# QwtPlotMarker Class Reference

A class for drawing markers. More...

`#include <qwt_plot_marker.h>`

Inheritance diagram for QwtPlotMarker:
[legend]

List of all members.

## Public Types
enum | LineStyle { NoLine, HLine, VLine, Cross }
## Public Member Functions
| QwtPlotMarker ()
virtual | ~QwtPlotMarker ()
virtual int | rtti () const
double | xValue () const
double | yValue () const
QwtDoublePoint | value () const
void | setXValue (double)
void | setYValue (double)
void | setValue (double, double)
void | setValue (const QwtDoublePoint &)
void | setLineStyle (LineStyle st)
LineStyle | lineStyle () const
void | setLinePen (const QPen &p)
const QPen & | linePen () const
void | setSymbol (const QwtSymbol &s)
const QwtSymbol & | symbol () const
void | setLabel (const QwtText &)
QwtText | label () const
void | setLabelAlignment (Qt::Alignment)
Qt::Alignment | labelAlignment () const
void | setLabelOrientation (Qt::Orientation)
Qt::Orientation | labelOrientation () const
void | setSpacing (int)
int | spacing () const
virtual void | draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &) const
virtual QwtDoubleRect | boundingRect () const
## Protected Member Functions
void | drawAt (QPainter *, const QRect &, const QPoint &) const

## Detailed Description

A class for drawing markers.

A marker can be a horizontal line, a vertical line, a symbol, a label or any combination of them, which can be drawn around a center point inside a bounding rectangle.

The QwtPlotMarker::setSymbol() member assigns a symbol to the marker. The symbol is drawn at the specified point.

With QwtPlotMarker::setLabel(), a label can be assigned to the marker. The QwtPlotMarker::setLabelAlignment() member specifies where the label is drawn. All the Align*-constants in Qt::AlignmentFlags (see Qt documentation) are valid. The interpretation of the alignment depends on the marker's line style. The alignment refers to the center point of the marker, which means, for example, that the label would be printed left above the center point if the alignment was set to AlignLeft|AlignTop.

## Member Enumeration Documentation

enum QwtPlotMarker::LineStyle

Line styles.

See also:
  setLineStyle(), lineStyle()

## Constructor & Destructor Documentation

QwtPlotMarker::QwtPlotMarker | ( |  | ) | `[explicit]`

Sets alignment to Qt::AlignCenter, and style to NoLine.

QwtPlotMarker::~QwtPlotMarker | ( |  | ) | `[virtual]`

Destructor.

## Member Function Documentation

QwtDoubleRect QwtPlotMarker::boundingRect | ( |  | ) | const`[virtual]`

Returns:
  An invalid bounding rect: QwtDoubleRect(1.0, 1.0, -2.0, -2.0)

Reimplemented from QwtPlotItem.

void QwtPlotMarker::draw | ( | QPainter * | painter,
|  | const QwtScaleMap & | xMap,
|  | const QwtScaleMap & | yMap,
|  | const QRect & | canvasRect |
| ) |  |  | const`[virtual]`

Draw the marker

Parameters:

  | painter | Painter
  | xMap | x Scale Map
  | yMap | y Scale Map
  | canvasRect | Contents rect of the canvas in painter coordinates

Implements QwtPlotItem.

void QwtPlotMarker::drawAt | ( | QPainter * | painter,
|  | const QRect & | canvasRect,
|  | const QPoint & | pos |
| ) |  |  | const`[protected]`

Draw the marker at a specific position

Parameters:

  | painter | Painter
  | canvasRect | Contents rect of the canvas in painter coordinates
  | pos | Position of the marker in painter coordinates

QwtText QwtPlotMarker::label | ( |  | ) | const

Returns:
  the label

See also:
  setLabel()

Qt::Alignment QwtPlotMarker::labelAlignment | ( |  | ) | const

Returns:
  the label alignment

See also:
  setLabelAlignment(), setLabelOrientation()

Qt::Orientation QwtPlotMarker::labelOrientation | ( |  | ) | const

Returns:
  the label orientation

See also:
  setLabelOrientation(), labelAlignment()

const QPen & QwtPlotMarker::linePen | ( |  | ) | const

Returns:
  the line pen

See also:
  setLinePen()

QwtPlotMarker::LineStyle QwtPlotMarker::lineStyle | ( |  | ) | const

Returns:
  the line style

See also:
  For a description of line styles, see QwtPlotMarker::setLineStyle()

int QwtPlotMarker::rtti | ( |  | ) | const`[virtual]`

Returns:
  QwtPlotItem::Rtti_PlotMarker

Reimplemented from QwtPlotItem.

void QwtPlotMarker::setLabel | ( | const QwtText & | label | ) |

Set the label.

Parameters:

  | label | label text

See also:
  label()

void QwtPlotMarker::setLabelAlignment | ( | Qt::Alignment | align | ) |

Set the alignment of the label.

In case of QwtPlotMarker::HLine the alignment is relative to the y position of the marker, but the horizontal flags correspond to the canvas rectangle. In case of QwtPlotMarker::VLine the alignment is relative to the x position of the marker, but the vertical flags correspond to the canvas rectangle.

In all other styles the alignment is relative to the marker's position.

Parameters:

  | align | Alignment. A combination of AlignTop, AlignBottom, AlignLeft, AlignRight, AlignCenter, AlgnHCenter, AlignVCenter.

See also:
  labelAlignment(), labelOrientation()

void QwtPlotMarker::setLabelOrientation | ( | Qt::Orientation | orientation | ) |

Set the orientation of the label.

When orientation is Qt::Vertical the label is rotated by 90.0 degrees ( from bottom to top ).

Parameters:

  | orientation | Orientation of the label

See also:
  labelOrientation(), setLabelAlignment()

void QwtPlotMarker::setLinePen | ( | const QPen & | pen | ) |

Specify a pen for the line.

The width of non cosmetic pens is scaled according to the resolution of the paint device.

Parameters:

  | pen | New pen

See also:
  linePen(), QwtPainter::scaledPen()

void QwtPlotMarker::setLineStyle | ( | QwtPlotMarker::LineStyle | st | ) |

Set the line style.

Parameters:

  | st | Line style. Can be one of QwtPlotMarker::NoLine, HLine, VLine or Cross

See also:
  lineStyle()

void QwtPlotMarker::setSpacing | ( | int | spacing | ) |

Set the spacing.

When the label is not centered on the marker position, the spacing is the distance between the position and the label.

Parameters:

  | spacing | Spacing

See also:
  spacing(), setLabelAlignment()

void QwtPlotMarker::setSymbol | ( | const QwtSymbol & | s | ) |

Assign a symbol.

Parameters:

  | s | New symbol

See also:
  symbol()

void QwtPlotMarker::setValue | ( | const QwtDoublePoint & | pos | ) |

Set Value.

void QwtPlotMarker::setValue | ( | double | x,
|  | double | y |
| ) |  |  |

Set Value.

void QwtPlotMarker::setXValue | ( | double | x | ) |

Set X Value.

void QwtPlotMarker::setYValue | ( | double | y | ) |

Set Y Value.

int QwtPlotMarker::spacing | ( |  | ) | const

Returns:
  the spacing

See also:
  setSpacing()

const QwtSymbol & QwtPlotMarker::symbol | ( |  | ) | const

Returns:
  the symbol

See also:
  setSymbol(), QwtSymbol

QwtDoublePoint QwtPlotMarker::value | ( |  | ) | const

Return Value.

double QwtPlotMarker::xValue | ( |  | ) | const

Return x Value.

double QwtPlotMarker::yValue | ( |  | ) | const

Return y Value.