QLine class provides a two-dimensional vector using integer precision. 更多...
| 头： | #include <QLine> |
| qmake: | QT += core |
| 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 ) |
| void | translate (const QPoint & offset ) |
| void | translate (int dx , int dy ) |
| QLine | translated (const QPoint & offset ) const |
| QLine | translated (int dx , int dy ) const |
| bool | operator!= (const QLine & line ) const |
| bool | operator== (const QLine & line ) const |
| QDataStream & | operator<< (QDataStream & stream , const QLine & line ) |
| QDataStream & | operator>> (QDataStream & stream , QLine & line ) |
QLine class provides a two-dimensional vector using integer precision.
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.
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The positions of the line's start and end points can be retrieved using the p1 (), x1 (), y1 (), p2 (), x2 ()，和 y2 () 函数。 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 () 函数。
另请参阅 QLineF , QPolygon ，和 QRect .
构造 null 线条。
构造的线条对象表示线条介于 p1 and p2 .
Constructs a line object that represents the line between ( x1 , y1 ) 和 ( x2 , y2 ).
返回线条的起始点。
另请参阅 setP1 (), x1 (), y1 ()，和 p2 ().
返回线条的结束点。
另请参阅 setP2 (), x2 (), y2 ()，和 p1 ().
返回线条起始点的 X 坐标。
另请参阅 p1 ().
返回线条结束点的 X 坐标。
另请参阅 p2 ().
返回线条起始点的 Y 坐标。
另请参阅 p1 ().
返回线条结束点的 Y 坐标。
另请参阅 p2 ().
Returns the center point of this line. This is equivalent to ( p1 () + p2 ()) / 2, except it will never overflow.
该函数在 Qt 5.8 引入。
Returns the horizontal component of the line's vector.
另请参阅 dy ().
Returns the vertical component of the line's vector.
另请参阅 dx ().
返回
true
if the line is not set up with valid start and end point; otherwise returns
false
.
Sets the starting point of this line to p1 .
该函数在 Qt 4.4 引入。
Sets the end point of this line to p2 .
该函数在 Qt 4.4 引入。
Sets this line to the start in x1 , y1 and end in x2 , y2 .
该函数在 Qt 4.4 引入。
另请参阅 setP1 (), setP2 (), p1 ()，和 p2 ().
Sets the start point of this line to p1 and the end point of this line to p2 .
该函数在 Qt 4.4 引入。
另请参阅 setP1 (), setP2 (), p1 ()，和 p2 ().
Translates this line by the given offset .
这是重载函数。
Translates this line the distance specified by dx and dy .
Returns this line translated by the given offset .
该函数在 Qt 4.4 引入。
这是重载函数。
Returns this line translated the distance specified by dx and dy .
该函数在 Qt 4.4 引入。
返回
true
若给定
line
is not the same as
this
line.
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.
返回
true
若给定
line
如同
this
line.
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.
写入给定 line 到给定 stream 并返回流引用。
另请参阅 序列化 Qt 数据类型 .
Reads a line from the given stream 进给定 line 并返回流引用。
另请参阅 序列化 Qt 数据类型 .
