/*
* 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 <gdk/gdk.h>
#include "debug/gdk-event-latency-tracker.h"
#include "preferences.h"
namespace Inkscape {
namespace Debug {
GdkEventLatencyTracker::GdkEventLatencyTracker()
: start_seconds(0.0), max_latency(0.0), skew(1.0), last_elapsed(0.0), last_seconds(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;
Inkscape::Preferences *prefs = Inkscape::Preferences::get();
skew = prefs->getDoubleLimited("/debug/latency/skew", 1.0, 0.5, 2.0);
return boost::optional<double>(0.0);
} else {
last_elapsed = elapsed.elapsed();
last_seconds = timestamp_seconds;
double const current_seconds = (last_elapsed * skew) + 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);
}
}
double GdkEventLatencyTracker::getSkew() {
double val = 0.0;
if ((last_elapsed > 0.0) && (last_seconds > 0.0)) {
val = (last_seconds - start_seconds) / last_elapsed;
}
return val;
}
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:fileencoding=utf-8:textwidth=99 :