[maemo-developers] detect window iconified/maximized in SDL

[From: eero.tamminen at nokia.com]

Hi,
________________________________________
From: maemo-developers-bounces at maemo.org [maemo-developers-bounces at maemo.org] On Behalf Of Hamalainen Kimmo (Nokia-D/Helsinki)

On Wed, 2009-03-25 at 09:14 +0100, Hamalainen Kimmo (Nokia-D/Helsinki)
> > I would like to detect when an SDL application gets iconified. Than I
> > can pause it to save power. In theory the SDL_ACTIVEEVENT should be
> > generated and event.active should give me the info I need however I do
> > not get these type of events.

Note that it's not enough just to use SDL function to wait for events when it's
invisible / idle. SDL does 10Hz polling even when waiting for events which will 
drain battery pretty soon.  (I filed a bug about that for upstream SDL several
years ago, it's still not fixed, but there's a broken patch available.)

Because of this, in my own SDL code I use select() when the process should
be idle in RAM longer times without draining battery. You can get the SDL X
socket file descriptor like this:
--------------
/**
 * Return the X connection socket or zero
 */
static int GetUISocket(void)
{
	SDL_SysWMinfo info;
	SDL_VERSION(&info.version);
	if (!SDL_GetWMInfo(&info)) {
		return 0;
	}
	return ConnectionNumber(info.info.x11.display);
}
------------

Your program could use something like that also with an an explicit (user invoked)
pause functionality.


  - Eero