QLine Class▲
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Header: QLine
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CMake:
find_package(Qt6 REQUIRED COMPONENTS Core)
target_link_libraries(mytarget PRIVATE Qt6::Core)
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qmake: QT += core
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Group: QLine is part of painting
Detailed Description▲
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(), and y2() functions. The dx() and 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() function.
See Also▲
Member Function Documentation▲
[constexpr] QLine::QLine()▲
Constructs a null line.
[constexpr] QLine::QLine(const QPoint &p1, const QPoint &p2)▲
Constructs a line object that represents the line between 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) and (x2, y2).
[constexpr] QPoint QLine::p1() const▲
[constexpr] QPoint QLine::p2() const▲
[constexpr] int QLine::x1() const▲
[constexpr] int QLine::x2() const▲
[constexpr] int QLine::y1() const▲
[constexpr] int QLine::y2() const▲
[constexpr, since 5.8] QPoint QLine::center() const▲
Returns the center point of this line. This is equivalent to (p1() + p2()) / 2, except it will never overflow.
This function was introduced in Qt 5.8.
[constexpr] int QLine::dx() const▲
[constexpr] int QLine::dy() const▲
[constexpr] bool QLine::isNull() const▲
Returns true if the line does not have distinct start and end points; otherwise returns false.
void QLine::setP1(const QPoint &p1)▲
void QLine::setP2(const QPoint &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.
See Also▲
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.
See Also▲
[constexpr, since 6.4] QLineF QLine::toLineF() const▲
Returns this line as a line with floating point accuracy.
This function was introduced in Qt 6.4.
See Also▲
See also QLineF::toLine()
void QLine::translate(const QPoint &offset)▲
Translates this line by the given offset.
void QLine::translate(int dx, int dy)▲
This is an overloaded function.
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▲
This is an overloaded function.
Returns this line translated the distance specified by dx and dy.
[constexpr] bool QLine::operator!=(const QLine &line) const▲
Returns true if the given 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.
[constexpr] bool QLine::operator==(const QLine &line) const▲
Returns true if the given line is the same as 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.
Related Non-Members▲
QDataStream &operator<<(QDataStream &stream, const QLine &line)▲
Writes the given line to the given stream and returns a reference to the stream.
See Also▲
See also Serializing Qt Data Types
QDataStream &operator>>(QDataStream &stream, QLine &line)▲
Reads a line from the given stream into the given line and returns a reference to the stream.
See Also▲
See also Serializing Qt Data Types