ex11 - brain dump 3

Vlad Dumitrescu <>
Mon Jan 19 12:22:34 CET 2004


From: "Joachim Durchholz" <>
> Vlad Dumitrescu wrote:
> > Input events are easy to abstract out, because
> > they're just messages;
>
> Not sure what exactly you mean, but there's more than meets the eye with
> input events.
> You need at least two levels of events:
> 1) Basic IO: key press, key release, mouse button press/release, mouse move.
> 2) "Predigested" events: mouse click, double click, drag (and subsequent
> drop), keypress, keeping a key pressed, change in shift-lock state, etc.
> etc.
> 3) High-level events: when a window area is uncovered and must be
> redrawn, when the user selects a different color scheme, to be applied
> to all applications, when the user logs out, when the computer is about
> to be shut down, when the contents of a text field changes, etc. etc. etc.

Yes, I am aware of all those events. What I was thinking about is that in an
Erlang implementation, these events will most probably "move around" as
messages, and then it's realtively easy to convert them to an
environmnet-neutral set. In comparison, drawing something is much more dependent
on the target. One could also choose a neutral model for drawing (possibly
PS/PDF like), but it's not an easy task. For example, it won't work with PicoGUI
:-)

/Vlad





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