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path: root/src/corelib/tools/qline.cpp
 ```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 ``` ``````/**************************************************************************** ** ** 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 ``````