QLineF

The QLineF class provides a two-dimensional vector using floating point precision. More

Inheritance diagram of PySide2.QtCore.QLineF

Synopsis

Functions

Static functions

Detailed Description

A QLineF describes a finite length line (or line segment) on a two-dimensional surface. QLineF defines the start and end points of the line using floating point accuracy for coordinates. Use the toLine() function to retrieve an integer based copy of this line.

qline-point1

qline-coordinates2

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, respectively.

The line’s length can be retrieved using the length() function, and altered using the setLength() function. Similarly, angle() and setAngle() are respectively used for retrieving and altering the angle of the line. Use the isNull() function to determine whether the QLineF represents a valid line or a null line.

The intersects() function determines the IntersectionType for this line and a given line, while the angleTo() function returns the angle between the lines. In addition, the unitVector() function returns a line that has the same starting point as this line, but with a length of only 1, while the normalVector() function returns a line that is perpendicular to this line with the same starting point and length.

Finally, the line can be translated a given offset using the translate() function, and can be traversed using the pointAt() function.

Constraints

QLine is limited to the minimum and maximum values for the int type. Operations on a QLine that could potentially result in values outside this range will result in undefined behavior.

class QLineF

QLineF(line)

QLineF(QLineF)

QLineF(pt1, pt2)

QLineF(x1, y1, x2, y2)

param QLineF

QLineF

param y1

qreal

param line

QLine

param y2

qreal

param pt1

QPointF

param x1

qreal

param pt2

QPointF

param x2

qreal

Constructs a null line.

Construct a QLineF object from the given integer-based line .

See also

toLine()

Constructs a line object that represents the line between p1 and p2 .

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

PySide2.QtCore.QLineF.IntersectType
PySide2.QtCore.QLineF.__reduce__()
Return type

PyObject

PySide2.QtCore.QLineF.__repr__()
Return type

PyObject

PySide2.QtCore.QLineF.angle()
Return type

qreal

Returns the angle of the line in degrees.

The return value will be in the range of values from 0.0 up to but not including 360.0. The angles are measured counter-clockwise from a point on the x-axis to the right of the origin (x > 0).

See also

setAngle()

PySide2.QtCore.QLineF.angle(l)
Parameters

lQLineF

Return type

qreal

Note

This function is deprecated.

Returns the angle (in degrees) between this line and the given line , taking the direction of the lines into account. If the lines do not intersect within their range, it is the intersection point of the extended lines that serves as origin (see UnboundedIntersection ).

qlinef-angle-identicaldirection1

qlinef-angle-oppositedirection2

When the lines are parallel, this function returns 0 if they have the same direction; otherwise it returns 180.

See also

intersect()

PySide2.QtCore.QLineF.angleTo(l)
Parameters

lQLineF

Return type

qreal

Returns the angle (in degrees) from this line to the given line , taking the direction of the lines into account. If the lines do not intersect within their range, it is the intersection point of the extended lines that serves as origin (see UnboundedIntersection ).

The returned value represents the number of degrees you need to add to this line to make it have the same angle as the given line , going counter-clockwise.

See also

intersect()

PySide2.QtCore.QLineF.center()
Return type

QPointF

Returns the center point of this line. This is equivalent to 0.5 * p1() + 0.5 * p2() .

PySide2.QtCore.QLineF.dx()
Return type

qreal

Returns the horizontal component of the line’s vector.

See also

dy() pointAt()

PySide2.QtCore.QLineF.dy()
Return type

qreal

Returns the vertical component of the line’s vector.

See also

dx() pointAt()

static PySide2.QtCore.QLineF.fromPolar(length, angle)
Parameters
  • lengthqreal

  • angleqreal

Return type

QLineF

Returns a QLineF with the given length and angle .

The first point of the line will be on the origin.

Positive values for the angles mean counter-clockwise while negative values mean the clockwise direction. Zero degrees is at the 3 o’clock position.

PySide2.QtCore.QLineF.intersect(l)
Parameters

lQLineF

Return type

(intersectType, intersectionPoint)

Note

This function is deprecated.

Returns a value indicating whether or not this line intersects with the given line .

The actual intersection point is extracted to intersectionPoint (if the pointer is valid). If the lines are parallel, the intersection point is undefined.

PySide2.QtCore.QLineF.intersects(l, intersectionPoint)
Parameters
Return type

IntersectType

Returns a value indicating whether or not this line intersects with the given line .

