/**************************************************************************** ** ** Copyright (C) 2016 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the QtCore module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 3 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL3 included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 3 requirements ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU ** General Public License version 2.0 or (at your option) the GNU General ** Public license version 3 or any later version approved by the KDE Free ** Qt Foundation. The licenses are as published by the Free Software ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 ** included in the packaging of this file. Please review the following ** information to ensure the GNU General Public License requirements will ** be met: https://www.gnu.org/licenses/gpl-2.0.html and ** https://www.gnu.org/licenses/gpl-3.0.html. ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include "qline.h" #include "qdebug.h" #include "qdatastream.h" #include "qmath.h" #include QT_BEGIN_NAMESPACE /*! \class QLine \inmodule QtCore \ingroup painting \brief The 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. \table \row \li \inlineimage qline-point.png \li \inlineimage qline-coordinates.png \endtable 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. \sa QLineF, QPolygon, QRect */ /*! \fn QLine::QLine() Constructs a null line. */ /*! \fn QLine::QLine(const QPoint &p1, const QPoint &p2) Constructs a line object that represents the line between \a p1 and \a p2. */ /*! \fn QLine::QLine(int x1, int y1, int x2, int y2) Constructs a line object that represents the line between (\a x1, \a y1) and (\a x2, \a y2). */ /*! \fn bool QLine::isNull() const Returns \c true if the line is not set up with valid start and end point; otherwise returns \c false. */ /*! \fn QPoint QLine::p1() const Returns the line's start point. \sa x1(), y1(), p2() */ /*! \fn QPoint QLine::p2() const Returns the line's end point. \sa x2(), y2(), p1() */ /*! \fn int QLine::x1() const Returns the x-coordinate of the line's start point. \sa p1() */ /*! \fn int QLine::y1() const Returns the y-coordinate of the line's start point. \sa p1() */ /*! \fn int QLine::x2() const Returns the x-coordinate of the line's end point. \sa p2() */ /*! \fn int QLine::y2() const Returns the y-coordinate of the line's end point. \sa p2() */ /*! \fn int QLine::dx() const Returns the horizontal component of the line's vector. \sa dy() */ /*! \fn int QLine::dy() const Returns the vertical component of the line's vector. \sa dx() */ /*! \fn bool QLine::operator!=(const QLine &line) const Returns \c true if the given \a line is not the same as \e 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. */ /*! \fn bool QLine::operator==(const QLine &line) const Returns \c true if the given \a line is the same as \e 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. */ /*! \fn void QLine::translate(const QPoint &offset) Translates this line by the given \a offset. */ /*! \fn void QLine::translate(int dx, int dy) \overload Translates this line the distance specified by \a dx and \a dy. */ /*! \fn QLine QLine::translated(const QPoint &offset) const \since 4.4 Returns this line translated by the given \a offset. */ /*! \fn QLine QLine::translated(int dx, int dy) const \overload \since 4.4 Returns this line translated the distance specified by \a dx and \a dy. */ /*! \fn QPoint QLine::center() const \since 5.8 Returns the center point of this line. This is equivalent to (p1() + p2()) / 2, except it will never overflow. */ /*! \fn void QLine::setP1(const QPoint &p1) \since 4.4 Sets the starting point of this line to \a p1. \sa setP2(), p1() */ /*! \fn void QLine::setP2(const QPoint &p2) \since 4.4 Sets the end point of this line to \a p2. \sa setP1(), p2() */ /*! \fn void QLine::setPoints(const QPoint &p1, const QPoint &p2) \since 4.4 Sets the start point of this line to \a p1 and the end point of this line to \a p2. \sa setP1(), setP2(), p1(), p2() */ /*! \fn void QLine::setLine(int x1, int y1, int x2, int y2) \since 4.4 Sets this line to the start in \a x1, \a y1 and end in \a x2, \a y2. \sa setP1(), setP2(), p1(), p2() */ #ifndef QT_NO_DEBUG_STREAM QDebug operator<<(QDebug dbg, const QLine &p) { QDebugStateSaver saver(dbg); dbg.nospace() << "QLine(" << p.p1() << ',' << p.p2() << ')'; return dbg; } #endif #ifndef QT_NO_DATASTREAM /*! \relates QLine Writes the given \a line to the given \a stream and returns a reference to the stream. \sa {Serializing Qt Data Types} */ QDataStream &operator<<(QDataStream &stream, const QLine &line) { stream << line.p1() << line.p2(); return stream; } /*! \relates QLine Reads a line from the given \a stream into the given \a line and returns a reference to the stream. \sa {Serializing Qt Data Types} */ QDataStream &operator>>(QDataStream &stream, QLine &line) { QPoint p1, p2; stream >> p1; stream >> p2; line = QLine(p1, p2); return stream; } #endif // QT_NO_DATASTREAM #ifndef M_2PI #define M_2PI 