WebKitTools/QtTestBrowser/fpstimer.cpp
changeset 0 4f2f89ce4247
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebKitTools/QtTestBrowser/fpstimer.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "fpstimer.h"
+
+#include <QDateTime>
+#include <QTimerEvent>
+
+// We save a maximum of 10000 frames, and purge 2000 at a time
+#define MAX_FRAMES_SAVED 10000
+#define FRAMES_TO_PURGE_WHEN_FULL 2000
+// 60 FPS
+#define FPS_MEASURE_INTERVAL 1000 / 60
+
+FpsTimer::FpsTimer(QObject* parent)
+        : QObject(parent)
+{
+}
+
+int FpsTimer::numFrames(int spanMillis)
+{
+    const QTime now = QTime::currentTime();
+
+    int count = 0;
+    for (int i = m_frames.length() - 1; i >= 0; --i, ++count) {
+        int msecs = m_frames[i].msecsTo(now);
+        if (msecs < 0)
+            msecs += 24 * 60 * 60 * 1000;
+        if (msecs > spanMillis)
+            break;
+    }
+    return count;
+}
+
+void FpsTimer::start()
+{
+    m_timer = startTimer(FPS_MEASURE_INTERVAL);
+}
+
+void FpsTimer::stop()
+{
+    killTimer(m_timer);
+    m_frames.clear();
+}
+
+void FpsTimer::timerEvent(QTimerEvent* event)
+{
+    if (event->timerId() !=  m_timer)
+        return;
+    m_frames.append(QTime::currentTime());
+    if (m_frames.length() > MAX_FRAMES_SAVED)
+        m_frames.erase(m_frames.begin(), m_frames.begin() + FRAMES_TO_PURGE_WHEN_FULL);
+}