Reduce memory usage of QQuickPath for simple paths.

For a single segment line path we can get correct results by
interpolating across just two points, so there no need to allocate
the comparatively large point cache required for more complex paths.

This also correct a normally small interpolation error caused by
including the terminal point in the number of intervals.

Change-Id: I564c3c012b6822831251276951603fca8544a356
Reviewed-by: Michael Brasser <michael.brasser@nokia.com>

1 files changed, 38 insertions, 0 deletions

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)