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+Split gestures into recognition and application
+-----------------------------------------------
+
+Gesture detection is not an exact science, but the algorithms
+inevitably involve decisions influenced by what gestures are available
+to choose from. Therefore, the recognition should be considered an
+inherent property of the device itself, regardless of user interaction
+context. Just imagine having a keyboard that resized slightly
+everytime you switched from chrome to gimp.
+
+
+Tag events as being part of a gesture
+-------------------------------------
+
+One of the problems faced when replacing one set of events with
+another is where and how this filtering should take place. One window
+might listen for spiral gestures, whereas another window is a paint
+program where you actually want to draw a spiral. By introducing a
+relation between a gesture and an event, filtering becomes something
+simple that can be performed close to the window. The relation can be
+implemented as a bitmask representing what gestures the event is part
+of.
+
+
+Help the client to keep track of active gestures
+------------------------------------------------
+
+A gesture starts, continues, and either completes or aborts.
+A client that listens to a subset of gestures will have to keep track.
+Compatible to Qt approach.
+
+
+Allow clients to listen to different gestures
+---------------------------------------------
+
+Clients listening on certain gestures will get those gesture events that
+apply to the client, which makes it possible for different clients to
+listen to different types of gestures. For instance, having an MT drawing
+program next to a web browser, a two finger stroke in the drawing program
+will result in two lines, whereas in the web browser, it will scroll the
+text.
+
+
+Propagate gesture events based on the focus point
+-------------------------------------------------
+
+Like pointer events, a gesture applies to a window or a window manager,
+based on where it is performed on the screen. In order to route the gesture
+events to the right window, we propagate them through the window hierarchy
+based on the gesture focus points. Based on the target windows, their
+respective gesture type masks, and the active set of gestures, final
+gesture events are emitted to the right windows.
+
+
+Allow Window Manager to grab system-wide gestures
+-------------------------------------------------
+
+Even if clients are not listening to global window-manager gestures, it
+could well be that no other gestures should be displayed while the global
+gesture is taking place.