Fix segmenting a simple curve.

ChangeLog.txt

@@ -17,6 +17,7 @@
 - Unit type for increments.
 - Support for options Force Flipping and Forbid Flipping in Puzzle.
 - Remember selected dimension values.
+- Fix segmenting a simple curve.
 
 # Valentina 0.7.51 April 18, 2022
 - Z value change for a layout piece.

src/libs/vgeometry/vabstractcubicbezier.cpp

@@ -524,7 +524,7 @@ auto VAbstractCubicBezier::GetParmT(qreal length) const -> qreal
         length = base;
     }
 
-    Q_DECL_RELAXED_CONSTEXPR qreal eps = ToPixel(0.001, Unit::Mm);
+    Q_DECL_RELAXED_CONSTEXPR qreal eps = ToPixel(0.0001, Unit::Mm);
     qreal parT = 0.5;
     qreal step = parT;
     qreal splLength = 0;

src/libs/vtools/tools/drawTools/toolpoint/toolsinglepoint/toolcut/vtoolcutspline.cpp

@@ -152,6 +152,9 @@ VToolCutSpline* VToolCutSpline::Create(VToolCutInitData &initData)
     auto spline1 = QSharedPointer<VAbstractBezier>(new VSpline(spl->GetP1(), spl1p2, spl1p3, *p));
     auto spline2 = QSharedPointer<VAbstractBezier>(new VSpline(*p, spl2p2, spl2p3, spl->GetP4()));
 
+    spline1->SetApproximationScale(spl->GetApproximationScale());
+    spline2->SetApproximationScale(spl->GetApproximationScale());
+
     spline1->SetAliasSuffix(initData.aliasSuffix1);
     spline2->SetAliasSuffix(initData.aliasSuffix2);
 

src/test/ValentinaTest/tst_vspline.cpp

@@ -849,6 +849,33 @@ void TST_VSpline::TestFlip()
     QCOMPARE(spl.GetC2Length(), res.GetC2Length());
 }
 
+//---------------------------------------------------------------------------------------------------------------------
+// See file valentina_private_collection/bugs/men_jacket/issue_cut_spline.val (private collection)
+void TST_VSpline::TestCutSpline()
+{
+    VPointF p1(187.31716535433043, 51.31464566929152, QStringLiteral("p1"), 140.42872440944885, -22.62372283464567);
+    VPointF p4(-991.8954330708666, 9.739842519685212, QStringLiteral("p4"), 9.999987401574804, 15.0);
+
+    VSpline spl(p1, p4, 181.0, QStringLiteral("181"), 356.0, QStringLiteral("356"), 548.7874015748031,
+                QStringLiteral("Line_Г3_Г6*1.1"), 226.7716535433071, QStringLiteral("6"));
+    spl.SetApproximationScale(0.5);
+
+    const QString name(QStringLiteral("з"));
+    const qreal result = 1.35; // Correct distance in cm.
+    QPointF spl1p2, spl1p3, spl2p2, spl2p3;
+    QPointF point = spl.CutSpline(UnitConvertor(result, Unit::Cm, Unit::Px), spl1p2, spl1p3, spl2p2, spl2p3, name);
+
+    VPointF p(point, name, -16.590651968503941, 37.574173228346453);
+
+    VSpline spline1(spl.GetP1(), spl1p2, spl1p3, p);
+    spline1.SetApproximationScale(0.5);
+
+    // Size 54 produces incorrect spline segment distance
+
+    Q_DECL_RELAXED_CONSTEXPR qreal eps = ToPixel(0.0001, Unit::Mm);
+    QVERIFY(UnitConvertor(spline1.GetLength(), Unit::Px, Unit::Cm) - result < eps);
+}
+
 //---------------------------------------------------------------------------------------------------------------------
 void TST_VSpline::CompareSplines(const VSpline &spl1, const VSpline &spl2) const
 {

src/test/ValentinaTest/tst_vspline.h

@@ -56,6 +56,7 @@ private slots:
     void TestLengthByPoint();
     void TestFlip_data();
     void TestFlip();
+    void TestCutSpline();
 
 private:
     // cppcheck-suppress unknownMacro