内容

• 公共类型
• 公共函数
• 保护函数
• 重实现保护函数
• 详细描述

QRubberBand 类

QRubberBand class provides a rectangle or line that can indicate a selection or a boundary. 更多...

头：	#include <QRubberBand>
qmake:	QT += widgets
继承：	QWidget

• 所有成员列表，包括继承成员

公共类型

enum	Shape { Line, Rectangle }

公共函数

	QRubberBand (Shape s , QWidget * p = Q_NULLPTR)
	~QRubberBand ()
void	move (int x , int y )
void	move (const QPoint & p )
void	resize (int width , int height )
void	resize (const QSize & size )
void	setGeometry (const QRect & rect )
void	setGeometry (int x , int y , int width , int height )
形状	shape () const

• 214 公共函数继承自 QWidget
• 32 公共函数继承自 QObject
• 14 公共函数继承自 QPaintDevice

保护函数

void	initStyleOption (QStyleOptionRubberBand * option ) const

重实现保护函数

virtual void	changeEvent (QEvent * e )
virtual bool	event (QEvent * e )
virtual void	moveEvent ( QMoveEvent * )
virtual void	paintEvent ( QPaintEvent * )
virtual void	resizeEvent ( QResizeEvent * )
virtual void	showEvent (QShowEvent * e )

• 35 保护函数继承自 QWidget
• 9 保护函数继承自 QObject
• 1 保护函数继承自 QPaintDevice

额外继承成员

• 59 特性继承自 QWidget
• 1 特性继承自 QObject
• 19 公共槽继承自 QWidget
• 1 公共槽继承自 QObject
• 3 信号继承自 QWidget
• 2 信号继承自 QObject
• 5 静态公共成员继承自 QWidget
• 11 静态公共成员继承自 QObject
• 1 保护槽继承自 QWidget

详细描述

QRubberBand class provides a rectangle or line that can indicate a selection or a boundary.

橡皮筋经常用于展示新的边界区域 (如在 QSplitter 或 QDockWidget that is undocking). Historically this has been implemented using a QPainter and XOR, but this approach doesn't always work properly since rendering can happen in the window below the rubber band, but before the rubber band has been "erased".

You can create a QRubberBand whenever you need to render a rubber band around a given area (or to represent a single line), then call setGeometry (), move () 或 resize () to position and size it. A common pattern is to do this in conjunction with mouse events. For example:

void Widget::mousePressEvent(QMouseEvent *event)
{
    origin = event->pos();
    if (!rubberBand)
        rubberBand = new QRubberBand(QRubberBand::Rectangle, this);
    rubberBand->setGeometry(QRect(origin, QSize()));
    rubberBand->show();
}
void Widget::mouseMoveEvent(QMouseEvent *event)
{
    rubberBand->setGeometry(QRect(origin, event->pos()).normalized());
}
void Widget::mouseReleaseEvent(QMouseEvent *event)
{
    rubberBand->hide();
    // determine selection, for example using QRect::intersects()
    // and QRect::contains().
}
					

If you pass a parent to QRubberBand 's constructor, the rubber band will display only inside its parent, but stays on top of other child widgets. If no parent is passed, QRubberBand will act as a top-level widget.

调用 show () to make the rubber band visible; also when the rubber band is not a top-level. Hiding or destroying the widget will make the rubber band disappear. The rubber band can be a Rectangle 或 Line (vertical or horizontal), depending on the shape () it was given when constructed.

成员类型文档编制

enum QRubberBand:: Shape

This enum specifies what shape a QRubberBand should have. This is a drawing hint that is passed down to the style system, and can be interpreted by each QStyle .

常量	值	描述
QRubberBand::Line	0	A QRubberBand can represent a vertical or horizontal line. Geometry is still given in rect () and the line will fill the given geometry on most styles.
QRubberBand::Rectangle	1	A QRubberBand can represent a rectangle. Some styles will interpret this as a filled (often semi-transparent) rectangle, or a rectangular outline.

成员函数文档编制

QRubberBand:: QRubberBand ( Shape s , QWidget * p = Q_NULLPTR)

Constructs a rubber band of shape s ，采用父级 p .

By default a rectangular rubber band ( s is Rectangle ) will use a mask, so that a small border of the rectangle is all that is visible. Some styles (e.g., native macOS) will change this and call QWidget::setWindowOpacity () to make a semi-transparent filled selection rectangle.

QRubberBand:: ~QRubberBand ()

析构函数。

[virtual protected] void QRubberBand:: changeEvent ( QEvent * e )

重实现自 QWidget::changeEvent ().

[virtual protected] bool QRubberBand:: event ( QEvent * e )

重实现自 QObject::event ().

[protected] void QRubberBand:: initStyleOption ( QStyleOptionRubberBand * option ) const

初始化 option 采用值来自此 QRubberBand 。此方法对子类是有用的，当需要 QStyleOptionRubberBand ，但不希望自己填充所有信息。

另请参阅 QStyleOption::initFrom ().

void QRubberBand:: move ( int x , int y )

将橡皮筋移到点 ( x , y ).

另请参阅 resize ().

void QRubberBand:: move (const QPoint & p )

这是重载函数。

将橡皮筋移到点 p .

另请参阅 resize ().

[virtual protected] void QRubberBand:: moveEvent ( QMoveEvent * )

重实现自 QWidget::moveEvent ().

[virtual protected] void QRubberBand:: paintEvent ( QPaintEvent * )

重实现自 QWidget::paintEvent ().

void QRubberBand:: resize ( int width , int height )

Resizes the rubberband so that its width is width , and its height is height .

另请参阅 move ().

void QRubberBand:: resize (const QSize & size )

这是重载函数。

Resizes the rubberband so that its new size is size .

另请参阅 move ().

[virtual protected] void QRubberBand:: resizeEvent ( QResizeEvent * )

重实现自 QWidget::resizeEvent ().

void QRubberBand:: setGeometry (const QRect & rect )

Sets the geometry of the rubber band to rect , specified in the coordinate system of its parent widget.

另请参阅 QWidget::geometry .

void QRubberBand:: setGeometry ( int x , int y , int width , int height )

这是重载函数。

Sets the geometry of the rubberband to the rectangle whose top-left corner lies at the point ( x , y ), and with dimensions specified by width and height . The geometry is specified in the parent widget's coordinate system.

Shape QRubberBand:: shape () const

Returns the shape of this rubber band. The shape can only be set upon construction.

[virtual protected] void QRubberBand:: showEvent ( QShowEvent * e )

重实现自 QWidget::showEvent ().