From f1504289251636e58a8ece4fb48aa9475bc052bb Mon Sep 17 00:00:00 2001
From: Roman Telezhynskyi <dismine@gmail.com>
Date: Tue, 22 Sep 2020 17:05:18 +0300
Subject: [PATCH] Fix bug in VAbstractCurve::CurveIntersectLine.

QLineF::intersects not always accurate on edge cases. We must provide additional check.
---
 src/libs/vgeometry/vabstractcurve.cpp |  4 +-
 src/test/ValentinaTest/tst_varc.cpp   | 63 ++++++++++++++++++++++++++-
 src/test/ValentinaTest/tst_varc.h     |  6 ++-
 3 files changed, 69 insertions(+), 4 deletions(-)

diff --git a/src/libs/vgeometry/vabstractcurve.cpp b/src/libs/vgeometry/vabstractcurve.cpp
index 056c21bde..bf224393c 100644
--- a/src/libs/vgeometry/vabstractcurve.cpp
+++ b/src/libs/vgeometry/vabstractcurve.cpp
@@ -437,7 +437,9 @@ QVector<QPointF> VAbstractCurve::CurveIntersectLine(const QVector<QPointF> &poin
         QPointF crosPoint;
         auto type = Intersects(line, QLineF(points.at(i), points.at(i+1)), &crosPoint);
 
-        if (type == QLineF::BoundedIntersection)
+        // QLineF::intersects not always accurate on edge cases
+        if (type == QLineF::BoundedIntersection ||
+            VGObject::IsPointOnLineSegment (crosPoint, points.at(i), points.at(i+1)))
         {
             intersections.append(crosPoint);
         }
diff --git a/src/test/ValentinaTest/tst_varc.cpp b/src/test/ValentinaTest/tst_varc.cpp
index d50a17b80..61752b5c1 100644
--- a/src/test/ValentinaTest/tst_varc.cpp
+++ b/src/test/ValentinaTest/tst_varc.cpp
@@ -32,9 +32,33 @@
 
 #include <QtTest>
 
+namespace
+{
+void PrepareTestCase(const QPointF &center, qreal startAngle, qreal endAngle)
+{
+    qreal radius = UnitConvertor(1, Unit::Cm, Unit::Px);
+    const qreal threshold = UnitConvertor(2000, Unit::Cm, Unit::Px);
+    while(radius <= threshold)
+    {
+        VArc arc(VPointF(center), radius, startAngle, endAngle);
+        const QVector<QPointF> points = arc.GetPoints();
+
+        const QString testStartAngle = QString("Test start angel. Arc radius %1, start angle %2, end angle %3")
+                                           .arg(radius).arg(startAngle).arg(endAngle);
+        QTest::newRow(qUtf8Printable(testStartAngle)) << center << startAngle << points << points.first() << true;
+
+        const QString testEndAngle = QString("Test end angel. Arc radius %1, start angle %2, end angle %3")
+                                         .arg(radius).arg(startAngle).arg(endAngle);
+        QTest::newRow(qUtf8Printable(testEndAngle)) << center << endAngle << points << points.last() << true;
+
+        radius += UnitConvertor(5, Unit::Cm, Unit::Px);
+    }
+}
+}
+
 //---------------------------------------------------------------------------------------------------------------------
 TST_VArc::TST_VArc(QObject *parent)
-    :QObject(parent)
+    :AbstractTest(parent)
 {}
 
 //---------------------------------------------------------------------------------------------------------------------
@@ -395,3 +419,40 @@ void TST_VArc::TestCutArc()
     qreal segmentsLength = VAbstractCurve::PathLength(arc1.GetPoints()) + VAbstractCurve::PathLength(arc2.GetPoints());
     QVERIFY(qAbs(segmentsLength - VAbstractCurve::PathLength(arc.GetPoints())) <= accuracyPointOnLine);
 }
+
+//---------------------------------------------------------------------------------------------------------------------
+void TST_VArc::TestCurveIntersectAxis_data()
+{
+    QTest::addColumn<QPointF>("basePoint");
+    QTest::addColumn<qreal>("angle");
+    QTest::addColumn<QVector<QPointF>>("curvePoints");
+    QTest::addColumn<QPointF>("crosPoint");
+    QTest::addColumn<bool>("result");
+
+    QPointF basePoint(10, 10);
+
+    PrepareTestCase(basePoint, 0, 15);
+    PrepareTestCase(basePoint, 0, 25);
+    PrepareTestCase(basePoint, 0, 45);
+    PrepareTestCase(basePoint, 0, 90);
+    PrepareTestCase(basePoint, 0, 180);
+    PrepareTestCase(basePoint, 0, 270);
+    PrepareTestCase(basePoint, 180, 315);
+    PrepareTestCase(basePoint, 183, 312);
+}
+
+//---------------------------------------------------------------------------------------------------------------------
+void TST_VArc::TestCurveIntersectAxis()
+{
+    QFETCH(QPointF, basePoint);
+    QFETCH(qreal, angle);
+    QFETCH(QVector<QPointF>, curvePoints);
+    QFETCH(QPointF, crosPoint);
+    QFETCH(bool, result);
+
+    QPointF intersectionPoint;
+    const bool found = VAbstractCurve::CurveIntersectAxis(basePoint, angle, curvePoints, &intersectionPoint);
+    QCOMPARE(found, result);
+
+    Comparison(intersectionPoint, crosPoint);
+}
diff --git a/src/test/ValentinaTest/tst_varc.h b/src/test/ValentinaTest/tst_varc.h
index 0c066e687..f83655bf6 100644
--- a/src/test/ValentinaTest/tst_varc.h
+++ b/src/test/ValentinaTest/tst_varc.h
@@ -29,9 +29,9 @@
 #ifndef TST_VARC_H
 #define TST_VARC_H
 
-#include <QObject>
+#include "../vtest/abstracttest.h"
 
-class TST_VArc : public QObject
+class TST_VArc : public AbstractTest
 {
     Q_OBJECT
 public:
@@ -48,6 +48,8 @@ private slots:
     void TestFlip();
     void TestCutArc_data();
     void TestCutArc();
+    void TestCurveIntersectAxis_data();
+    void TestCurveIntersectAxis();
 };
 
 #endif // TST_VARC_H