Make QTimeLine::start() restart from the beginning as the documentation says.

The documentation implies that start restarts. Which it did, but only if the
timeline was finished _and_ the duration hadn't been changed meanwhile.
So after a setDuration(), start() would do nothing, which was unexpected.

Merge-request: 1145
Reviewed-by: Olivier Goffart <ogoffart@trolltech.com>

2 files changed, 44 insertions, 6 deletions

diff --git a/src/corelib/tools/qtimeline.cpp b/src/corelib/tools/qtimeline.cpp
index e32fc03..7402ba6 100644
--- a/src/corelib/tools/qtimeline.cpp
+++ b/src/corelib/tools/qtimeline.cpp
@@ -663,6 +663,7 @@ qreal QTimeLine::valueForTime(int msec) const
     second). You can change the update interval by calling
     setUpdateInterval().
 
+    The timeline will start from position 0, or the end if going backward.
     If you want to resume a stopped timeline without restarting, you can call
     resume() instead.
 
@@ -675,10 +676,8 @@ void QTimeLine::start()
         qWarning("QTimeLine::start: already running");
         return;
     }
-    int curTime = d->currentTime;
-    if (curTime == d->duration && d->direction == Forward)
-        curTime = 0;
-    else if (curTime == 0 && d->direction == Backward)
+    int curTime = 0;
+    if (d->direction == Backward)
         curTime = d->duration;
     d->timerId = startTimer(d->updateInterval);
     d->startTime = curTime;
@@ -694,7 +693,7 @@ void QTimeLine::start()
     frame and value at regular intervals.
 
     In contrast to start(), this function does not restart the timeline before
-    is resumes.
+    it resumes.
 
     \sa start(), updateInterval(), frameChanged(), valueChanged()
 */
diff --git a/tests/auto/qtimeline/tst_qtimeline.cpp b/tests/auto/qtimeline/tst_qtimeline.cpp
index e6e75ff..4ce1f4b 100644
--- a/tests/auto/qtimeline/tst_qtimeline.cpp
+++ b/tests/auto/qtimeline/tst_qtimeline.cpp
@@ -81,6 +81,7 @@ private slots:
     void outOfRange();
     void stateInFinishedSignal();
     void resume();
+    void restart();
 
 protected slots:
     void finishedSlot();
@@ -177,7 +178,7 @@ void tst_QTimeLine::currentTime()
     QCOMPARE(spy.count(), 1);
     spy.clear();
     QCOMPARE(timeLine.currentTime(), timeLine.duration()/2);
-    timeLine.start();
+    timeLine.resume();
     // Let it update on its own
     QTest::qWait(timeLine.duration()/4);
     QCOMPARE(timeLine.state(), QTimeLine::Running);
@@ -699,5 +700,43 @@ void tst_QTimeLine::resume()
     }
 }
 
+void tst_QTimeLine::restart()
+{
+    QTimeLine timeLine(100);
+    timeLine.setFrameRange(0,9);
+
+    timeLine.start();
+    QTest::qWait(timeLine.duration()*2);
+    QCOMPARE(timeLine.currentFrame(), timeLine.endFrame());
+    QCOMPARE(timeLine.state(), QTimeLine::NotRunning);
+
+    // A restart with the same duration
+    timeLine.start();
+    QCOMPARE(timeLine.state(), QTimeLine::Running);
+    QCOMPARE(timeLine.currentFrame(), timeLine.startFrame());
+    QCOMPARE(timeLine.currentTime(), 0);
+    QTest::qWait(250);
+    QCOMPARE(timeLine.currentFrame(), timeLine.endFrame());
+    QCOMPARE(timeLine.state(), QTimeLine::NotRunning);
+
+    // Set a smaller duration and restart
+    timeLine.setDuration(50);
+    timeLine.start();
+    QCOMPARE(timeLine.state(), QTimeLine::Running);
+    QCOMPARE(timeLine.currentFrame(), timeLine.startFrame());
+    QCOMPARE(timeLine.currentTime(), 0);
+    QTest::qWait(250);
+    QCOMPARE(timeLine.currentFrame(), timeLine.endFrame());
+    QCOMPARE(timeLine.state(), QTimeLine::NotRunning);
+
+    // Set a longer duration and restart
+    timeLine.setDuration(150);
+    timeLine.start();
+    QCOMPARE(timeLine.state(), QTimeLine::Running);
+    QCOMPARE(timeLine.currentFrame(), timeLine.startFrame());
+    QCOMPARE(timeLine.currentTime(), 0);
+}
+
 QTEST_MAIN(tst_QTimeLine)
+
 #include "tst_qtimeline.moc"