1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Inkscape::Debug::GdkEventLatencyTracker - tracks backlog of GDK events 4 * 5 * Authors: 6 * MenTaLguY <mental@rydia.net> 7 * 8 * Copyright (C) 2008 MenTaLguY 9 * 10 * Released under GNU GPL v2+, read the file 'COPYING' for more information. 11 */ 12 13 #include <gdk/gdk.h> 14 15 #include "debug/gdk-event-latency-tracker.h" 16 #include "preferences.h" 17 18 namespace Inkscape { 19 namespace Debug { 20 GdkEventLatencyTracker()21GdkEventLatencyTracker::GdkEventLatencyTracker() 22 : start_seconds(0.0), max_latency(0.0), skew(1.0), last_elapsed(0.0), last_seconds(0.0) 23 { 24 elapsed.stop(); 25 elapsed.reset(); 26 } 27 process(GdkEvent const * event)28std::optional<double> GdkEventLatencyTracker::process(GdkEvent const *event) { 29 guint32 const timestamp=gdk_event_get_time(const_cast<GdkEvent *>(event)); 30 if (timestamp == GDK_CURRENT_TIME) { 31 return std::optional<double>(); 32 } 33 double const timestamp_seconds = timestamp / 1000.0; 34 35 if (start_seconds == 0.0) { 36 elapsed.start(); 37 start_seconds = timestamp_seconds; 38 Inkscape::Preferences *prefs = Inkscape::Preferences::get(); 39 skew = prefs->getDoubleLimited("/debug/latency/skew", 1.0, 0.5, 2.0); 40 return std::optional<double>(0.0); 41 } else { 42 last_elapsed = elapsed.elapsed(); 43 last_seconds = timestamp_seconds; 44 double const current_seconds = (last_elapsed * skew) + start_seconds; 45 double delta = current_seconds - timestamp_seconds; 46 if (delta < 0.0) { 47 start_seconds += -delta; 48 delta = 0.0; 49 } else if (delta > max_latency) { 50 max_latency = delta; 51 } 52 return std::optional<double>(delta); 53 } 54 } 55 getSkew()56double GdkEventLatencyTracker::getSkew() { 57 double val = 0.0; 58 if ((last_elapsed > 0.0) && (last_seconds > 0.0)) { 59 val = (last_seconds - start_seconds) / last_elapsed; 60 } 61 return val; 62 } 63 default_tracker()64GdkEventLatencyTracker &GdkEventLatencyTracker::default_tracker() { 65 static GdkEventLatencyTracker tracker; 66 return tracker; 67 } 68 69 } 70 } 71 72 /* 73 Local Variables: 74 mode:c++ 75 c-file-style:"stroustrup" 76 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +)) 77 indent-tabs-mode:nil 78 fill-column:99 79 End: 80 */ 81 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 : 82