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-rw-r--r--src/debug/gdk-event-latency-tracker.cpp81
1 files changed, 81 insertions, 0 deletions
diff --git a/src/debug/gdk-event-latency-tracker.cpp b/src/debug/gdk-event-latency-tracker.cpp
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Inkscape::Debug::GdkEventLatencyTracker - tracks backlog of GDK events
+ *
+ * Authors:
+ * MenTaLguY <mental@rydia.net>
+ *
+ * Copyright (C) 2008 MenTaLguY
+ *
+ * Released under GNU GPL v2+, 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();
+}
+
+std::optional<double> GdkEventLatencyTracker::process(GdkEvent const *event) {
+ guint32 const timestamp=gdk_event_get_time(const_cast<GdkEvent *>(event));
+ if (timestamp == GDK_CURRENT_TIME) {
+ return std::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 std::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 std::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 :