[UFO-devel] Events and layered panes

[Andreas B. <b_...@gm...>]

Hi
attached is a patch that I have sent before, I believe (or at least 
mentioned). It implements layered pane compatible event handling.
Umm, well, this patch has been used in Boson for quite some time, here the 
comment in my README about this patch:

- Patch to uabstractcontext.hpp, uabstractcontext.cpp and uwidget.cpp
  to improve events for our needs:
  Instead of delivering a mouse event to root->getVisibleWidgetAt(), we
  implement a getVisibleWidgetsDFS() function, that starts at the root and 
finds
  all currently visible widgets (at the relevant point) using a depth first 
search
  and returns them in a stack.
  We then dispatch it to every widget on the stack until one widget consumes
  the event (in that case we stop then).
  This especially fixes layered panes: previously an event was delivered to 
the
  topmost layer only and to the layered pane itself, if the widget was not
  interested in that event. Now the event is first delivered to the topmost
  layer, then to the layers below it, then to the layered pane.


This patch makes pretty much the difference between "libufo is usable" and 
"libufo is unusable" for us: it is extremely important that a click on a 
button is dispatched to the button and clicks on everything else is delivered 
to the stuff below that. (yeah, that was the simple version)

I have been maintaining this patch for 2 or 3 libufo updates already and it 
starts to go on my nerves. I know that my (non-trivial) patches are not very 
liked here, so is there any chance this every makes it to official cvs? If 
not I'll investigate whether it is possible to subclass ufo::UAbstractContext 
instead and achieve the same in our extension library, so that I don't have 
to re-apply the patches every time (well - at least not all of them. The 
ufo::UWidget::dispatchEvent() part cannot be done outside of libufo).

CU
Andi