- Qt 6.9
- Qt Widgets
- C++ Classes
- QGraphicsLineItem
- Qt 6.9.2 Reference Documentation

# QGraphicsLineItem Class

The QGraphicsLineItem class provides a line item that you can add to a QGraphicsScene. More...

Header: | `#include <QGraphicsLineItem>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS Widgets)` `target_link_libraries(mytarget PRIVATE Qt6::Widgets)`
qmake: | `QT += widgets`
Inherits: | QGraphicsItem

- List of all members, including inherited members

## Public Types

enum | anonymous { Type }

## Public Functions

| QGraphicsLineItem(QGraphicsItem *parent = nullptr)
| QGraphicsLineItem(const QLineF &line, QGraphicsItem *parent = nullptr)
| QGraphicsLineItem(qreal x1, qreal y1, qreal x2, qreal y2, QGraphicsItem *parent = nullptr)
virtual | ~QGraphicsLineItem()
QLineF | line() const
QPen | pen() const
void | setLine(const QLineF &line)
void | setLine(qreal x1, qreal y1, qreal x2, qreal y2)
void | setPen(const QPen &pen)

## Reimplemented Public Functions

virtual QRectF | boundingRect() const override
virtual bool | contains(const QPointF &point) const override
virtual bool | isObscuredBy(const QGraphicsItem *item) const override
virtual QPainterPath | opaqueArea() const override
virtual void | paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = nullptr) override
virtual QPainterPath | shape() const override
virtual int | type() const override

## Detailed Description

To set the item's line, pass a QLineF to QGraphicsLineItem's constructor, or call the setLine() function. The line() function returns the current line. By default the line is black with a width of 0, but you can change this by calling setPen().

QGraphicsLineItem uses the line and the pen width to provide a reasonable implementation of boundingRect(), shape(), and contains(). The paint() function draws the line using the item's associated pen.

See also QGraphicsPathItem, QGraphicsRectItem, QGraphicsEllipseItem, QGraphicsTextItem, QGraphicsPolygonItem, QGraphicsPixmapItem, and Graphics View Framework.

## Member Type Documentation

### enum QGraphicsLineItem::anonymous

The value returned by the virtual type() function.

Constant | Value | Description
--- | --- | ---
`QGraphicsLineItem::Type` | `6` | A graphics line item

## Member Function Documentation

### `[explicit]` QGraphicsLineItem::QGraphicsLineItem(QGraphicsItem *parent = nullptr)

Constructs a QGraphicsLineItem. parent is passed to QGraphicsItem's constructor.

See also QGraphicsScene::addItem().

### `[explicit]` QGraphicsLineItem::QGraphicsLineItem(const QLineF &line, QGraphicsItem *parent = nullptr)

Constructs a QGraphicsLineItem, using line as the default line. parent is passed to QGraphicsItem's constructor.

See also QGraphicsScene::addItem().

### `[explicit]` QGraphicsLineItem::QGraphicsLineItem(qreal x1, qreal y1, qreal x2, qreal y2, QGraphicsItem *parent = nullptr)

Constructs a QGraphicsLineItem, using the line between (x1, y1) and (x2, y2) as the default line. parent is passed to QGraphicsItem's constructor.

See also QGraphicsScene::addItem().

### `[virtual noexcept]` QGraphicsLineItem::~QGraphicsLineItem()

Destroys the QGraphicsLineItem.

### `[override virtual]` QRectF QGraphicsLineItem::boundingRect() const

Reimplements: QGraphicsItem::boundingRect() const.

### `[override virtual]` bool QGraphicsLineItem::contains(const QPointF &point) const

Reimplements: QGraphicsItem::contains(const QPointF &point) const.

### `[override virtual]` bool QGraphicsLineItem::isObscuredBy(const QGraphicsItem *item) const

Reimplements: QGraphicsItem::isObscuredBy(const QGraphicsItem *item) const.

### QLineF QGraphicsLineItem::line() const

Returns the item's line, or a null line if no line has been set.

See also setLine().

### `[override virtual]` QPainterPath QGraphicsLineItem::opaqueArea() const

Reimplements: QGraphicsItem::opaqueArea() const.

### `[override virtual]` void QGraphicsLineItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = nullptr)

Reimplements: QGraphicsItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget).

### QPen QGraphicsLineItem::pen() const

Returns the item's pen, or a black solid 0-width pen if no pen has been set.

See also setPen().

### void QGraphicsLineItem::setLine(const QLineF &line)

Sets the item's line to be the given line.

See also line().

### void QGraphicsLineItem::setLine(qreal x1, qreal y1, qreal x2, qreal y2)

Sets the item's line to be the line between (x1, y1) and (x2, y2).

This is the same as calling `setLine(QLineF(x1, y1, x2, y2))`.

This is an overloaded function.

### void QGraphicsLineItem::setPen(const QPen &pen)

Sets the item's pen to pen. If no pen is set, the line will be painted using a black solid 0-width pen.

See also pen().

### `[override virtual]` QPainterPath QGraphicsLineItem::shape() const

Reimplements: QGraphicsItem::shape() const.

### `[override virtual]` int QGraphicsLineItem::type() const

Reimplements: QGraphicsItem::type() const.