Re: [Plib-users] Lost and buffered key events

[Joerg H. <jo...@lu...>]

Hi all,

I solved at least one problem, and thought it might be useful for others 
to have the solution:

[...]
> 2) I noticed as well that some of my menus are very slow to react.
>    After some searching I again printed the events inside the event
>    loop of pwX11.
>    While my application updates the frames roughly every 0.03 seconds,
>    sometimes events get not delivered at once, but are delayed, and
>    after some time suddenly all events get delivered in the same call to
>    the event handler, e.g. I press and release 'down', 'down',
>    'up'. I get the event:
>     press 'down'
>    The nothing for 'some time', while I release
>    the key, press 'down' again, release 'down', press 'up'.
>    Then suddenly there are three events reported in the event loop.

It turns out that the main reason was a big background texture 
(512x512). When the texture was disabled, everything was fine. But even 
a small texture (16x16) scaled up on the 800x600 screen would show the 
slow down.

So I guess that the X server appeared to be overloaded, since the 
texture was drawn too quickly/often - and as a result of this (again: I 
guess) keyboard events were buffered.

As a first solution, I then used some kind of 'lazy update' - only 
drawing the background picture if anything was changed on the screen. 
This worked fine, but is quite a bit of implementation work. The much 
easier solution: I added a small delay (usleep(2000)) before drawing the 
background texture, and everything is fine now - this delay is not 
noticeable for the user.

On a side note: this solution improved another user's problem of having 
a delay when going from one screen to the next as well.

Best regards,
     Joerg

-- 
----------------------------------------------------------------
Joerg Henrichs
Luding Administration
e-mail: jo...@lu...
URL:    http://luding.org