6.28318530717958647692528676655900576 #endif /*! \class QLineF \inmodule QtCore \ingroup painting \brief 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. \table \row \li \inlineimage qline-point.png \li \inlineimage qline-coordinates.png \endtable 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 intersect() function determines the IntersectType 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. \section1 Constraints QLine is limited to the minimum and maximum values for the \c int type. Operations on a QLine that could potentially result in values outside this range will result in undefined behavior. \sa QLine, QPolygonF, QRectF */ /*! \enum QLineF::IntersectType Describes the intersection between two lines. \table \row \li \inlineimage qlinef-unbounded.png \li \inlineimage qlinef-bounded.png \row \li QLineF::UnboundedIntersection \li QLineF::BoundedIntersection \endtable \value NoIntersection Indicates that the lines do not intersect; i.e. they are parallel. \value 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. intersect() will also return this value if the intersect point is within the start and end point of only one of the lines. \value BoundedIntersection The two lines intersect with each other within the start and end points of each line. \sa intersect() */ /*! \fn QLineF::QLineF() Constructs a null line. */ /*! \fn QLineF::QLineF(const QPointF &p1, const QPointF &p2) Constructs a line object that represents the line between \a p1 and \a p2. */ /*! \fn QLineF::QLineF(qreal x1, qreal y1, qreal x2, qreal y2) Constructs a line object that represents the line between (\a x1, \a y1) and (\a x2, \a y2). */ /*! \fn QLineF::QLineF(const QLine &line) Construct a QLineF object from the given integer-based \a line. \sa toLine() */ /*! \fn bool QLineF::isNull() const Returns \c true if the line is not set up with valid start and end point; otherwise returns \c false. */ /*! \fn QPointF QLineF::p1() const Returns the line's start point. \sa x1(), y1(), p2() */ /*! \fn QPointF QLineF::p2() const Returns the line's end point. \sa x2(), y2(), p1() */ /*! \fn QLine QLineF::toLine() const Returns an integer based copy of this line. Note that the returned line's start and end points are rounded to the nearest integer. \sa QLineF() */ /*! \fn qreal QLineF::x1() const Returns the x-coordinate of the line's start point. \sa p1() */ /*! \fn qreal QLineF::y1() const Returns the y-coordinate of the line's start point. \sa p1() */ /*! \fn qreal QLineF::x2() const Returns the x-coordinate of the line's end point. \sa p2() */ /*! \fn qreal QLineF::y2() const Returns the y-coordinate of the line's end point. \sa p2() */ /*! \fn qreal QLineF::dx() const Returns the horizontal component of the line's vector. \sa dy(), pointAt() */ /*! \fn qreal QLineF::dy() const Returns the vertical component of the line's vector. \sa dx(), pointAt() */ /*! \fn QLineF::setLength(qreal length) Sets the length of the line to the given \a 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. \sa length(), isNull() */ /*! \fn QLineF QLineF::normalVector() const Returns a line that is perpendicular to this line with the same starting point and length. \image qlinef-normalvector.png \sa unitVector() */ /*! \fn bool QLineF::operator!=(const QLineF &line) const Returns \c true if the given \a line is not the same as \e 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. */ /*! \fn bool QLineF::operator==(const QLineF &line) const Returns \c true if the given \a 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. */ /*! \fn qreal QLineF::pointAt(qreal t) const Returns the point at the parameterized position specified by \a t. The function returns the line's start point if t = 0, and its end point if t = 1. \sa dx(), dy() */ /*! Returns the length of the line. \sa setLength() */ qreal QLineF::length() const { qreal x = pt2.x() - pt1.x(); qreal y = pt2.y() - pt1.y(); return qSqrt(x*x + y*y); } /*! \since 4.4 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). \sa setAngle() */ qreal QLineF::angle() const { const qreal dx = pt2.x() - pt1.x(); const qreal dy = pt2.y() - pt1.y(); const qreal theta = qAtan2(-dy, dx) * 360.0 / M_2PI; const qreal theta_normalized = theta < 0 ? theta + 360 : theta; if (qFuzzyCompare(theta_normalized, qreal(360))) return qreal(0); else return theta_normalized; } /*! \since 4.4 Sets the angle of the line to the given \a 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. \sa angle() */ void QLineF::setAngle(qreal angle) { const qreal angleR = angle * M_2PI / 360.0; const qreal l = length(); const qreal dx = qCos(angleR) * l; const qreal dy = -qSin(angleR) * l; pt2.rx() = pt1.x() + dx; pt2.ry() = pt1.y() + dy; } /*! \since 4.4 Returns a QLineF with the given \a length and \a 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. */ QLineF QLineF::fromPolar(qreal length, qreal angle) { const qreal angleR = angle * M_2PI / 360.0; return QLineF(0, 0, qCos(angleR) * length, -qSin(angleR) * length); } /*! Returns the unit vector for this line, i.e a line starting at the same point