* Finally rewrote the filthy, busy-looping, mouse tracking in Tracker.

The new asynchronous tracking doesn't lock the view and makes desktop 
replicants happy while clicking and dragging around. Fixes #880, #7241 
and certainly other tickets, that i will revisit, about refresh locks 
on the desktop or mouse related bugs. Based on a reusable MessageFilter and the 
recent B_MOUSE_IDLE message. Some parts are ported from the old code
and could use further simplification.

There should be no intentional user fonctional change, except: 
- slightly bigger threshold radius, shorter duration thresholds
 (= 1.0 x the system-wide doubleclick setting)
- not reimplemented: quickening threshold when holding shift while dragging
 a pose over a destination pose.

Some parts are ported from the old code and could use further simplification.
There is one known minor regression with autoscrolling while 
rect-selecting but that will be better fixed with some changes to the 
autoscroll code. Will address that ASAP. As for the unknown regressions, 
please test :)


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@41892 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/shared/LongAndDragTrackingFilter.h

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2009, Alexandre Deckner, [email protected]
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef LONG_AND_DRAG_TRACKING_FILTER_H
+#define LONG_AND_DRAG_TRACKING_FILTER_H
+
+
+#include <MessageFilter.h>
+#include <Point.h>
+
+
+class BHandler;
+class BMessageRunner;
+
+
+namespace BPrivate {
+
+class LongAndDragTrackingFilter : public BMessageFilter {
+public:
+								LongAndDragTrackingFilter(
+									uint32 longMessageWhat,
+									uint32 dragMessageWhat,
+									float radiusThreshold = 4.0f,
+									bigtime_t durationThreshold = 0);
+								~LongAndDragTrackingFilter();
+
+			filter_result		Filter(BMessage* message, BHandler** target);
+
+private:
+			void				_StopTracking();
+
+			uint32				fLongMessageWhat;
+			uint32				fDragMessageWhat;
+			BMessageRunner*		fMessageRunner;
+			BPoint				fClickPoint;
+			uint32				fClickButtons;
+			float				fSquaredRadiusThreshold;
+			bigtime_t			fDurationThreshold;
+};
+
+}	// namespace BPrivate
+
+using BPrivate::LongAndDragTrackingFilter;
+
+#endif	// LONG_AND_DRAG_TRACKING_FILTER_H
+