QLine 類

QLine 類提供使用整數精度的 2D 嚮量。 更多...

頭：	#include <QLine>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Core) target_link_libraries(mytarget PRIVATE Qt6::Core)
qmake:	QT += core

• 所有成員列錶，包括繼承成員
• QLine is part of 描繪類 .

此類 相等可比較 .

此類 相等可比較 with QLineF .

公共函數

	QLine ()
	QLine (const QPoint & p1 , const QPoint & p2 )
	QLine (int x1 , int y1 , int x2 , int y2 )
QPoint	p1 () const
QPoint	p2 () const
int	x1 () const
int	x2 () const
int	y1 () const
int	y2 () const
QPoint	center () const
int	dx () const
int	dy () const
bool	isNull () const
void	setP1 (const QPoint & p1 )
void	setP2 (const QPoint & p2 )
void	setLine (int x1 , int y1 , int x2 , int y2 )
void	setPoints (const QPoint & p1 , const QPoint & p2 )
(從 6.4 起) QLineF	toLineF () const
void	translate (const QPoint & offset )
void	translate (int dx , int dy )
QLine	translated (const QPoint & offset ) const
QLine	translated (int dx , int dy ) const

相關非成員

bool	operator!= (const QLine & lhs , const QLine & rhs )
QDataStream &	operator<< (QDataStream & stream , const QLine & line )
bool	operator== (const QLine & lhs , const QLine & rhs )
QDataStream &	operator>> (QDataStream & stream , QLine & line )

詳細描述

A QLine describes a finite length line (or a line segment) on a two-dimensional surface. The start and end points of the line are specified using integer point accuracy for coordinates. Use the QLineF constructor to retrieve a floating point copy.

The positions of the line's start and end points can be retrieved using the p1 (), x1 (), y1 (), p2 (), x2 ()，和 y2 () 函數。 dx () 和 dy () functions return the horizontal and vertical components of the line. Use isNull () to determine whether the QLine represents a valid line or a null line.

Finally, the line can be translated a given offset using the translate () 函數。

另請參閱 QLineF , QPolygon ，和 QRect .

成員函數文檔編製

[constexpr] QLine:: QLine ()

構造 null 綫條。

[constexpr] QLine:: QLine (const QPoint & p1 , const QPoint & p2 )

構造的綫條對象錶示綫條介於 p1 and p2 .

[constexpr] QLine:: QLine ( int x1 , int y1 , int x2 , int y2 )

Constructs a line object that represents the line between ( x1 , y1 ) 和 ( x2 , y2 ).

[constexpr] QPoint QLine:: p1 () const

返迴綫條的起始點。

另請參閱 setP1 (), x1 (), y1 ()，和 p2 ().

[constexpr] QPoint QLine:: p2 () const

返迴綫的終點。

另請參閱 setP2 (), x2 (), y2 ()，和 p1 ().

[constexpr] int QLine:: x1 () const

返迴綫條起始點的 X 坐標。

另請參閱 p1 ().

[constexpr] int QLine:: x2 () const

返迴綫終點的 X 坐標。

另請參閱 p2 ().

[constexpr] int QLine:: y1 () const

返迴綫條起始點的 Y 坐標。

另請參閱 p1 ().

[constexpr] int QLine:: y2 () const

返迴綫終點的 Y 坐標。

另請參閱 p2 ().

[constexpr] QPoint QLine:: center () const

Returns the center point of this line. This is equivalent to ( p1 () + p2 ()) / 2, except it will never overflow.

[constexpr] int QLine:: dx () const

Returns the horizontal component of the line's vector.

另請參閱 dy ().

[constexpr] int QLine:: dy () const

Returns the vertical component of the line's vector.

另請參閱 dx ().

[constexpr] bool QLine:: isNull () const

返迴 true if the line does not have distinct start and end points; otherwise returns false .

void QLine:: setP1 (const QPoint & p1 )

Sets the starting point of this line to p1 .

另請參閱 setP2 () 和 p1 ().

void QLine:: setP2 (const QPoint & p2 )

Sets the end point of this line to p2 .

另請參閱 setP1 () 和 p2 ().

void QLine:: setLine ( int x1 , int y1 , int x2 , int y2 )

Sets this line to the start in x1 , y1 and end in x2 , y2 .

另請參閱 setP1 (), setP2 (), p1 ()，和 p2 ().

void QLine:: setPoints (const QPoint & p1 , const QPoint & p2 )

Sets the start point of this line to p1 and the end point of this line to p2 .

另請參閱 setP1 (), setP2 (), p1 ()，和 p2 ().

[constexpr noexcept, since 6.4] QLineF QLine:: toLineF () const

Returns this line as a line with floating point accuracy.

該函數在 Qt 6.4 引入。

另請參閱 QLineF::toLine ().

void QLine:: translate (const QPoint & offset )

Translates this line by the given offset .

void QLine:: translate ( int dx , int dy )

這是重載函數。

Translates this line the distance specified by dx and dy .

[constexpr] QLine QLine:: translated (const QPoint & offset ) const

Returns this line translated by the given offset .

[constexpr] QLine QLine:: translated ( int dx , int dy ) const

這是重載函數。

Returns this line translated the distance specified by dx and dy .

相關非成員

[constexpr noexcept] bool operator!= (const QLine & lhs , const QLine & rhs )

返迴 true if the line lhs is not the same as line rhs .

A line is different from another line if any of their start or end points differ, or the internal order of the points is different.

QDataStream & operator<< ( QDataStream & stream , const QLine & line )

寫入給定 line 到給定 stream 並返迴流引用。

另請參閱 序列化 Qt 數據類型 .

[constexpr noexcept] bool operator== (const QLine & lhs , const QLine & rhs )

返迴 true if the line lhs is the same as line rhs .

A line is identical to another line if the start and end points are identical, and the internal order of the points is the same.

QDataStream & operator>> ( QDataStream & stream , QLine & line )

Reads a line from the given stream 進給定 line 並返迴流引用。

另請參閱 序列化 Qt 數據類型 .

內容

1. 公共函數

2. 相關非成員

3. 詳細描述