeriesItem (const QString & title = `QString()`)` [explicit]`

Constructor

**Parameters:**

*title* Title of the curve

### QwtPlotSeriesItem::QwtPlotSeriesItem (const QwtText & title)` [explicit]`

Constructor

**Parameters:**

*title* Title of the curve

## Member Function Documentation

### QRectF QwtPlotSeriesItem::boundingRect () const` [virtual]`

**Returns:**

An invalid bounding rect: QRectF(1.0, 1.0, -2.0, -2.0)

**Note:**

A width or height \< 0.0 is ignored by the autoscaler

Reimplemented from **QwtPlotItem**.

Reimplemented in **QwtPlotTradingCurve**, **QwtPlotIntervalCurve**, **QwtPlotHistogram**, **QwtPlotBarChart**, and **QwtPlotMultiBarChart**.

### void QwtPlotSeriesItem::draw (QPainter \* painter, const QwtScaleMap & xMap, const QwtScaleMap & yMap, const QRectF & canvasRect) const` [virtual]`

Draw the complete series.

**Parameters:**

*painter* Painter \
 *xMap* Maps x-values into pixel coordinates. \
 *yMap* Maps y-values into pixel coordinates. \
 *canvasRect* Contents rectangle of the canvas

Implements **QwtPlotItem**.

### virtual void QwtPlotSeriesItem::drawSeries (QPainter \* painter, const QwtScaleMap & xMap, const QwtScaleMap & yMap, const QRectF & canvasRect, int from, int to) const` [pure virtual]`

Draw a subset of the samples

**Parameters:**

*painter* Painter \
 *xMap* Maps x-values into pixel coordinates. \
 *yMap* Maps y-values into pixel coordinates. \
 *canvasRect* Contents rectangle of the canvas \
 *from* Index of the first point to be painted \
 *to* Index of the last point to be painted. If to \< 0 the curve will be painted to its last point.

Implemented in **QwtPlotCurve**, **QwtPlotTradingCurve**, **QwtPlotIntervalCurve**, **QwtPlotHistogram**, **QwtPlotBarChart**, **QwtPlotMultiBarChart**, and **QwtPlotSpectroCurve**.

### Qt::Orientation QwtPlotSeriesItem::orientation () const

**Returns:**

Orientation of the plot item

**See also:**

**setOrientation()**

### void QwtPlotSeriesItem::setOrientation (Qt::Orientation orientation)

Set the orientation of the item.

The **orientation()** might be used in specific way by a plot item. F.e. a **QwtPlotCurve** uses it to identify how to display the curve int **QwtPlotCurve::Steps** or **QwtPlotCurve::Sticks** style.

**See also:**

**orientation()**

### void QwtPlotSeriesItem::updateScaleDiv (const QwtScaleDiv & xScaleDiv, const QwtScaleDiv & yScaleDiv)` [virtual]`

Update the item to changes of the axes scale division. Update the item, when the axes of plot have changed. The default implementation does nothing, but items that depend on the scale division (like **QwtPlotGrid()**) have to reimplement **updateScaleDiv()**

**updateScaleDiv()** is only called when the ScaleInterest interest is enabled. The default implementation does nothing.

**Parameters:**

*xScaleDiv* Scale division of the x-axis \
 *yScaleDiv* Scale division of the y-axis

**See also:**

**QwtPlot::updateAxes()**, **ScaleInterest**

Reimplemented from **QwtPlotItem**.

## Author

Generated automatically by Doxygen for Qwt User's Guide from the source code.