Event redirection adventures
ufz6 at rz.uni-karlsruhe.de
Mon Jan 9 06:51:10 PST 2006
1- some composite manager may want more or full control of event proccessing
2- some composite manager doesn't need controlling event proccing. Here
there is no need for event redirection
For 1- event redirection requered before (hit detection) occure, so that the
controll application (the composite manager client) could decide the start
point of hit detection. Example: consider such window tree in Xserver, w & X
w w w w
Upon internal calculation of contol application it decide to start search
from "X" window. Requerement for this that the controll application receive
events before they should be send out to clients. Making this redirection in
"hit detection" rather than raw events may douplicate event proccesing .
> There are two basic computations needed in this environment.
> The first is to transform an arbitrary screen position to a
> position relative to a specific window (coord
> transformation). The second is to detect which window is
> directly under a specific screen position (hit detection).
It is not effiecent to let the controll application to answer, for that it
need the complete window hierarchie and coordination for each window and
that very expensive. It is easyer for controll application to detect which
top level window is under specific screen position acording to it's internal
structure and translate this to relative to that top level window, Xserver
can answer which child window is under this relative coord transformation.
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