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List:       kde-multimedia
Subject:    PlayObject changes
From:       Stefan Westerfeld <stefan () space ! twc ! de>
Date:       2000-07-17 22:54:03
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   Hi!

I've made a few changes to PlayObject today. Like always, changing interfaces
is binary incompatible. So please if there are any remaining issues, or you'd
like to have it different, bring them up soon, as we won't be able to change
these issues later (especially not after the KDE2.0 release).

1. Changed posFinished to posIdle:

 enum poState {
+  posIdle,
   posPlaying,
-  posFinished,
   posPaused
 };                                                                             

A PlayObject is supposed to start up IDLE now (not PAUSED). Then, if the user
pushes play, the PlayObject is supposed to get PLAYING, until it has played
everything (i.e. Song done), then it is going IDLE again.

You can force a PlayObject to go IDLE anytime using a new method called halt(),
this should also seek back to the beginning, see below. If you use pause(),
the PlayObject will be PAUSED, and if you do play() again, it will be PLAYING
again. Well, I hope this is a logic choice of states now.

2. The halt() method:

+   /**
+     * stop playing the media. Normally this function would called stop,
+     * but the name is reserved for the start/stop mechanism of the
+     * aRts objects.
+     */
+    void halt();
 };                                                                             

Usually, this method would be called stop(), but well, aRts already uses
start() and stop() for other things (streaming object starting/stopping),
so this was the second best choice.

Note: there was no stop before, because we said: well, you can always stop
it by using playObject = Arts::PlayObject::null(), which will cause its
reference count to drop and the PlayObject to go away. But for the user
interface it seems more convenient/logic to call halt() whenever the user
pushes the stop button, than terminating the PlayObject.

3. Making more attibutes readonly:

-    attribute string description;
-    attribute poTime currentTime;
+    readonly attribute string description;
+    readonly attribute poTime currentTime;                                     

While it would make sense to set currentTime (i.e. seek), we have an explicit
seek already, which is maybe more understandable. We needed to get rid of one
and I choose setting currentTime as less intuitive.

On the other hand, the PlayObject should know it's description (i.e. ID3
Tag), and setting this is not what you'll usually be able to do. Hmm, this
might be discussable, but I removed it for now, unless there are any strong
objections.

 * * *

If you would like to have anything done different, now is the chance to say
it ;)

Also, please Martin and Charles, look into your sources and see that I didn't
break anything essential... especially halt() is probably unused/unimplemented,
and the mpeglib PlayObjects may come up paused (instead of idle). The wave
PlayObject in kdelibs should be okay.

   Cu... Stefan
-- 
  -* Stefan Westerfeld, stefan@space.twc.de (PGP!), Hamburg/Germany
     KDE Developer, project infos at http://space.twc.de/~stefan/kde *-         
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