as \e this line with a length of 1.0. \sa normalVector() */ QLineF QLineF::unitVector() const { qreal x = pt2.x() - pt1.x(); qreal y = pt2.y() - pt1.y(); qreal len = qSqrt(x*x + y*y); QLineF f(p1(), QPointF(pt1.x() + x/len, pt1.y() + y/len)); #ifndef QT_NO_DEBUG if (qAbs(f.length() - 1) >= 0.001) qWarning("QLine::unitVector: New line does not have unit length"); #endif return f; } /*! \fn QLineF::IntersectType QLineF::intersect(const QLineF &line, QPointF *intersectionPoint) const Returns a value indicating whether or not \e this line intersects with the given \a line. The actual intersection point is extracted to \a intersectionPoint (if the pointer is valid). If the lines are parallel, the intersection point is undefined. */ QLineF::IntersectType QLineF::intersect(const QLineF &l, QPointF *intersectionPoint) const { // ipmlementation is based on Graphics Gems III's "Faster Line Segment Intersection" const QPointF a = pt2 - pt1; const QPointF b = l.pt1 - l.pt2; const QPointF c = pt1 - l.pt1; const qreal denominator = a.y() * b.x() - a.x() * b.y(); if (denominator == 0 || !qt_is_finite(denominator)) return NoIntersection; const qreal reciprocal = 1 / denominator; const qreal na = (b.y() * c.x() - b.x() * c.y()) * reciprocal; if (intersectionPoint) *intersectionPoint = pt1 + a * na; if (na < 0 || na > 1) return UnboundedIntersection; const qreal nb = (a.x() * c.y() - a.y() * c.x()) * reciprocal; if (nb < 0 || nb > 1) return UnboundedIntersection; return BoundedIntersection; } /*! \fn void QLineF::translate(const QPointF &offset) Translates this line by the given \a offset. */ /*! \fn void QLineF::translate(qreal dx, qreal dy) \overload Translates this line the distance specified by \a dx and \a dy. */ /*! \fn QLineF QLineF::translated(const QPointF &offset) const \since 4.4 Returns this line translated by the given \a offset. */ /*! \fn QLineF QLineF::translated(qreal dx, qreal dy) const \overload \since 4.4 Returns this line translated the distance specified by \a dx and \a dy. */ /*! \fn QPointF QLineF::center() const \since 5.8 Returns the center point of this line. This is equivalent to 0.5 * p1() + 0.5 * p2(). */ /*! \fn void QLineF::setP1(const QPointF &p1) \since 4.4 Sets the starting point of this line to \a p1. \sa setP2(), p1() */ /*! \fn void QLineF::setP2(const QPointF &p2) \since 4.4 Sets the end point of this line to \a p2. \sa setP1(), p2() */ /*! \fn void QLineF::setPoints(const QPointF &p1, const QPointF &p2) \since 4.4 Sets the start point of this line to \a p1 and the end point of this line to \a p2. \sa setP1(), setP2(), p1(), p2() */ /*! \fn void QLineF::setLine(qreal x1, qreal y1, qreal x2, qreal y2) \since 4.4 Sets this line to the start in \a x1, \a y1 and end in \a x2, \a y2. \sa setP1(), setP2(), p1(), p2() */ /*! \fn qreal QLineF::angleTo(const QLineF &line) const \since 4.4 Returns the angle (in degrees) from this line to the given \a 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 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 \a line, going counter-clockwise. \sa intersect() */ qreal QLineF::angleTo(const QLineF &l) const { if (isNull() || l.isNull()) return 0; const qreal a1 = angle(); const qreal a2 = l.angle(); const qreal delta = a2 - a1; const qreal delta_normalized = delta < 0 ? delta + 360 : delta; if (qFuzzyCompare(delta, qreal(360))) return 0; else return delta_normalized; } /*! \fn qreal QLineF::angle(const QLineF &line) const \obsolete Returns the angle (in degrees) between this line and the given \a 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 QLineF::UnboundedIntersection). \table \row \li \inlineimage qlinef-angle-identicaldirection.png \li \inlineimage qlinef-angle-oppositedirection.png \endtable When the lines are parallel, this function returns 0 if they have the same direction; otherwise it returns 180. \sa intersect() */ qreal QLineF::angle(const QLineF &l) const { if (isNull() || l.isNull()) return 0; qreal cos_line = (dx()*l.dx() + dy()*l.dy()) / (length()*l.length()); qreal rad = 0; // only accept cos_line in the range [-1,1], if it is outside, use 0 (we return 0 rather than PI for those cases) if (cos_line >= -1.0 && cos_line <= 1.0) rad = qAcos( cos_line ); return rad * 360 / M_2PI; } #ifndef QT_NO_DEBUG_STREAM QDebug operator<<(QDebug dbg, const QLineF &p) { QDebugStateSaver saver(dbg); dbg.nospace() << "QLineF(" << p.p1() << ',' << p.p2() << ')'; return dbg; } #endif #ifndef QT_NO_DATASTREAM /*! \relates QLineF Writes the given \a line to the given \a stream and returns a reference to the stream. \sa {Serializing Qt Data Types} */ QDataStream &operator<<(QDataStream &stream, const QLineF &line) { stream << line.p1() << line.p2(); return stream; } /*! \relates QLineF Reads a line from the given \a stream into the given \a line and returns a reference to the stream. \sa {Serializing Qt Data Types} */ QDataStream &operator>>(QDataStream &stream, QLineF &line) { QPointF start, end; stream >> start; stream >> end; line = QLineF(start, end); return stream; } #endif // QT_NO_DATASTREAM QT_END_NAMESPACE