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The QLineF class provides a two-dimensional vector that uses floating point coordinates for accuracy. More...
#include <QLineF>
The QLineF class provides a two-dimensional vector that uses floating point coordinates for accuracy.
A QLineF describes a finite length line on a two-dimensional surface. The start and end points of the line are specified using floating point coordinates for accuracy.
Use isNull() to determine whether the QLineF represents a valid line or a null line.
The positions of the line's end points can be found with the startX(), startY(), endX(), and endY() functions. The horizontal and vertical components of the line are returned by the vx() and vy() functions.
Convenience functions are provided for finding the lines's length(), the unitVector() along the line, whether two lines intersect(), and the angle() between two lines. The line's length can be changed using setLength().
Vector addition of two lines is supported through the use of the += operator.
The line can be translated along the length of another line with the moveBy() function, and can be traversed using a parameter with the pointAt() function.
See also QPointF, QSizeF, and QRectF.
QLineF::NoIntersection | Indicates that the lines do not intersect; i.e. they are parallel. |
QLineF::UnboundedIntersection | The two lines intersect, but not within the range defined by their lengths. This will be the case if the lines are not parallel.![]() |
QLineF::BoundedIntersection | The two lines intersect with each other within the start and end points of each line.![]() |
Constructs a null line.
Constructs a line object that represents the line between pt1 and pt2.
Constructs a line object that represents the line between (x1, y1) and (x2, y2).
Returns the smallest angle between the given line and this line, not taking into account whether the lines intersect or not. The angle is specified in degrees.
Returns the line's end point.
Returns the x-coordinate of the line's end point.
Returns the y-coordinate of the line's end point.
Returns a value indicating whether or not this line intersects the other line. By passing a valid object as intersectionPoint, it is possible to get the actual intersection point. The intersection point is undefined if the lines are parallel.
Returns true if the line is not set up with valid start and end point; otherwise returns false.
Returns the length of the line.
See also setLength().
Translates this line by the vector specified by the line given.
Returns a line that is perpendicular to this line with the same starting point and length.
Returns the point at the parameterized position t, where the start and end point are defined to be at positions t=0 and t=1.
Sets the length of the line.
See also length().
Returns the line's start point.
Returns the x-coordinate of the line's start point.
Returns the y-coordinate of the line's start point.
Returns a normalized version of this line, starting at the same point as this line. A normalized line is a line of unit length (length() is equal to 1.0).
Returns the horizontal component of the line's vector.
Returns the vertical component of the line's vector.
Performs a vector addition of this line with the other line given.
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