2 files changed, 62 insertions, 11 deletions

diff --git a/src/quick/util/qquickpath.cpp b/src/quick/util/qquickpath.cpp
index 8dadab620a..8cb6e47028 100644
--- a/src/quick/util/qquickpath.cpp
+++ b/src/quick/util/qquickpath.cpp
@@ -455,6 +455,20 @@ static inline QBezier nextBezier(const QPainterPath &path, int *current, qreal *
     return QBezier();
 }
 
+static inline int segmentCount(const QPainterPath &path, qreal pathLength)
+{
+    // In the really simple case of a single straight line we can interpolate without jitter
+    // between just two points.
+    if (path.elementCount() == 2
+            && path.elementAt(0).type == QPainterPath::MoveToElement
+            && path.elementAt(1).type == QPainterPath::LineToElement) {
+        return 1;
+    }
+    // more points means less jitter between items as they move along the
+    // path, but takes longer to generate
+    return qCeil(pathLength*5);
+}
+
 //derivative of the equation
 static inline qreal slopeAt(qreal t, qreal a, qreal b, qreal c, qreal d)
 {
@@ -467,11 +481,10 @@ void QQuickPath::createPointCache() const
     qreal pathLength = d->pathLength;
     if (pathLength <= 0 || qIsNaN(pathLength))
         return;
-    // more points means less jitter between items as they move along the
-    // path, but takes longer to generate
-    const int points = qCeil(pathLength*5);
+
+    const int segments = segmentCount(d->_path, pathLength);
     const int lastElement = d->_path.elementCount() - 1;
-    d->_pointCache.resize(points+1);
+    d->_pointCache.resize(segments+1);
 
     int currElement = -1;
     qreal bezLength = 0;
@@ -484,7 +497,7 @@ void QQuickPath::createPointCache() const
         qreal prevPercent = 0;
         qreal prevOrigPercent = 0;
         for (int ii = 0; ii < d->_attributePoints.count(); ++ii) {
-            qreal percent = qreal(i)/points;
+            qreal percent = qreal(i)/segments;
             const AttributePoint &point = d->_attributePoints.at(ii);
             if (percent < point.percent || ii == d->_attributePoints.count() - 1) { //### || is special case for very last item
                 qreal elementPercent = (percent - prevPercent);
@@ -657,12 +670,12 @@ QPointF QQuickPath::pointAt(qreal p) const
             return QPointF();
     }
 
-    const int pointCacheSize = d->_pointCache.size();
-    qreal idxf = p*pointCacheSize;
+    const int segmentCount = d->_pointCache.size() - 1;
+    qreal idxf = p*segmentCount;
     int idx1 = qFloor(idxf);
     qreal delta = idxf - idx1;
-    if (idx1 >= pointCacheSize)
-        idx1 = pointCacheSize - 1;
+    if (idx1 > segmentCount)
+        idx1 = segmentCount;
     else if (idx1 < 0)
         idx1 = 0;
 
@@ -671,8 +684,8 @@ QPointF QQuickPath::pointAt(qreal p) const
 
     // interpolate between the two points.
     int idx2 = qCeil(idxf);
-    if (idx2 >= pointCacheSize)
-        idx2 = pointCacheSize - 1;
+    if (idx2 > segmentCount)
+        idx2 = segmentCount;
     else if (idx2 < 0)
         idx2 = 0;
 
diff --git a/tests/auto/quick/qquickpath/tst_qquickpath.cpp b/tests/auto/quick/qquickpath/tst_qquickpath.cpp
index 73e7e6ea38..af5b194bd9 100644
--- a/tests/auto/quick/qquickpath/tst_qquickpath.cpp
+++ b/tests/auto/quick/qquickpath/tst_qquickpath.cpp
@@ -57,6 +57,7 @@ private slots:
     void catmullromCurve();
     void closedCatmullromCurve();
     void svg();
+    void line();
 };
 
 void tst_QuickPath::arc()
@@ -193,6 +194,43 @@ void tst_QuickPath::svg()
     QCOMPARE(pos, QPointF(1000,300));
 }
 
+void tst_QuickPath::line()
+{
+    QQmlEngine engine;
+    QQmlComponent c1(&engine);
+    c1.setData(
+            "import QtQuick 2.0\n"
+            "Path {\n"
+                "startX: 0; startY: 0\n"
+                "PathLine { x: 100; y: 100 }\n"
+            "}", QUrl());
+    QScopedPointer<QObject> o1(c1.create());
+    QQuickPath *path1 = qobject_cast<QQuickPath *>(o1.data());
+    QVERIFY(path1);
+
+    QQmlComponent c2(&engine);
+    c2.setData(
+            "import QtQuick 2.0\n"
+            "Path {\n"
+                "startX: 0; startY: 0\n"
+                "PathLine { x: 50; y: 50 }\n"
+                "PathLine { x: 100; y: 100 }\n"
+            "}", QUrl());
+    QScopedPointer<QObject> o2(c2.create());
+    QQuickPath *path2 = qobject_cast<QQuickPath *>(o2.data());
+    QVERIFY(path2);
+
+    for (int i = 0; i < 167; ++i) {
+        qreal t = i / 167.0;
+
+        QPointF p1 = path1->pointAt(t);
+        QCOMPARE(p1.x(), p1.y());
+
+        QPointF p2 = path2->pointAt(t);
+        QCOMPARE(p1, p2);
+    }
+}
+
 
 QTEST_MAIN(tst_QuickPath)