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java.lang.Objectcom.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.gui.QLineF
public class QLineF
The QLineF
class provides a two-dimensional vector using floating point precision. 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.
![]() | ![]() |
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 intersect()
function determines the IntersectType
for this line and a given line, while the angle()
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.
QLine
, QPolygonF
, and QRectF
.
Nested Class Summary | |
---|---|
static class |
QLineF.IntersectType
Describes the intersection between two lines. |
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter |
---|
QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9 |
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
---|
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal |
Field Summary |
---|
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
---|
currentSender |
Constructor Summary | |
---|---|
QLineF()
Constructs a null line. |
|
QLineF(double x1,
double y1,
double x2,
double y2)
Constructs a line object that represents the line between (x1, y1) and (x2, y2). |
|
QLineF(QLine line)
Construct a QLineF object from the given integer-based line. |
|
QLineF(QPointF pt1,
QPointF pt2)
Constructs a line object that represents the line between p1 and p2. |
Method Summary | |
---|---|
double |
angle()
Returns the angle of the line in degrees. |
double |
angle(QLineF l)
Returns the angle (in degrees) between this line and the given line, taking the direction of the lines into account. |
double |
angleTo(QLineF l)
Returns the angle (in degrees) from this line to the given line, taking the direction of the lines into account. |
QLineF |
clone()
This method is reimplemented for internal reasons |
double |
dx()
Returns the horizontal component of the line's vector. |
double |
dy()
Returns the vertical component of the line's vector. |
static QLineF |
fromPolar(double length,
double angle)
Returns a QLineF with the given length and angle. |
QLineF.IntersectType |
intersect(QLineF line,
QPointF intersectionPoint)
Returns a value indicating whether or not this line intersects with the given line. |
boolean |
isNull()
Returns true if the line is not set up with valid start and end point; otherwise returns false. |
double |
length()
Returns the length of the line. |
QLineF |
normalVector()
Returns a line that is perpendicular to this line with the same starting point and length. |
QPointF |
p1()
Returns the line's start point. |
QPointF |
p2()
Returns the line's end point. |
QPointF |
pointAt(double t)
Returns the point at the parameterized position specified by t. |
void |
readFrom(QDataStream arg__1)
|
void |
setAngle(double angle)
Sets the angle of the line to the given angle (in degrees). |
void |
setLength(double len)
Sets the length of the line to the given length. |
void |
setLine(double x1,
double y1,
double x2,
double y2)
Sets this line to the start in x1, y1 and end in x2, y2. |
void |
setP1(QPointF p1)
Sets the starting point of this line to p1. |
void |
setP2(QPointF p2)
Sets the end point of this line to p2. |
void |
setPoints(QPointF p1,
QPointF p2)
Sets the start point of this line to p1 and the end point of this line to p2. |
QLine |
toLine()
Returns an integer based copy of this line. |
java.lang.String |
toString()
|
void |
translate(double dx,
double dy)
Translates this line the distance specified by dx and dy. |
void |
translate(QPointF p)
Translates this line by the given offset. |
QLineF |
translated(double dx,
double dy)
Returns this line translated the distance specified by dx and dy. |
QLineF |
translated(QPointF p)
Returns this line translated by the given offset. |
QLineF |
unitVector()
Returns the unit vector for this line, i. |
void |
writeTo(QDataStream arg__1)
|
double |
x1()
Returns the x-coordinate of the line's start point. |
double |
x2()
Returns the x-coordinate of the line's end point. |
double |
y1()
Returns the y-coordinate of the line's start point. |
double |
y2()
Returns the y-coordinate of the line's end point. |
Methods inherited from class com.trolltech.qt.QtJambiObject |
---|
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr |
Methods inherited from class com.trolltech.qt.QSignalEmitter |
---|
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread |
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
---|
__qt_signalInitialization |
Methods inherited from class java.lang.Object |
---|
getClass, hashCode, notify, notifyAll, wait, wait, wait |
Methods inherited from interface com.trolltech.qt.QtJambiInterface |
---|
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership |
Constructor Detail |
---|
public QLineF()
public QLineF(QLine line)
QLineF
object from the given integer-based line. toLine()
.
public QLineF(QPointF pt1, QPointF pt2)
public QLineF(double x1, double y1, double x2, double y2)
Method Detail |
---|
public final double 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.
setAngle()
.
public final double angle(QLineF l)
QLineF::UnboundedIntersection
). ![]() | ![]() |
intersect()
.
public final double angleTo(QLineF l)
QLineF::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.
intersect()
.
public final double dx()
dy()
, and pointAt()
.
public final double dy()
dx()
, and pointAt()
.
public final boolean isNull()
public final double length()
setLength()
.
public final QLineF normalVector()
unitVector()
.
public final void writeTo(QDataStream arg__1)
public final void readFrom(QDataStream arg__1)
public final QPointF p1()
setP1()
, x1()
, y1()
, and p2()
.
public final QPointF p2()
setP2()
, x2()
, y2()
, and p1()
.
public final QPointF pointAt(double t)
dx()
, and dy()
.
public final void setAngle(double 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.
angle()
.
public final void setLength(double len)
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.
length()
, and isNull()
.
public final void setLine(double x1, double y1, double x2, double y2)
setP1()
, setP2()
, p1()
, and p2()
.
public final void setP1(QPointF p1)
setP2()
, and p1()
.
public final void setP2(QPointF p2)
setP1()
, and p2()
.
public final void setPoints(QPointF p1, QPointF p2)
setP1()
, setP2()
, p1()
, and p2()
.
public final QLine toLine()
Note that the returned line's start and end points are rounded to the nearest integer.
public final void translate(QPointF p)
public final void translate(double dx, double dy)
public final QLineF translated(QPointF p)
public final QLineF translated(double dx, double dy)
public final QLineF unitVector()
normalVector()
.
public final double x1()
p1()
.
public final double x2()
p2()
.
public final double y1()
p1()
.
public final double y2()
p2()
.
public static QLineF fromPolar(double length, double angle)
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.
public final QLineF.IntersectType intersect(QLineF line, QPointF intersectionPoint)
The actual intersection point is extracted to intersectionPoint (if the pointer is valid). If the lines are parallel, the intersection point is undefined.
public java.lang.String toString()
toString
in class java.lang.Object
public QLineF clone()
clone
in class java.lang.Object
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