instrument event latency

(bzr r6231)

1 files changed, 65 insertions, 0 deletions

diff --git a/src/debug/gdk-event-latency-tracker.cpp b/src/debug/gdk-event-latency-tracker.cpp
new file mode 100644
index 000000000..8e34d2fc2
--- /dev/null
+++ b/src/debug/gdk-event-latency-tracker.cpp
@@ -0,0 +1,65 @@
+/*
+ * Inkscape::Debug::GdkEventLatencyTracker - tracks backlog of GDK events
+ *
+ * Authors:
+ *   MenTaLguY <mental@rydia.net>
+ *
+ * Copyright (C) 2008 MenTaLguY
+ *
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#include "debug/gdk-event-latency-tracker.h"
+
+namespace Inkscape {
+namespace Debug {
+
+GdkEventLatencyTracker::GdkEventLatencyTracker()
+: start_seconds(0.0), max_latency(0.0)
+{
+    elapsed.stop();
+    elapsed.reset();
+}
+
+boost::optional<double> GdkEventLatencyTracker::process(GdkEvent const *event) {
+    guint32 const timestamp=gdk_event_get_time(const_cast<GdkEvent *>(event));
+    if (timestamp == GDK_CURRENT_TIME) {
+        return boost::optional<double>();
+    }
+    double const timestamp_seconds = timestamp / 1000.0;
+
+    if (start_seconds == 0.0) {
+        elapsed.start();
+        start_seconds = timestamp_seconds;
+        return boost::optional<double>(0.0);
+    } else {
+        double const current_seconds = elapsed.elapsed() + start_seconds;
+        double delta = current_seconds - timestamp_seconds;
+        if (delta < 0.0) {
+            start_seconds += -delta;
+            delta = 0.0;
+        } else if (delta > max_latency) {
+            max_latency = delta;
+        }
+        return boost::optional<double>(delta);
+    }
+}
+
+GdkEventLatencyTracker &GdkEventLatencyTracker::default_tracker() {
+    static GdkEventLatencyTracker tracker;
+    return tracker;
+}
+
+}
+}
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :