From f1d7caaba5a1d29f4e69e82ac32e6aa642dbfc46 Mon Sep 17 00:00:00 2001 From: Roman Telezhynskyi Date: Thu, 7 May 2015 12:39:08 +0300 Subject: [PATCH] Fixed issue #298. Segmented Curve isn't selected in Seam Allowance tool. --HG-- branch : release --- src/app/geometry/vgobject.cpp | 63 +++++++++++++++++++++++++++-------- src/app/geometry/vgobject.h | 7 ++-- 2 files changed, 55 insertions(+), 15 deletions(-) diff --git a/src/app/geometry/vgobject.cpp b/src/app/geometry/vgobject.cpp index 61ab1d3ed..eb027ac4a 100644 --- a/src/app/geometry/vgobject.cpp +++ b/src/app/geometry/vgobject.cpp @@ -352,30 +352,67 @@ void VGObject::LineCoefficients(const QLineF &line, qreal *a, qreal *b, qreal *c } //--------------------------------------------------------------------------------------------------------------------- +/** + * @brief IsPointOnLineSegment Check if the point is on the line segment. + * + * Original idea http://www.sunshine2k.de/coding/java/PointOnLine/PointOnLine.html + */ bool VGObject::IsPointOnLineSegment(const QPointF &t, const QPointF &p1, const QPointF &p2) { - const qreal eps = 1e-8; - - qreal a = p2.y() - p1.y(); - qreal b = p1.x() - p2.x(); - qreal c = - a * p1.x() - b * p1.y(); - if (qAbs(a * t.x() + b * t.y() + c) > eps) + // The test point must lie inside the bounding box spanned by the two line points. + if (not ( (p1.x() <= t.x() && t.x() <= p2.x()) || (p2.x() <= t.x() && t.x() <= p1.x()) )) { + // test point not in x-range return false; } - return PointInBox (t, p1, p2); + if (not ( (p1.y() <= t.y() && t.y() <= p2.y()) || (p2.y() <= t.y() && t.y() <= p1.y()) )) + { + // test point not in y-range + return false; + } + + // Test via the perp dot product (PDP) + return IsPointOnLineviaPDP(t, p1, p2); } //--------------------------------------------------------------------------------------------------------------------- -bool VGObject::PointInBox(const QPointF &t, const QPointF &p1, const QPointF &p2) +/** + * @brief IsPointOnLineviaPDP use the perp dot product (PDP) way. + * + * The pdp is zero only if the t lies on the line e1 = vector from p1 to p2. + */ +bool VGObject::IsPointOnLineviaPDP(const QPointF &t, const QPointF &p1, const QPointF &p2) { - const qreal eps = 1e-8; + return ( qAbs(PerpDotProduct(p1, p2, t) < GetEpsilon(p1, p2)) ); +} - return (qAbs (t.x() - qMin(p1.x(), p2.x())) <= eps || qMin(p1.x(), p2.x()) <= t.x()) && - (qAbs (qMax(p1.x(), p2.x()) - t.x()) <= eps || qMax(p1.x(), p2.x()) >= t.x()) && - (qAbs (t.y() - qMin(p1.y(), p2.y())) <= eps || qMin(p1.y(), p2.y()) <= t.y()) && - (qAbs (qMax(p1.y(), p2.y()) - t.y()) <= eps || qMax(p1.y(), p2.y()) >= t.y()); +//--------------------------------------------------------------------------------------------------------------------- +/** + * @brief PerpDotProduct Calculates the area of the parallelogram of the three points. + * This is actually the same as the area of the triangle defined by the three points, multiplied by 2. + * @return 2 * triangleArea(a,b,c) + */ +double VGObject::PerpDotProduct(const QPointF &t, const QPointF &p1, const QPointF &p2) +{ + return (p1.x() - t.x()) * (p2.y() - t.y()) - (p1.y() - t.y()) * (p2.x() - t.x()); +} + +//--------------------------------------------------------------------------------------------------------------------- +/** + * @brief GetEpsilon solve the floating-point accuraccy problem. + * + * There is the floating-point accuraccy problem, so instead of checking against zero, some epsilon value has to be + * used. Because the size of the pdp value depends on the length of the vectors, no static value can be used. One + * approach is to compare the pdp/area value to the fraction of another area which also depends on the length of the + * line e1=(p1, p2), e.g. the area of the square with side e1 which is computed below + */ +double VGObject::GetEpsilon(const QPointF &p1, const QPointF &p2) +{ + const int dx1 = p2.toPoint().x() - p1.toPoint().x(); + const int dy1 = p2.toPoint().y() - p1.toPoint().y(); + const double epsilon = 0.003 * (dx1 * dx1 + dy1 * dy1); + return epsilon; } //--------------------------------------------------------------------------------------------------------------------- diff --git a/src/app/geometry/vgobject.h b/src/app/geometry/vgobject.h index eff533f3d..ba302d687 100644 --- a/src/app/geometry/vgobject.h +++ b/src/app/geometry/vgobject.h @@ -78,13 +78,16 @@ public: static QPointF ClosestPoint(const QLineF &line, const QPointF &point); static QPointF addVector (const QPointF &p, const QPointF &p1, const QPointF &p2, qreal k); static void LineCoefficients(const QLineF &line, qreal *a, qreal *b, qreal *c); - static bool PointInSegment (const QPointF &t, const QPointF &p1, const QPointF &p2); - static bool PointInBox (const QPointF &t, const QPointF &p1, const QPointF &p2); + static bool IsPointOnLineSegment (const QPointF &t, const QPointF &p1, const QPointF &p2); static QVector GetReversePoints(const QVector &points); static int GetLengthContour(const QVector &contour, const QVector &newPoints); private: QSharedDataPointer d; + + static bool IsPointOnLineviaPDP(const QPointF &t, const QPointF &p1, const QPointF &p2); + static double PerpDotProduct(const QPointF &t, const QPointF &p1, const QPointF &p2); + static double GetEpsilon(const QPointF &p1, const QPointF &p2); }; #endif // VGOBJECT_H