From 4aa9174e76fb16ca0326644b36299944cf67ed58 Mon Sep 17 00:00:00 2001 From: Camilla Berglund Date: Wed, 3 Sep 2014 01:44:08 +0200 Subject: [PATCH] Clarified comments for X11 key repeat hack. --- src/x11_window.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/src/x11_window.c b/src/x11_window.c index 3d1863d5..9b9ae20b 100644 --- a/src/x11_window.c +++ b/src/x11_window.c @@ -624,10 +624,10 @@ static void processEvent(XEvent *event) if (!_glfw.x11.xkb.detectable) { - // XKB detectable key repeat is not supported on this server - // For key repeats we will get KeyRelease/KeyPress pairs with - // similar or identical time stamps. User selected key repeat - // filtering is handled in _glfwInputKey/_glfwInputChar. + // HACK: Key repeat events will arrive as KeyRelease/KeyPress + // pairs with similar or identical time stamps + // The key repeat logic in _glfwInputKey expectes only key + // presses to repeat, so detect and discard release events if (XEventsQueued(_glfw.x11.display, QueuedAfterReading)) { XEvent nextEvent; @@ -637,15 +637,16 @@ static void processEvent(XEvent *event) nextEvent.xkey.window == event->xkey.window && nextEvent.xkey.keycode == event->xkey.keycode) { - // This last check is a hack to work around key repeats - // leaking through due to some sort of time drift - // Toshiyuki Takahashi can press a button 16 times per - // second so it's fairly safe to assume that no human is - // pressing the key 50 times per second (value is ms) + // HACK: Repeat events sometimes leak through due to + // some sort of time drift, so add an epsilon + // Toshiyuki Takahashi can press a button 16 times + // per second so it's fairly safe to assume that + // no human is pressing the key 50 times per + // second (value is ms) if ((nextEvent.xkey.time - event->xkey.time) < 20) { - // This is a server-generated key repeat event - // Do not report anything for this event + // This is very likely a server-generated key repeat + // event, so ignore it break; } }