1 files changed, 83 insertions, 0 deletions
diff --git a/krdc/vnc/pointerlatencyometer.h b/krdc/vnc/pointerlatencyometer.h
new file mode 100644
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+++ b/krdc/vnc/pointerlatencyometer.h
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+/***************************************************************************
+                  pointerlatencyometer.h  - measuring pointer latency
+                             -------------------
+    begin                : Wed Jun 30 12:04:44 CET 2002
+    copyright            : (C) 2002-2003 by Tim Jansen
+    email                : [email protected]
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include <qdatetime.h>
+#include <kdebug.h>
+
+struct PointerState {
+	int x, y;
+	QTime timestamp;
+};
+
+class PointerLatencyOMeter {
+private:
+	enum { stateCapacity = 30, maximumLatency = 1000 };
+	PointerState states[stateCapacity];
+	int firstState, stateNum;
+	float last3Latency, last20Latency;
+
+public:
+	PointerLatencyOMeter() :
+		firstState(0),
+		stateNum(0),
+		last3Latency(125),
+		last20Latency(25) {
+	}
+	
+	// registers a client pointer state
+	void registerPointerState(int x, int y) {
+		if (stateNum == stateCapacity)
+			stateNum--;
+		if (firstState == 0)
+			firstState = stateCapacity-1;
+		else
+			firstState--;
+		states[firstState].x = x;
+		states[firstState].y = y;
+		states[firstState].timestamp.start();
+		stateNum++;
+	}
+
+	/* Returns true if pointer should be visible */
+	bool registerLatency(int msecs) {
+		last3Latency = ((last3Latency * 2.0) + msecs) / 3.0;
+		last20Latency = ((last20Latency * 19.0) + msecs) / 20.0;
+
+		if (msecs >= maximumLatency) 
+			return true;
+		if (last3Latency > (1000/4))
+			return true;
+		return last20Latency > (1000/12);
+	}
+
+	// Called with server-side coordinates.
+	// Returns true if pointer should be visible
+	bool handlePointerEvent(int x, int y) {
+		for (int i = stateNum-1; i >= 0; i--) {
+			int idx = (i+firstState) % stateCapacity;
+			if ((states[idx].x != x) ||
+			    (states[idx].y != y)) 
+				continue;
+			
+			stateNum = i;
+			int l = states[idx].timestamp.elapsed();
+			return registerLatency((l > maximumLatency) ? maximumLatency : l);
+		}
+		return true;
+	}
+
+};