The actual intersection point is extracted to intersectionPoint (if the pointer is valid). If the lines are parallel, the intersection point is undefined.

PySide2.QtCore.QLineF.isNull()
Return type

bool

Returns true if the line is not set up with valid start and end point; otherwise returns false .

PySide2.QtCore.QLineF.length()
Return type

qreal

Returns the length of the line.

See also

setLength()

PySide2.QtCore.QLineF.normalVector()
Return type

QLineF

Returns a line that is perpendicular to this line with the same starting point and length.

../../_images/qlinef-normalvector.png

See also

unitVector()

PySide2.QtCore.QLineF.__ne__(d)
Parameters

dQLineF

Return type

bool

Returns true if the given line is not the same as this line.

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

PySide2.QtCore.QLineF.__mul__(m)
Parameters

mQTransform

Return type

QLineF

PySide2.QtCore.QLineF.__mul__(m)
Parameters

mQMatrix

Return type

QLineF

PySide2.QtCore.QLineF.__eq__(d)
Parameters

dQLineF

Return type

bool

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.

PySide2.QtCore.QLineF.p1()
Return type

QPointF

Returns the line’s start point.

See also

setP1() x1() y1() p2()

PySide2.QtCore.QLineF.p2()
Return type

QPointF

Returns the line’s end point.

See also

setP2() x2() y2() p1()

PySide2.QtCore.QLineF.pointAt(t)
Parameters

tqreal

Return type

QPointF

Returns the point at the parameterized position specified by t . The function returns the line’s start point if t = 0, and its end point if t = 1.

See also

dx() dy()

PySide2.QtCore.QLineF.setAngle(angle)
Parameters

angleqreal

Sets the angle of the line to the given angle (in degrees). This will change the position of the second point of the line such that the line has the given angle.

Positive values for the angles mean counter-clockwise while negative values mean the clockwise direction. Zero degrees is at the 3 o’clock position.

See also

angle()

PySide2.QtCore.QLineF.setLength(len)
Parameters

lenqreal

Sets the length of the line to the given length . QLineF will move the end point - p2() - of the line to give the line its new length.

If the line is a null line, the length will remain zero regardless of the length specified.

See also

length() isNull()

PySide2.QtCore.QLineF.setLine(x1, y1, x2, y2)
Parameters
  • x1qreal

  • y1qreal

  • x2qreal

  • y2qreal

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

PySide2.QtCore.QLineF.setP1(p1)
Parameters

p1QPointF

Sets the starting point of this line to p1 .

See also

setP2() p1()

PySide2.QtCore.QLineF.setP2(p2)
Parameters

p2QPointF

Sets the end point of this line to p2 .

See also

setP1() p2()

PySide2.QtCore.QLineF.setPoints(p1, p2)
Parameters

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

PySide2.QtCore.QLineF.toLine()
Return type

QLine

Returns an integer based copy of this line.

Note that the returned line’s start and end points are rounded to the nearest integer.

See also

QLineF()

PySide2.QtCore.QLineF.toTuple()
Return type

PyObject

PySide2.QtCore.QLineF.translate(p)
Parameters

pQPointF

Translates this line by the given offset .

PySide2.QtCore.QLineF.translate(dx, dy)
Parameters
  • dxqreal

  • dyqreal

This is an overloaded function.

Translates this line the distance specified by dx and dy .

PySide2.QtCore.QLineF.translated(p)
Parameters

pQPointF

Return type

QLineF

Returns this line translated by the given offset .

PySide2.QtCore.QLineF.translated(dx, dy)
Parameters
  • dxqreal

  • dyqreal

Return type

QLineF

This is an overloaded function.

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

PySide2.QtCore.QLineF.unitVector()
Return type

QLineF

Returns the unit vector for this line, i.e a line starting at the same point as this line with a length of 1.0.

See also

normalVector()

PySide2.QtCore.QLineF.x1()
Return type

qreal

Returns the x-coordinate of the line’s start point.

See also

p1()

PySide2.QtCore.QLineF.x2()
Return type

qreal

Returns the x-coordinate of the line’s end point.

See also

p2()

PySide2.QtCore.QLineF.y1()
Return type

qreal

Returns the y-coordinate of the line’s start point.

See also

p1()

PySide2.QtCore.QLineF.y2()
Return type

qreal

Returns the y-coordinate of the line’s end point.

See also

p2()